@ARTICLE{Aborisade2010, author = {D. O. Aborisade and Olanrewaju Jelili Oyelade}, title = {{HierarchyMap}: A Novel Approach to {Treemap} Visualization of Hierarchical Data}, journal = {Global Journal of Computer Science and Technology}, year = {2010}, volume = {9}, pages = {77--81}, number = {5 v.2}, abstract = {The HierarchyMap describes a novel approach for Treemap Visualization method for representing large volume of hierarchical information on a 2-dimensional space. HierarchyMap algorithm is a new ordered treemap algorithm. Results of the implementation of HierarchyMap treemap algorithm show that it is capable of representing several thousands of hierarchical data on 2-dimensional space on a computer and Portable Device Application (PDA) screens while still maintaining the qualities found in existing treemap algorithms such as readability, low aspect ratio, reduced run time, and reduced number of thin rectangles. The HierarchyMap treemap algorithm is implemented in Java programming language and tested with dataset of Departmental and Faculty systems of Universities, Family trees, Plant and Animal taxonomy structures.}, url = {http://computerresearch.org/index.php/computer/article/view/868} } @INPROCEEDINGS{Adamoli2010, author = {Andrea Adamoli and Matthias Hauswirth}, title = {Trevis: A context tree visualization and analysis framework and its use for classifying performance failure reports}, pages = {73--82}, abstract = {When developers profile their applications to identify performance problems, they normally use profilers producing calling context trees. A calling context tree (CCT) represents the caller-callee relationships of a program. A dynamically collected CCT provides method coverage information. The CCTs produced by profilers also include method hotness information. Trevis, our context tree visualization and analysis framework, allows users to visualize, compare, cluster, and intersect CCTs produced by profilers. We evaluate Trevis in the context of a novel profiling tool called FlyBy. FlyBy runs transparently on an end-user's computer and continuously samples the applications' call stack. When the user perceives the application as sluggish, she presses a "Was Slow!" button to tell FlyBy to file a performance failure report. The report contains the CCT based on the call stack samples FlyBy gathered over the last few seconds before the user pressed the button. We show how Trevis allows us to visualize and classify FlyBy bug reports.}, doi = {10.1145/1879211.1879224}, year = {2010}, booktitle = {SoftVis'10: Proceedings of the Symposium on Software Visualization}, editor = {Alexandru Telea and Carsten G\"org and Steven P. Reiss}, publisher = {ACM Press}, isbn = {9781450300285} } @INPROCEEDINGS{Ahmed2007, author = {Adel Ahmed and Seok-Hee Hong}, title = {Navigation techniques for {2.5D} graph layout}, pages = {81--84}, abstract = {In this paper, we consider the problem of navigating graphs drawn in 2.5 dimensions. First, we define criteria for good navigation and then present various methods to satisfy some of the criteria. In particular, we design and implement methods for trees, clustered graphs and hierarchical graphs drawn in 2.5 dimensions.}, doi = {10.1109/APVIS.2007.329279}, year = {2007}, booktitle = {APVIS'07: Proceedings of the Asia Pacific Symposium on Information Visualization}, editor = {Seok-Hee Hong and Kwan-Liu Ma}, publisher = {IEEE Computer Society}, series = {Conference in Research and Practice in Information Technology}, isbn = {1424408083} } @ARTICLE{Ahuja1986, author = {Narendra Ahuja}, title = {Efficient planar embedding of trees for {VLSI} layouts}, journal = {Computer Vision, Graphics, and Image Processing}, year = {1986}, volume = {34}, pages = {189--203}, number = {2}, abstract = {The use of planar polygonal partitioning schemes for planar embedding of tree structures is examined. Two layout designs based on recursive square and triangular decompositions are described for trees having branching factors of k*k and k*k-1, where k is an integer. The former design allocates the same amount of area to nodes at all levels and requires a total area linear in the number N of nodes in the tree. The latter design assigns increasing area to nodes closer to the root and requires a total area of O[N(k*k/(k*k-1))logN]. The longest interconnection has a length of O(sqrt(Area(N))) in each case.}, doi = {10.1016/S0734-189X(86)80058-5} } @ARTICLE{Allen2002, author = {Maryellen Mott Allen}, title = {The hype over {Hyperbolic Browsers}}, journal = {Online}, year = {2002}, volume = {26}, pages = {20--28}, number = {3}, abstract = {Considers complaints about the usability in the human-computer interaction aspect of information retrieval and discusses information visualization, the Online Library of Information Visualization Environments, hyperbolic information structure, subject searching, real-world applications, relational databases and hyperbolic trees, and the future of visual information structures.}, url = {http://www.infotoday.com/online/may02/allen.htm} } @INPROCEEDINGS{Andrews1997, author = {Keith Andrews and Josef Wolte and Michael Pichler}, title = {Information Pyramids\texttrademark: A New Approach to Visualising Large Hierarchies}, pages = {49--52}, note = {Late Breaking Hot Topic Paper}, abstract = {This paper presents work in progress on a new technique for visualising and manipulating large hierarchies. The Information Pyramids approach compactly visualises hierarchical structures in three dimensions using pyramid-like structures, which grow upwards as the hierarchy is descended. The technique is described in the context of our early experience with a prototype file system visualiser based on Information Pyramids.}, } year = {1997}, booktitle = {Visualization'97: Proceedings of the IEEE Conference on Visualization}, editor = {Roni Yagel and Hans Hagen}, publisher = {ACM Press}, isbn = {1581130112} } @INPROCEEDINGS{Andrews1998, author = {Keith Andrews and Helmut Heidegger}, title = {Information Slices: Visualising and Exploring Large Hierarchies using Cascading, Semi-Circular Discs}, pages = {9--12}, note = {Late Breaking Hot Topic Paper}, abstract = {This paper presents work in progress on a new technique for visualising and manipulating large hierarchies. The information slices approach compactly visualises hierarchical structures using a series of semi-circular discs. The technique is described in the context of our early experience with a prototype file system visualiser based on information slices.}, } year = {1998}, booktitle = {InfoVis'98: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Graham Wills and John Dill}, publisher = {IEEE Computer Society}, isbn = {0818690933} } @ARTICLE{Andrews2002, author = {Keith Andrews and Wolfgang Kienreich and Vedran Sabol and Jutta Becker and Georg Droschl and Frank Kappe and Michael Granitzer and Peter Auer and Klaus Tochtermann}, title = {The {InfoSky} visual explorer: Exploiting hierarchical structure and document similarities}, journal = {Information Visualization}, year = {2002}, volume = {1}, pages = {166--181}, number = {3/4}, abstract = {InfoSky is a system enabling users to explore large, hierarchically structured document collections. Similar to a real-world telescope, InfoSky employs a planar graphical representation with variable magnification. Documents of similar content are placed close to each other and are visualised as stars, forming clusters with distinct shapes. For greater performance, the hierarchical structure is exploited and force-directed placement is applied recursively at each level on much fewer objects, rather than on the whole corpus. Collections of documents at a particular level in the hierarchy are visualised with bounding polygons using a modified weighted Voronoi diagram. Their area is related to the number of documents contained. Textual labels are displayed dynamically during navigation, adjusting to the visualisation content. Navigation is animated and provides a seamless zooming transition between summary and detail view. Users can map metadata such as document size or age to attributes of the visualisation such as colour and luminance. Queries can be made and matching documents or collections are highlighted. Formative usability testing is ongoing; a small baseline experiment comparing the telescope browser to a tree browser is discussed.}, doi = {10.1057/palgrave.ivs.9500023} } @INPROCEEDINGS{Andrews2002a, author = {Keith Andrews}, title = {Visual Exploration of Large Hierarchies with Information Pyramids}, pages = {793--798}, abstract = {Information pyramids compactly visualise large hierarchical structures in three dimensions using pyramid-like structures, which grow upwards as the hierarchy deepens. A plateau represents the root of the tree; other, smaller plateaus arranged on top of it represent its subtrees. Separate glyphs are used to represent leaf nodes such as files or documents and navigational facilities are provided for interactive exploration. Two generations of information pyramids prototype are described and discussed.}, doi = {10.1109/IV.2002.1028871}, year = {2002}, booktitle = {IV'02: Proceedings of the International Conference on Information Visualisation}, publisher = {IEEE Computer Society}, isbn = {0769516564} } @INPROCEEDINGS{Andrews2003, author = {Keith Andrews and Wolfgang Kienreich and Vedran Sabol and Michael Granitzer}, title = {Visualising Large Hierarchically Structured Document Repositories with {InfoSky}}, pages = {70--71}, abstract = {InfoSky is an interactive system for the exploration of large, hierarchically structured document collections. InfoSky employs a planar graphical representation with variable magnification like a real-world telescope. The hierarchical structure is reflected using recursive subdivision into Voronoi polygons. At each level of the hierarchy documents and subcollections are positioned according to the similarity of their content using a force-directed placement technique. Documents are assumed to have significant textual content, which can be extracted with specialised tools. The hierarchical structure is exploited for greater performance. Force-directed placement is applied recursively at each level on the objects at that level rather than on the whole corpus.}, url = {http://conferences.computer.org/infovis/files/compendium2003.pdf}, year = {2003}, booktitle = {InfoVis'03: Poster Compendium of the IEEE Symposium on Information Visualization}, } @INPROCEEDINGS{Andrews2004, author = {Keith Andrews and Wolfgang Kienreich and Vedran Sabol and Michael Granitzer}, title = {The visualisation of large hierarchical document spaces with {InfoSky}}, abstract = {It is no longer unusual for large document collections to contain many millions of documents. In order to manage this size of repository, it is often essential to structure the repository according to a thematic classification hierarchy. InfoSky is a system enabling users to explore such large, hierarchically structured document collections. Similar to a real-world telescope, InfoSky employs a planar graphical representation with variable magnification. The hierarchical structure is represented by recursive Voronoi subdivision of the available space. At each level, larger subcollections are assigned more space and related subcollections gravitate towards one another. Individual documents at each level of the hierarchy are represented by stars placed according to their similarity. Finally, InfoSky extracts and displays descriptors describing the essential theme of each subcollection at each level of the hierarchy.}, url = {http://dcgi.felk.cvut.cz/cgg/infoviz04/papers/andrews.pdf}, year = {2004}, booktitle = {CODATA'04: Proceedings of the Workshop on Information Visualisation, Presentation and Design} } @INPROCEEDINGS{Appert2006, author = {Caroline Appert and Jean-Daniel Fekete}, title = {{ControlTree}: Navigating and Selecting in a Large Tree}, pages = {47--48}, abstract = {We introduce ControlTree, a novel interface using crossing interaction to navigate and select nodes in a large tree. ControlTree combines an optimized dynamic layout with interaction features to quickly reach a node in a node-link tree representation.}, url = {http://www.acm.org/uist/archive/adjunct/2006/pdf/demos/p47-appert.pdf}, year = {2006}, booktitle = {UIST'06: Adjunct Proceedings of the Annual ACM Symposium on User Interface Software and Technology}, publisher = {ACM Press}, isbn = {1595933131} } @INPROCEEDINGS{Appert2007, author = {Caroline Appert and Jean-Daniel Fekete}, title = {Naviguer dans des grands arbres avec {ControlTree}}, pages = {139--142}, abstract = {This article presents ControlTree, a relevant technique to select a node is a very large node-link representation using a continuous interaction. The node-link representation is dynamic and driven by the cursor location to optimize screen space and to ease the selections. ControlTree uses a snapping mechanism and adapts the OrthoZoom technique to offer an alternative to common "point-and-click" techniques. We also present a preliminary theoretical evaluation showing that ControlTree is a promising technique.}, doi = {10.1145/1541436.1541463}, year = {2007}, booktitle = {IHM'07: Proceedings of the International Conference on Association Francophone d'Interaction Homme-Machine}, editor = {Carlos Agon and Olivier Delerue}, publisher = {ACM Press}, isbn = {9781595937919} } @PATENT{Armitage2014, author = {John Armitage}, title = {Method and system for generating a {Columnar Tree Map}}, number = {US 8854371 B2}, year = {2014}, abstract = {A method and system to generate a columnar tree map of a hierarchical structure is provided. An example system comprises a memory, at least one processor coupled to the memory, a data access module configured to access a hierarchical data structure, and a tree map generator to generate a tree map using at least one processor. The tree map generator generates and renders a tree map for a target data set based on the size and dimensions of a viewing area provided on a target display device, the values associated with categories in the data set, and a predetermined column width.}, url = {http://www.freepatentsonline.com/8854371.html} } @PATENT{Armitage2016, author = {John Armitage}, title = {Navigable visualization of a hierarchical data structure}, number = {US 9229609 B2}, year = {2016}, abstract = {An example system generates, for a target data set, a navigable space based upon quantitatively-visualized menus. The navigable space is provided within a viewing area on a display device and comprises a stacked bar chart at the left end of a viewing area and, on the right end of the viewing area, a bar graph comprising set of bars. The stacked bar chart is also usable as an actionable menu.}, url = {http://www.freepatentsonline.com/9229609.html} } @ARTICLE{Auber2013, author = {David Auber and Charles Huet and Antoine Lambert and Benjamin Renoust and Arnaud Sallaberry and Agnes Saulnier}, title = {{GosperMap}: Using a {Gosper} curve for laying out hierarchical data}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2013}, volume = {19}, pages = {1820--1832}, number = {11}, abstract = {The emergence of very large hierarchies that result from the increase in available data raises many problems of visualization and navigation. On data sets of such scale, classical graph drawing methods do not take advantage of certain human cognitive skills such as shape recognition. These cognitive skills could make it easier to remember the global structure of the data. In this paper, we propose a method that is based on the use of nested irregular shapes. We name it GosperMap as we rely on the use of a Gosper Curve to generate these shapes. By employing human perception mechanisms that were developed by handling, for example, cartographic maps, this technique facilitates the visualization and navigation of a hierarchy. An algorithm has been designed to preserve region containment according to the hierarchy and to set the leaves' sizes proportionally to a property, in such a way that the size of nonleaf regions corresponds to the sum of their children's sizes. Moreover, the input ordering of the hierarchy's nodes is preserved, i.e., the areas that represent two consecutive children of a node in the hierarchy are adjacent to one another. This property is especially useful because it guarantees some stability in our algorithm. We illustrate our technique by providing visualization examples of the repartition of tax money in the US over time. Furthermore, we validate the use of the GosperMap in a professional documentation context and show the stability and ease of memorization for this type of map.}, doi = {10.1109/TVCG.2013.91} } @ARTICLE{Aydin2010, author = {Burcu Aydin and Gabor Pataki and Haonan Wang and Alim Ladha and Elizabeth Bullitt and J.S. Marron}, title = {Visualizing the structure of large trees}, journal = {arXiv.org e-print service}, year = {2010}, volume = {arXiv:1001.0951v2}, abstract = {This study introduces a new method of visualizing complex tree structured objects. The usefulness of this method is illustrated in the context of detecting unexpected features in a data set of very large trees. The major contribution is a novel two-dimensional graphical representation of each tree, with a covariate coded by color. The motivating data set contains three dimensional representations of brain artery systems of 105 subjects. Due to inaccuracies inherent in the medical imaging techniques, issues with the reconstruction algo- rithms and inconsistencies introduced by manual adjustment, various discrepancies are present in the data. The proposed representation enables quick visual detection of the most common discrepancies. For our driving example, this tool led to the modification of 10\% of the artery trees and deletion of 6.7\%. The benefits of our cleaning method are demonstrated through a statistical hypothesis test on the effects of aging on vessel structure. The data cleaning resulted in improved significance levels.}, url = {http://arxiv.org/abs/1001.0951v2} } @ARTICLE{Aydin2011, author = {Burcu Aydin and Gabor Pataki and Haonan Wang and Alim Ladha and Elizabeth Bullitt and J.S. Marron}, title = {Visualizing the Structure of Large Trees}, journal = {Electronic Journal of Statistics}, year = {2011}, volume = {5}, pages = {405--420}, abstract = {This study introduces a new method of visualizing complex tree structured objects. The usefulness of this method is illustrated in the context of detecting unexpected features in a data set of very large trees. The major contribution is a novel two-dimensional graphical representation of each tree, with a covariate coded by color. The motivating data set contains three dimensional representations of brain artery systems of 105 subjects. Due to inaccuracies inherent in the medical imaging techniques, issues with the reconstruction algo- rithms and inconsistencies introduced by manual adjustment, various discrepancies are present in the data. The proposed representation enables quick visual detection of the most common discrepancies. For our driving example, this tool led to the modification of 10\% of the artery trees and deletion of 6.7\%. The benefits of our cleaning method are demonstrated through a statistical hypothesis test on the effects of aging on vessel structure. The data cleaning resulted in improved significance levels.}, url = {http://projecteuclid.org/euclid.ejs/1305034908} } @INPROCEEDINGS{Bachmaier2005, author = {Christian Bachmaier and Ulrik Brandes and Barbara Schlieper}, title = {Drawing Phylogenetic Trees}, pages = {1110--1121}, abstract = {We present linear-time algorithms for drawing phylogenetic trees in radial and circular representations. In radial drawings given edge lengths (representing evolutionary distances) are preserved, but labels (names of taxons represented in the leaves) need to be adjusted, whereas in circular drawings labels are perfectly spread out, but edge lengths adjusted. Our algorithms produce drawings that are unique solutions to reasonable criteria and assign to each subtree a wedge of its own. The linear running time is particularly interesting in the circular case, because our approach is a special case of Tutte's barycentric layout algorithm involving the solution of a system of linear equations.}, doi = {10.1007/11602613_110}, year = {2005}, booktitle = {ISAAC'05: Proceedings of the International Symposium on Algorithms and Computations}, editor = {Xiaotie Deng and Dingzhu Du}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540309352}, } @INPROCEEDINGS{Bachmaier2008, author = {Christian Bachmaier and Franz J. Brandenburg and Wolfgang Brunner and Andreas Hofmeier and Marco Matzeder and Thomas Unfried}, title = {Tree Drawings on the Hexagonal Grid}, pages = {372--383}, abstract = {We consider straight-line drawings of trees on a hexagonal grid. The hexagonal grid is an extension of the common grid with inner nodes of degree six. We restrict the number of directions used for the edges from each node to its children from one to five, and to five patterns: straight, Y, psi, X, and full. The psi-drawings generalize hv- or strictly upward drawings to ternary trees. We show that complete ternary trees have a psi-drawing on a square of size and general ternary trees can be drawn within area. Both bounds are optimal. Sub-quadratic bounds are also obtained for X-pattern drawings of complete tetra trees, and for full-pattern drawings of complete penta trees, which are 4-ary and 5-ary trees. These results parallel and complement the ones of Frati for straight-line orthogonal drawings of ternary trees. Moreover, we provide an algorithm for compacted straight-line drawings of penta trees on the hexagonal grid, such that the direction of the edges from a node to its children is given by our patterns and these edges have the same length. However, drawing trees on a hexagonal grid within a prescribed area or with unit length edges is NP-hard.}, doi = {10.1007/978-3-642-00219-9_36}, year = {2008}, booktitle = {GD'08: Proceedings of the International Symposium on Graph Drawing}, editor = {Ioannis G. Tollis and Maurizio Patrignani}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642002182}, } @ARTICLE{Bagheri2005, author = {Alireza Bagheri and Mohammadreza Razzazi}, title = {How to draw free trees inside bounded simple polygons}, journal = {Journal of Universal Computer Science}, year = {2005}, volume = {11}, pages = {804--829}, number = {6}, abstract = {In this paper we investigate polyline grid drawing of free trees on 2D grids which are bounded by simple polygons. We focus on achieving uniform node distribution while we also try to achieve minimum edge crossings. We do not consider achieving symmetry as a mandatory task, but our algorithm can exploit some symmetries present in both the given trees and the given polygons. To our knowledge, our work is the first attempt for developing algorithms that draw graphs on regions which are bounded by simple polygons.}, doi = {10.3217/jucs-011-06-0804} } @ARTICLE{Baker1995, author = {Marla J. Baker and Stephen G. Eick}, title = {Space-filling Software Visualization}, journal = {Journal of Visual Languages and Computing}, year = {1995}, volume = {6}, pages = {119--133}, number = {2}, abstract = {SeeSys is a system embodying a technique for visualizing statistics associated with code that is divided hierarchically into subsystems, directories and files. This technique can display the relative sizes of the components in the system, the relative stability of the components, the location of new functionality and the location of error-prone code with many bug fixes. Using animation, it can display the historical evolution of the code. Applying this technique, the source code from a multi-million line production software product is visualized.}, doi = {10.1006/jvlc.1995.1007} } @INPROCEEDINGS{Balzer2004, author = {Michael Balzer and Oliver Deussen}, title = {Hierarchy based {3D} Visualization of Large Software Structures}, pages = {81--82}, abstract = {Modern object-oriented programs are hierarchical systems with many thousands of interrelated subsystems. Visualization helps developers to better comprehend these large and complex systems. This work presents a three-dimensional visualization technique that represents the static structure of object-oriented software using distributions of three-dimensional objects on a two-dimensional plane. The visual complexity is reduced by adjusting the transparency of object surfaces to the distance of the viewpoint. An approach called Hierarchical Net is proposed for a clear representation of the relationships between the subsystems.}, doi = {10.1109/VISUAL.2004.39}, year = {2004}, booktitle = {Visualization'04: Poster Compendium of the IEEE Visualization Conference}, url = {http://conferences.computer.org/infovis/files/compendium2004.pdf} } @INPROCEEDINGS{Balzer2005, author = {Michael Balzer and Oliver Deussen}, title = {Voronoi Treemaps}, pages = {49--56}, abstract = {Treemaps are a well known method for the visualization of attributed hierarchical data. Previously proposed treemap layout algorithms are limited to rectangular shapes, which cause problems with the aspect ratio of the rectangles as well as with identifying the visualized hierarchical structure. The approach of Voronoi treemaps presented in this paper eliminates these problems through enabling subdivisions of and in polygons. Additionally, this allows for creating treemap visualizations within areas of arbitrary shape, such as triangles and circles, thereby enabling a more flexible adaptation of treemaps for a wider range of applications.}, doi = {10.1109/INFVIS.2005.1532128}, year = {2005}, booktitle = {InfoVis'05: Proceedings of the IEEE Symposium on Information Visualization}, editor = {John Stasko and Matthew O. Ward}, publisher = {IEEE Computer Society}, isbn = {078039464X} } @INPROCEEDINGS{Band2006, author = {Zvi Band and Ryen W. White}, title = {{PygmyBrowse}: A small screen tree browser}, pages = {514--519}, abstract = {We present PygmyBrowse, a browser that allows users to navigate a tree data structure in a limited amount of display space. A pilot evaluation of PygmyBrowse was conducted, and results suggest that it reduces task completion times and increases user satisfaction over two alternative node-link tree browsers.}, doi = {10.1145/1125451.1125562}, year = {2006}, booktitle = {CHI'06: Extended abstracts of the SIGCHI conference on Human Factors in Computing Systems}, publisher = {ACM Press}, isbn = {1595932984} } @ARTICLE{Baron1969, author = {Margaret E. Baron}, title = {A Note on the Historical Development of Logic Diagrams: {L}eibniz, {E}uler and {V}enn}, journal = {The Mathematical Gazette}, year = {1969}, volume = {53}, pages = {113--125}, number = {384}, doi = {10.2307/3614533} } @INPROCEEDINGS{Baudel2011, author = {Thomas Baudel and Bertjan Broeksema}, title = {A generic algorithm for sequential, rectangular, space filling layouts}, abstract = {We present a generic algorithm to sequentially pave a rectangular area with smaller, fixed-surface, rectangles. The parameters of this algorithm are functional, and it covers the full design space considered. This class of layouts is interesting, because it includes all kinds of treemaps involving the placement of rectangles. For instance, Slice and dice, Squarified, Strip and Pivot layouts are obtained through various formulations of two simple chunking and phrasing functions. Some new and potentially interesting layouts which can be generated using our algorithm are introduced, such as spiral treemaps and data dependent variations of known layout strategies.}, url = {http://www.cs.rug.nl/~alext/PAPERS/InfoVis11/posterBroeksema.pdf}, year = {2011}, booktitle = {InfoVis'11: Poster at the IEEE Conference on Information Visualization} } @ARTICLE{Baudel2012, author = {Thomas Baudel and Bertjan Broeksema}, title = {Capturing the Design Space of Sequential Space-Filling Layouts}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2012}, volume = {18}, pages = {2593--2602}, number = {12}, abstract = {We characterize the design space of the algorithms that sequentially tile a rectangular area with smaller, fixed-surface, rectangles. This space consist of five independent dimensions: Order, Size, Score, Recurse and Phrase. Each of these dimensions describe a particular aspect of such layout tasks. This class of layouts is interesting, because, beyond encompassing simple grids, tables and trees, it also includes all kinds of treemaps involving the placement of rectangles. For instance, Slice and dice, Squarified, Strip and Pivot layouts are various points in this five dimensional space. Many classic statistics visualizations, such as 100\% stacked bar charts, mosaic plots and dimensional stacking, are also instances of this class. A few new and potentially interesting points in this space are introduced, such as spiral treemaps and variations on the strip layout. The core algorithm is implemented as a JavaScript prototype that can be used as a layout component in a variety of InfoViz toolkits.}, doi = {10.1109/TVCG.2012.205} } @INPROCEEDINGS{Beaudoin1996, author = {Luc Beaudoin and Marc-Antoine Parent and Louis C. Vroomen}, title = {Cheops: A Compact Explorer For Complex Hierarchies}, pages = {87--92}, abstract = {As the amount of electronic information explodes, hierarchies to handle this information become huge and complex. Visualizing and interacting with these hierarchies become daunting tasks. The problem is exacerbated if the visualization is to be done on massmarket personal computers, with limited processing power and visual resolution. Many of the current visualization techniques work effectively for hierarchies of 1000 nodes. But as the number of nodes increases toward 5000 nodes, these techniques tend to break down. Hierarchies above 5000 nodes usually require special modifications such as clustering, which can affect visual stability. This paper introduces Cheops, a novel approach to the representation, browsing and exploration of huge, complex information hierarchies such as the Dewey Decimal system, which can contain between 1 million and 1 billion nodes. The Cheops approach maintains context within a huge hierarchy, while simultaneously providing easy access to details. This paper will also present some preliminary results from usability tests performed on an 8 wide by 9 deep classification hierarchy, which if fully populated would contain over 19 million nodes.}, doi = {10.1109/VISUAL.1996.567745}, year = {1996}, booktitle = {Visualization'96: Proceedings of the IEEE Conference on Visualization}, editor = {Roni Yagel and Gregory M. Nielson}, publisher = {ACM Press}, isbn = {0897918649} } @INPROCEEDINGS{Beck2014, author = {Fabian Beck and Michael Burch and Tanja Munz and Lorenzo Di Silvestro and Daniel Weiskopf}, title = {Generalized {Pythagoras Trees} for Visualizing Hierarchies}, pages = {17--28}, abstract = {Pythagoras Trees are fractals that can be used to depict binary hierarchies. But this binary encoding is an obstacle for visualizing hierarchical data such as file systems or phylogenetic trees, which branch into n subhierarchies. Although any hierarchy can be modeled as a binary one by subsequently dividing n-ary branches into a sequence of n-1 binary branches, we follow a different strategy. In our approach extending Pythagoras Trees to arbitrarily branching trees, we only need a single visual element for an n-ary branch instead of spreading the binary branches along a strand. Each vertex in the hierarchy is visualized as a rectangle sized according to a metric. We analyze several visual parameters such as length, width, order, and color of the nodes against the use of different metrics. The usefulness of our technique is illustrated by two case studies visualizing directory structures and a large phylogenetic tree. We compare our approach with existing tree diagrams and discuss questions of geometry, perception, readability, and aesthetics.}, doi = {10.5220/0004654500170028}, year = {2014}, booktitle = {IVAPP'14: Proceedings of the International Conference on Information Visualization Theory and Applications}, editor = {Robert S. Laramee and Andreas Kerren and Jos\'e Braz}, publisher = {SCITEPRESS}, isbn = {9789897580055} } @INPROCEEDINGS{Beck2015, author = {Fabian Beck and Michael Burch and Tanja Munz and Lorenzo Di Silvestro and Daniel Weiskopf}, title = {Generalized {Pythagoras Trees}: A fractal approach to hierarchy visualization}, pages = {115--135}, abstract = {Through their recursive definition, many fractals have an inherent hierarchical structure. An example are binary branching Pythagoras Trees. By stopping the recursion in certain branches, a binary hierarchy can be encoded and visualized. But this binary encoding is an obstacle for representing general hierarchical data such as file systems or phylogenetic trees, which usually branch into more than two subhierarchies. We hence extend Pythagoras Trees to arbitrarily branching trees by adapting the geometry of the original fractal approach. Each vertex in the hierarchy is visualized as a rectangle sized according to a metric. We analyze several visual parameters such as length, width, order, and color of the nodes against the use of different metrics. Interactions help to zoom, browse, and filter the hierarchy. The usefulness of our technique is illustrated by two case studies visualizing directory structures and a large phylogenetic tree. We compare our approach with existing tree diagrams and discuss questions of geometry, perception, readability, and aesthetics.}, doi = {10.1007/978-3-319-25117-2_8}, year = {2015}, booktitle = {Computer Vision, Imaging and Computer Graphics -- Theory and Applications, Revised Selected Papers of the International Conference VISIGRAPP 2014}, editor = {Sebastiano Battiato and Sabine Coquillart and Julien Pettr\'e and Robert S. Laramee and Andreas Kerren and Jos\'e Braz}, publisher = {Springer}, series = {Communications in Computer and Information Science}, isbn = {9783319251165} } @INPROCEEDINGS{Bederson2001, author = {Benjamin B. Bederson}, title = {{PhotoMesa}: A Zoomable Image Browser Using Quantum Treemaps and Bubblemaps}, pages = {71--80}, abstract = {PhotoMesa is a zoomable image browser that uses a novel treemap algorithm to present large numbers of images grouped by directory, or other available metadata. It uses a new interaction technique for zoomable user interfaces designed for novices and family use that makes it straightforward to navigate through the space of images, and impossible to get lost. PhotoMesa groups images using one of two new algorithms that lay out groups of objects in a 2D space-filling manner. Quantum treemaps are designed for laying out images or other objects of indivisible (quantum) size. They are a variation on existing treemap algorithms in that they guarantee that every generated rectangle will have a width and height that are an integral multiple of an input object size. Bubblemaps also fill space with groups of quantum-sized objects, but generate non-rectangular blobs, and utilize space more efficiently.}, doi = {10.1145/502348.502359}, year = {2001}, booktitle = {UIST'01: Proceedings of the Annual ACM Symposium on User Interface Software and Technology}, editor = {Marks, Joe and Mynatt, Elizabeth D.}, publisher = {ACM Press}, isbn = {158113438X} } @ARTICLE{Bederson2002, author = {Benjamin B. Bederson and Ben Shneiderman and Martin Wattenberg}, title = {Ordered and quantum treemaps: Making effective use of {2D} space to display hierarchies}, journal = {ACM Transactions on Graphics}, year = {2002}, volume = {21}, pages = {833--854}, number = {4}, abstract = {Treemaps, a space-filling method for visualizing large hierarchical data sets, are receiving increasing attention. Several algorithms have been previously proposed to create more useful displays by controlling the aspect ratios of the rectangles that make up a treemap. While these algorithms do improve visibility of small items in a single layout, they introduce instability over time in the display of dynamically changing data, fail to preserve order of the underlying data, and create layouts that are difficult to visually search. In addition, continuous treemap algorithms are not suitable for displaying fixed-sized objects within them, such as images.This paper introduces a new "strip" treemap algorithm which addresses these shortcomings, and analyzes other "pivot" algorithms we recently developed showing the trade-offs between them. These ordered treemap algorithms ensure that items near each other in the given order will be near each other in the treemap layout. Using experimental evidence from Monte Carlo trials and from actual stock market data, we show that, compared to other layout algorithms, ordered treemaps are more stable, while maintaining relatively favorable aspect ratios of the constituent rectangles. A user study with 20 participants clarifies the human performance benefits of the new algorithms. Finally, we present quantum treemap algorithms, which modify the layout of the continuous treemap algorithms to generate rectangles that are integral multiples of an input object size. The quantum treemap algorithm has been applied to PhotoMesa, an application that supports browsing of large numbers of images.}, doi = {10.1145/571647.571649} } @INPROCEEDINGS{Beermann2005, author = {Dale Beermann and Tamara Munzner and Greg Humphreys}, title = {Scalable, Robust Visualization of Very Large Trees}, pages = {37--44}, abstract = {The TreeJuxtaposer system allowed visual comparison of large trees with guaranteed visibility of landmarks and Focus+Context navigation. While that system allowed exploration and comparison of larger datasets than previous work, it was limited to a single tree of 775,000 nodes by a large memory footprint. In this paper, we describe the theoretical limitations to TreeJuxtaposer's architecture that severely restrict its scalability. We provide two scalable, robust solutions to these limitations: TJC and TJC-Q. TJC is a system that supports browsing trees up to 15 million nodes by exploiting leading-edge graphics hardware while TJC-Q allows browsing trees up to 5 million nodes on commodity platforms. Both of these systems use a fast new algorithm for drawing and culling and benefit from a complete redesign of all data structures for more efficient memory usage and reduced preprocessing time.}, doi = {10.2312/VisSym/EuroVis05/037-044}, year = {2005}, booktitle = {EuroVis'05: Proceedings of the Joint Eurographics - IEEE VGTC Symposium on Visualization}, editor = {Ken Brodlie and David Duke and Kenneth I. Joy}, publisher = {Eurographics Association}, isbn = {3905673193} } @INPROCEEDINGS{Bein2000, author = {Wolfgang W. Bein and Lawrence L. Lamore and Shields, Jr., Charles O. and Ivan Hal Sudborough}, title = {Three-dimensional embedding of binary trees}, pages = {140--147}, abstract = {We describe total congestion 1 embeddings of complete binary trees into three dimensional grids with expansion ratios 1.172 and 1.25. That is, we give a one-to-one embedding of any complete binary tree into a hexahedron shaped grid such that: the number of nodes in the grid is at most 1.172 (1.25) times the number of nodes in the tree; and no tree nodes or edges occupy the same grid positions. The first strategy embeds trees into cube shaped 3D grids. That is, 3D grids in which all dimensions are roughly equal in size. The second strategy embeds trees into flat 3D grid shapes. That is, it maps complete binary trees into 3D grids with a fixed, small number of layers. An application suggests which embedding to use. For simulations in parallel computer environments, or possibly graph drawing, a cube shaped 3D grid is appropriate. For the sake of VLSI, or other graph drawing applications, embeddings with a small number of layers are better.}, doi = {10.1109/ISPAN.2000.900278}, year = {2000}, booktitle = {I-SPAN'00: Proceedings of the International Symposium on Parallel Architectures, Algorithms and Networks}, editor = {Hal Sudborough and Burkhard Monien and D. Frank Hsu}, publisher = {IEEE Computer Society}, isbn = {0769509363} } @ARTICLE{Bein2004, author = {Wolfgang W. Bein and Lawrence L. Lamore and Shields, Jr., Charles O. and Ivan Hal Sudborough}, title = {Embedding a complete binary tree into a three-dimensional grid}, journal = {Journal of Interconnection Networks}, year = {2004}, volume = {5}, pages = {111--130}, number = {2}, abstract = {We describe total congestion 1 embeddings of complete binary trees into three dimensional grids with low expansion ratio r. That is, we give a one-to-one embedding of any complete binary tree into a hexahedron shaped grid such that (a) the number of nodes in the grid is at most r times the number of nodes in the tree, and (b) no tree nodes or edges occupy the same grid positions. The first strategy embeds trees into cube shaped 3D grids. That is, 3D grids in which all dimensions are roughly equal in size, and which thus have no limit in the number of layers. The technique uses a recursive scheme, and we obtain an expansion ratio of r=1.09375. We then give strategies which embed trees into flat 3D grid shapes. That is, we map complete binary trees into 3D grids with a fixed, small number of layers k. Using again a recursive scheme, for k=2, we obtain r=1.25. By a rather different technique, which intricately weaves the branches of various subtrees into each other, we are able to obtain very tight embeddings: We have r=1.171875 for embeddings into five layer grids and r=1.09375 for embeddings into seven layer grids.}, doi = {10.1142/S0219265904001052} } @INPROCEEDINGS{Benson2010, author = {Jordan Riley Benson and Lee Sullvan and Rajiv Ramarajan and Frank Wimmer and Paul Hankey}, title = {Using Orthographic Projection and Animation to Convey Treemap Structure}, abstract = {We present an alternative treemap visualization method that maintains the space-filling and area comparison benefits of the standard treemap while improving the range of possible comparisons and the clarity of the hierarchy. Our visualization uses an orthographic stack representation and relies on interaction and animation to reveal the structure of the treemap to the user, but is still effective in a static environment once the user reaches a view that interests them.}, url = {http://blogs.sas.com/peerrevue/uploads/OrthographicTreeMap-summary.pdf}, year = {2010}, booktitle = {InfoVis'10: Poster at the IEEE Conference on Information Visualization} } @PATENT{Bereiter1999, author = {Thomas William Bereiter and Doron Gan}, title = {Method and apparatus for the viewing and exploration of the content of hierarchical information}, number = {US 5917492}, year = {1999}, abstract = {A method and system are disclosed for displaying a graphical representation on a display screen of a data processing system in a manner that optimizes screen "real estate" and ease of information viewing. The graphical representation may be a tree hierarchy including a plurality of expandable and collapsible nodes. The method begins as the hierarchy is displayed within a primary display window on the display screen when the user selects a node to be expanded . In response, a first display region is output within the primary display window and includes a set of one or more subnodes associated with the selected node. If a first subnode in the first display region is then selected for expansion, a second display region is then output within the first display region, and the second display region in turn includes a set of one or more subnodes of the first subnode. This generation of new "nested" display regions then continues as the user continues to explore deeper into the tree hierarchy. A given subnode display region may have one or more controls, such as a sizing button or one or more scroll bars, to facilitate display of node information within the region, and preferably each expanded node remains associated with its subnode display region using a guideline. If generation and display of a subnode display region requires additional screen space, one or more of the subnodes in the "parent" display region are re-positioned.}, url = {http://www.freepatentsonline.com/5917492.html} } @INPROCEEDINGS{Berg2011, author = {Mark de Berg and Bettina Speckmann and Vincent van der Weele}, title = {Treemaps with Bounded Aspect Ratio}, pages = {260--270}, abstract = {Treemaps are a popular technique to visualize hierarchical data. The input is a weighted tree T where the weight of each node is the sum of the weights of its children. A treemap for T is a hierarchical partition of a rectangle into simply connected regions, usually rectangles. Each region represents a node of T and its area is proportional to the weight of the corresponding node. An important quality criterion for treemaps is the aspect ratio of its regions. One cannot bound the aspect ratio if the regions are restricted to be rectangles. In contrast, polygonal partitions, that use convex polygons, can have bounded aspect ratio. We are the first to obtain convex partitions with optimal aspect ratio O(depth(T)) . However, depth(T) still depends on the input tree. Hence we introduce a new type of treemaps, namely orthoconvex treemaps, where regions representing leaves are rectangles, L-, and S-shapes, and regions representing internal nodes are orthoconvex polygons. We prove that any input tree, irrespective of the weights of the nodes and the depth of the tree, admits an orthoconvex treemap of constant aspect ratio.}, doi = {10.1007/978-3-642-25591-5_28}, year = {2011}, booktitle = {ISAAC'11: Proceedings of the International Symposium on Algorithms and Computations}, editor = {Takao Asano and Shin-ichi Nakano and Yoshio Okamoto and Osamu Watanabe}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642255908}, } @ARTICLE{Berg2011a, author = {Mark de Berg and Bettina Speckmann and Vincent van der Weele}, title = {Treemaps with Bounded Aspect Ratio}, journal = {arXiv.org e-print service}, year = {2011}, volume = {1012.1749v2}, abstract = {Treemaps are a popular technique to visualize hierarchical data. The input is a weighted tree $\tree$ where the weight of each node is the sum of the weights of its children. A treemap for $\tree$ is a hierarchical partition of a rectangle into simply connected regions, usually rectangles. Each region represents a node of $\tree$ and the area of each region is proportional to the weight of the corresponding node. An important quality criterium for treemaps is the aspect ratio of its regions. Unfortunately, one cannot bound the aspect ratio if the regions are restricted to be rectangles. Hence Onak and Sidiropoulos in SoCG 2008 introduced \emph{polygonal partitions}, which use convex polygons. We are the first to obtain convex partitions with optimal aspect ratio $O(\depth(\tree))$. Furthermore, we consider rectilinear partitions, which retain more of the schematized flavor of standard rectangular treemaps. Our rectilinear treemaps have constant aspect ratio, independent of $\depth(\tree)$ or the number and weight of the nodes. The leaves of $\tree$ are represented by rectangles, L-, and S-shapes and internal nodes by orthoconvex polygons. We also consider the important special case that $\depth(\tree)=1$, that is, single-level treemaps. We prove that it is strongly NP-hard to minimize the aspect ratio of a rectangular single-level treemap. On the positive side we show how to construct rectilinear and convex single-level treemaps with constant aspect ratio. Our rectilinear single-level treemaps use only rectangles and L-shapes and have aspect ratio at most $2 + 2 \sqrt{3}/3$. The convex version uses four different octilinear shapes and has aspect ratio at most 9/2.}, url = {http://arxiv.org/abs/1012.1749v2} } @INPROCEEDINGS{Berg2011b, author = {Mark de Berg and Bettina Speckmann and Vincent van der Weele}, title = {{Convex Treemaps} with Bounded Aspect Ratio}, pages = {71--74}, abstract = {Treemaps are a popular technique to visualize hierarchical data. The input is a weighted tree T where the weight of each node is the sum of the weights of its children. A treemap for T is a hierarchical partition of a rectangle into simply connected regions, usually rectangles. Each region represents a node of T and the area of each region is proportional to the weight of the corresponding node. An important quality criterium for treemaps is the aspect ratio of its regions. Unfortunately, one cannot bound the aspect ratio if the regions are restricted to be rectangles. Hence Onak and Sidiropoulos introduced polygonal partitions, which use convex polygons. We are the first to obtain convex partitions with optimal aspect ratio O(depth(T)). We also consider the important special case that depth(T)=1, that is, single-level treemaps. We show how to construct convex single-level treemaps that use only four simple shapes for the regions and have aspect ratio at most 34/7.}, url = {http://eurocg11.inf.ethz.ch/abstracts/62.pdf}, year = {2011}, booktitle = {EuroCG'11: Book of Abstracts of the European Workshop on Computational Geometry} } @ARTICLE{Berg2013, author = {Mark de Berg and Krzysztof Onak and Anastasios Sidiropoulos}, title = {Fat Polygonal Partitions with Applications to Visualization and Embeddings}, journal = {Journal of Computational Geometry}, year = {2013}, volume = {14}, pages = {212--239}, number = {1}, abstract = {Let T be a rooted and weighted tree, where the weight of any node is equal to the sum of the weights of its children. The popular Treemap algorithm visualizes such a tree as a hierarchical partition of a square into rectangles, where the area of the rectangle corresponding to any node in T is equal to the weight of that node. The aspect ratio of the rectangles in such a rectangular partition necessarily depends on the weights and can become arbitrarily high. We introduce a new hierarchical partition scheme, called a polygonal partition, which uses convex polygons rather than just rectangles. We present two methods for constructing polygonal partitions, both having guarantees on the worst-case aspect ratio of the constructed polygons; in particular, both methods guarantee a bound on the aspect ratio that is independent of the weights of the nodes. We also consider rectangular partitions with slack, where the areas of the rectangles may differ slightly from the weights of the corresponding nodes. We show that this makes it possible to obtain partitions with constant aspect ratio. This result generalizes to hyper-rectangular partitions in $R^d$. We use these partitions with slack for embedding ultrametrics into d-dimensional Euclidean space: we give a polylog(delta)-approximation algorithm for embedding n-point ultrametrics into $R^d$ with minimum distortion, where delta denotes the spread of the metric. The previously best-known approximation ratio for this problem was polynomial in n. This is the first algorithm for embedding a non-trivial family of weighted-graph metrics into a space of constant dimension that achieves polylogarithmic approximation ratio.}, url = {http://jocg.org/index.php/jocg/article/view/74} } @INPROCEEDINGS{Bernhardt2009, author = {J\"org Bernhardt and Stefan Funke and Michael Hecker and Juliane Siebourg}, title = {Visualizing Gene Expression Data via Voronoi Treemaps}, pages = {233--241}, abstract = {We investigate the use of Voronoi Treemaps to visualize complex biological data from gene expression analysis in conjunction with hierarchical classifications like Gene Ontology or KEGG Orthology.}, doi = {10.1109/ISVD.2009.33}, year = {2009}, booktitle = {ISVD'09: Proceedings of the International Symposium on Voronoi Diagrams}, editor = {Fran\c{c}ois Anton}, publisher = {IEEE Computer Society}, isbn = {9780769537818} } @INPROCEEDINGS{Bernstein2000, author = {Rocky Bernstein}, title = {{xps} -- Dynamic Process Tree Watching Under {X}}, pages = {95--100}, abstract = {The xps program dynamically displays the Unix processes as a tree or forest in an X Window, the roots on the left and the leaf processes (those with no children) on the right. The status of each process running, sleeping, stopped, etc., can be indicated by different colors. Different users can appear as different colors too. Process selection can be made per user, all users, or through a regular-expression pattern. In contrast to the terminal-based pstree or tree-widget based programs, the tree display uses diagonal lines, and effort is made to effectively use the full 2-dimensional area of the screen by balancing levels and centering the children of a node between their parent. A goal of the program is to give an idea of what's going on graphically as things may be constantly changing. Therefore the display algorithm tries to keep processes close to their parents to reduce the amount of scrolling to see localized process creation and destruction. Some effort is also given to make sure that the tree layout doesn't get wildly reorganized when there are small or localized changes. This makes it easier for the eye to pick up and recognize the changes over a potentially large display area. We describe here criteria for tree animations such as this one and how the xps layout algorithm works. There are some other miscellaneous features of xps. One can select viewing the processes by a single user, a regular expression for users, by all users, and perhaps show kernel processes. One can click on a process to get more information (via ps or a user-specified program) about that process, send a signal, or set the process priority, assuming you have the permission to do so. Since programs of this ilk can consume a bit of CPU on their own, some effort has been made to turn off the update process when the program is iconified or not visible for some other reason such as being obscured by another window. Some attention has been paid to make algorithm display fairly fast in most situations, although it has to be admitted that this comes sometimes at the expense of a nicer layout.}, url = {http://www.usenix.org/events/lisa00/bernstein.html}, year = {2000}, booktitle = {LISA'00: Proceedings of the Large Installation System Administration Conference} } @BOOK{Bertin1967, title = {Semiologie graphique. Les diagrammes, les reseaux, les cartes}, publisher = {Editions Gauthier-Villars}, year = {1967}, author = {Jacques Bertin}, abstract = {Jacques Bertin a joue un role majeur dans l'evolution des conceptions graphiques et cartographiques. Semiologie graphique est l'un de ses ouvrages incontournables, plusieurs fois reedite et traduit en anglais. Cette nouvelle edition propose une carte hors texte offrant une vision saisissante du relief de la France. Elle comporte egalement des mises au point originales de Jacques Bertin et constitue une synthese de ses demarches. Semiologie graphique apporte une reponse objective aux deux questions suivantes: dans quel cas faut-il faire un dessin? Quel dessin faut-il faire? La semiologie graphique remplace l'inventaire classique des formules graphiques par une analyse des moyens et des buts et par un ensemble de regles imperatives qui commandent la redaction graphique, c'est-a-dire le choix des correspondances entre les sensibilites visuelles disponibles et les elements de l'information.} } @BOOK{Bertin1981, title = {Graphics and Graphic Information Processing}, publisher = {Walter de Gruyter}, year = {1981}, author = {Jacques Bertin}, isbn = {3110088681}, doi = {10.1515/9783110854688} } @BOOK{Bertin1984, title = {Semiology of graphics: Diagrams, networks, maps}, publisher = {University of Wisconsin Press}, year = {1984}, author = {Jacques Bertin}, isbn = {0299090604}, abstract = {Originally published in French in 1967, Semiology of Graphics is internationally recognized as a foundational work in the fields of design and cartography. Based on Jacques Bertin's practical experience as a cartographer, part one of this work is an unprecedented attempt to synthesize principles of graphic communication with the logic of standard rules applied to writing and topography. Part two brings Bertin's theory to life, presenting a close study of graphic techniques, including shape, orientation, color, texture, volume, and size, in an array of more than 1,000 maps and diagrams. Now, with a new epilogue written by the author shortly before his death, this new 2010 edition in English reawakens us to the information design possibilities of modern technology. Jacques Bertin was a French cartographer and theorist, and a world renowned authority on the subject of information visualization. In 1954, he founded the Cartographic Laboratory of the Ecole Pratique des Hautes Etudes, and in 1957 he was named director of education. In 1967, Bertin became a professor at the Sorbonne, and in 1974 he was appointed director of education and director of the Geographical Laboratory of the Ecole des Hautes Etudes en Sciences Sociales. In the late 1970s, he became head of research at the Centre National de la Recherche Scientifique.} } @INPROCEEDINGS{Bethge2017, author = {Joseph Bethge and Sebastian Hahn and J\"urgen D\"ollner}, title = {Improving Layout Quality by Mixing {T}reemap-Layouts Based on Data-Change Characteristics}, pages = {69--76}, abstract = {This paper presents a hybrid treemap layout approach that optimizes layout-quality metrics by combining state-of-the-art treemap layout algorithms. It utilizes machine learning to predict those metrics based on data metrics describing the characteristics and changes of the dataset. For this, the proposed approach uses a neural network which is trained on artificially generated dataset,s containing a total of 15.8 million samples. The resulting model is integrated into an approach called Smart- Layouting. This approach is evaluated on real-world data from 100 publicly available software repositories. Compared to other state-of-the-art treemap algorithms it reaches an overall better result. Additionally, this approach can be customized by an end user's needs. The customization allows for specifying weights for the importance of each layout-quality metric. The results indicate, that the algorithm is able to adapt successfully towards a given set of weights.}, doi = {10.2312/vmv.20171261}, year = {2017}, booktitle = {VMV'17: Proceedings of the International Symposium on Vision, Modeling and Visualization}, editor = {Matthias Hullin and Reinhard Klein and Thomas Schultz and Angela Yao}, publisher = {Eurographics Association}, isbn = {9783038680499} } @ARTICLE{Bhattacharya1994, author = {Sourav Bhattacharya and Wei-Tek Tsai}, title = {Recursive binary tree layout mixing}, journal = {Information Sciences}, year = {1994}, volume = {77}, pages = {39--49}, number = {1-2}, abstract = {Binary tree layout with adequate boundary-I/O has been approached by mixing the H-layout and standard layout patterns. This paper proposes a recursive method of mixing these two tree layout patterns. Unlike the existing technique (of using a single continuous stretch of H-layout and then standard layout for the remaining tree levels), we propose to mix these two layout styles in a finer grain. The finer grain mixed pattern is then repeated to obtain an overall tree layout. This approach offers an order of area improvement over the existing single stretch layout mixing approaches, while retaining identical boundary-I/O. This makes the proposed approach an order of magnitude superior to the existing techniques.}, doi = {10.1016/0020-0255(94)90047-7} } @INPROCEEDINGS{Bisson2012, author = {Gilles Bisson and Renaud Blanch}, title = {Stacked trees: a new hybrid visualization method}, pages = {709--712}, abstract = {In this paper, we introduce a new Focus+Context visualization technique, named ``Stacked Trees'', allowing us to explore large dendrograms produced by hierarchical clustering. This approach displays up to fifty thousands nodes on a standard-sized screen.}, doi = {10.1145/2254556.2254690}, year = {2012}, booktitle = {AVI'12: Proceedings of the Working Conference on Advanced Visual Interfaces}, editor = {Genny Tortora and Stefano Levialdi and Maurizio Tucci}, publisher = {ACM Press}, isbn = {9781450312875} } @INPROCEEDINGS{Bisson2012a, author = {Gilles Bisson and Renaud Blanch}, title = {Improving Visualization of Large Hierarchical Clustering}, pages = {220--228}, abstract = {The classical representation of a binary tree generated by a hierarchical clustering is a node-link-based visualization denoted as a dendrogram. It allows users to explore in a simple way the clusters and the relationships between instances. However, exploration of large dendrograms is known to be difficult due to the graphical and cognitive information overload involved. Here, we discuss the current approaches and we introduce Stacked Trees, a new Focus+Context visualization technique that allows the exploration of the hierarchical clustering of up to fifty thousands nodes on a standard-sized screen.}, doi = {10.1109/IV.2012.45}, year = {2012}, booktitle = {IV'12: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Stefan Bertschi and Camilla Forsell and Jimmy Johansson and Sarah Kenderdine and Francis T. Marchese and Muhammad Sarfraz and Liz Stuart and Anna Ursyn and Theodor G. Wyeld and Hanane Azzag and Mustapha Lebba and Gilles Venturini}, publisher = {IEEE Computer Society}, isbn = {9780769547718} } @INPROCEEDINGS{Bladh2004, author = {Thomas Bladh and David A. Carr and Jeremiah Scholl}, title = {Extending Tree-Maps to Three Dimensions: A Comparative Study}, pages = {50--59}, abstract = {This paper presents StepTree, an information visualization tool designed for depicting hierarchies, such as directory structures. StepTree is similar to the hierarchy-visualization tool, Treemap, in that it uses a rectangular, space-filling methodology, but differs from Treemap in that it employs three-dimensional space, which is used to more clearly convey the structural relationships of the hierarchy. The paper includes an empirical study comparing typical search and analysis tasks using StepTree and Treemap. The study shows that users perform significantly better on tasks related to interpreting structural relationships when using StepTree. In addition, users achieved the same performance with StepTree and Treemap when doing a range of other common interpretative and navigational tasks.}, doi = {10.1007/978-3-540-27795-8_6}, year = {2004}, booktitle = {APCHI'04: Proceedings of the Asia Pacific Conference on Computer Human Interaction}, editor = {Masood Masoodian and Steve Jones and Bill Rogers}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540223122}, } @INPROCEEDINGS{Bladh2005, author = {Thomas Bladh and David A. Carr and Matja\v{z} Kljun}, title = {The effect of animated transitions on user navigation in {3D Tree-maps}}, year = {2005}, pages = {297--305}, abstract = {This paper describes a user study conducted to evaluate the use of smooth animated transitions between directories in a three-dimensional, tree-map visualization. We looked specifically at the task of returning to a previously visited directory after either an animated or instantaneous return to the root location. The results of the study show that animation is a double-edged sword. Even though users take more shortcuts, they also make more severe navigational errors. It seems as though the promise of a more direct route to the target directory, which animation provides, somehow precludes users who navigate incorrectly from applying a successful recovery strategy.}, doi = {10.1109/IV.2005.122}, year = {2005}, booktitle = {IV'05: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Muhammad Sarfraz and Jonathan C. Roberts and Bowen Loften and Anna Ursyn and Remo Aslak Burkhard and Angela Lee and Gennady Andrienko}, publisher = {IEEE Computer Society}, isbn = {0769523978} } @INPROCEEDINGS{Blanch2006, author = {Renaud Blanch and \'Eric Lecolinet}, title = {Navigation Techniques for {Zoomable Treemaps}}, pages = {49--50}, abstract = {This paper presents a new technique called zoomable treemaps that makes it possible to navigate in very large trees. It integrates several efficient interaction techniques that enable multi-scale and structure-aware navigation.}, url = {http://www.acm.org/uist/archive/adjunct/2006/pdf/demos/p49-blanch.pdf}, year = {2006}, booktitle = {UIST'06: Adjunct Proceedings of the Annual ACM Symposium on User Interface Software and Technology}, publisher = {ACM Press}, isbn = {1595933131} } @ARTICLE{Blanch2007, author = {Renaud Blanch and \'Eric Lecolinet}, title = {Browsing {Zoomable Treemaps}: Structure-Aware Multi-Scale Navigation Techniques}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2007}, volume = {13}, pages = {1248--1253}, number = {6}, abstract = {Treemaps provide an interesting solution for representing hierarchical data. However, most studies have mainly focused on layout algorithms and paid limited attention to the interaction with treemaps. This makes it difficult to explore large data sets and to get access to details, especially to those related to the leaves of the trees. We propose the notion of zoomable treemaps (ZTMs), an hybridization between treemaps and zoomable user interfaces that facilitates the navigation in large hierarchical data sets. By providing a consistent set of interaction techniques, ZTMs make it possible for users to browse through very large data sets (e.g., 700,000 nodes dispatched amongst 13 levels). These techniques use the structure of the displayed data to guide the interaction and provide a way to improve interactive navigation in treemaps.}, doi = {10.1109/TVCG.2007.70540} } @INPROCEEDINGS{Blanch2007a, author = {Renaud Blanch and \'Eric Lecolinet}, title = {Treemaps zoomables: techniques d'interaction multi-\'echelles pour les treemaps}, pages = {131--138}, abstract = {Some efficient visualizations (such as treemaps) have been proposed for trees, but the interaction they provide to explore and acces data is often poor, especially for very large trees. We have designed a consistent set of navigation techniques that makes it possible to use treemaps as zoomable interfaces. We introduce structure-aware navigation, the property of using the structure of the displayed information to guide navigation, property that our interaction techniques share.}, doi = {10.1145/1541436.1541462}, year = {2007}, booktitle = {IHM'07: Proceedings of the International Conference on Association Francophone d'Interaction Homme-Machine}, editor = {Carlos Agon and Olivier Delerue}, publisher = {ACM Press}, isbn = {9781595937919} } @INPROCEEDINGS{Blanch2015, author = {Renaud Blanch and R\'emy Dautriche and Gilles Bisson}, title = {Dendrogramix: A hybrid tree-matrix visualization technique to support interactive exploration of dendrograms}, pages = {31--38}, abstract = {Clustering is often a first step when trying to make sense of a large data set. A wide family of cluster analysis algorithms, namely hierarchical clustering algorithms, does not provide a partition of the data set but a hierarchy of clusters organized in a binary tree, known as a dendrogram. The dendrogram has a classical node-link representation used by experts for various tasks like: to decide which subtrees are actual clusters (e.g., by cutting the dendrogram at a given depth); to give those clusters a name by inspecting their content; etc. We present Dendrogramix, a hybrid tree-matrix interactive visualization of dendrograms that superimposes the relationship between individual objects on to the hierarchy of clusters. Dendrogramix enables users to do tasks which involve both clusters and individual objects that are impracticable with the classical representation, like: to explain why a particular objects belongs to a particular cluster; to elicit and understand uncommon patterns (e.g., objects that could have been classified in a totally different cluster); etc. Those sensemaking tasks are supported by a consistent set of interaction techniques that facilitates the exploration of large clustering results.}, doi = {10.1109/PACIFICVIS.2015.7156353}, year = {2015}, booktitle = {PacificVis'15: Proceedings of the IEEE Pacific Visualization Symposium}, editor = {Shixia Liu and Gerik Scheuermann and Shigeo Takahashi}, publisher = {IEEE Computer Society}, isbn = {9781467368797} } @ARTICLE{Block2012, author = {Florian Block and Michael S. Horn and Brenda Caldwell Phillips and Judy Diamond and E. Margaret Evans and Chia Shen}, title = {The {DeepTree} Exhibit: Visualizing the {Tree of Life} to Facilitate Informal Learning}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2012}, volume = {18}, pages = {2789--2798}, number = {12}, abstract = {In this paper, we present the DeepTree exhibit, a multi-user, multi-touch interactive visualization of the Tree of Life. We developed DeepTree to facilitate collaborative learning of evolutionary concepts. We will describe an iterative process in which a team of computer scientists, learning scientists, biologists, and museum curators worked together throughout design, development, and evaluation. We present the importance of designing the interactions and the visualization hand-in-hand in order to facilitate active learning. The outcome of this process is a fractal-based tree layout that reduces visual complexity while being able to capture all life on earth; a custom rendering and navigation engine that prioritizes visual appeal and smooth fly-through; and a multi-user interface that encourages collaborative exploration while offering guided discovery. We present an evaluation showing that the large dataset encouraged free exploration, triggers emotional responses, and facilitates visitor engagement and informal learning.}, doi = {10.1109/TVCG.2012.272} } @TECHREPORT{Block2012a, author = {Florian Block and Michael S. Horn and Brenda Caldwell Phillips and Judy Diamond and E. Margaret Evans and Chia Shen}, title = {Technical appendix: The DeepTree layout and rendering engine}, institution = {Harvard University}, year = {2012}, abstract = {This technical report provides details regarding the DeepTree layout and rendering engine}, url = {https://lifeonearth.seas.harvard.edu/downloads/DeepTree.pdf} } @ARTICLE{Bloesch1993, author = {Anthony Bloesch}, title = {Aesthetic layout of generalized trees}, journal = {Software: Practice and Experience}, year = {1993}, volume = {23}, pages = {817--827}, number = {8}, abstract = {Research on the aesthetic layout of trees has been largely concerned with the special case of binary trees with small constant-sized nodes. Yet, without otherwise requiring the power of general graph-layout algorithms, many layout problems involve n-ary trees with variable-sized nodes. This paper addresses the general issue of the aesthetic layout of such trees. Two algorithms are presented for the layout of generalized trees, and general issues, such as appropriate aesthetics, are discussed. The algorithms described are suitable for such tasks as the layout of class hierarchies, directory trees and tableau-style proofs.}, doi = {10.1002/spe.4380230802} } @INPROCEEDINGS{Boardman2000, author = {Richard Boardman}, title = {{Bubble Trees} -- The visualization of hierarchical information structures}, pages = {315--316}, abstract = {A tree visualization mechanism is proposed, based on the natural property of trees to recursively sub-categorize themselves into sub-trees. Each sub-tree is graphically represented as a bubble, which aggregates detail by enclosing lower-level information. Navigation and information retrieval are facilitated through an elegant set of browsing interactions. The interface is useful for tasks where users are required to develop a mental model of a classification system. The interactive nature of bubble trees allows users to explore and work out relationships for themselves.}, doi = {10.1145/633292.633484}, year = {2000}, booktitle = {CHI'00: Extended abstracts of the SIGCHI conference on Human Factors in Computing Systems}, publisher = {ACM Press}, isbn = {1581132484} } @MISC{Bocoup2011, author = {Bocoup}, title = {Newsweek Career Tree Visualization with {RaphaelJS} and {Burst}}, url = {http://weblog.bocoup.com/newsweek-raphaeljs-career-tree-visualization-raphaeljs-burst/}, year = {2011}, note = {retrieved 27-SEPT-2012}, abstract = {Career Tree is a vector based RaphaelJS/Burst visualization of your career - you can activate it by connecting with your LinkedIn account or by filling out a Career Tree form.} } @INPROCEEDINGS{Bohanec2007, author = {Marko Bohanec}, title = {{DEXiTree}: A program for pretty drawing of trees}, pages = {7--10}, abstract = {This paper presents DEXiTree, a computer program for drawing trees. In principle, DEXiTree is aimed at making nice drawings of attribute trees made by DEXi, a computer program for qualitative multi-attribute decision modelling. Apart from that, DEXiTree is quite a general and powerful tree-drawing program that implements four different tree-drawing algorithms (called Distribute, Align, Walker, and QP), draws trees in four different directions (top-down, left-right, bottom-up and right-left) and provides an extensive set of parameters for controlling the appearance of trees and their components. DEXiTree’s functionality includes loading a decision model from a DEXi file, interactively designing the tree layout, saving and loading the layout using an XML format, and rendering the drawing in two graphic formats: vector and raster.}, url = {http://kt.ijs.si/MarkoBohanec/pub/IS2007_DEXiTree.pdf}, year = {2007}, booktitle = {IS'07: Proceedings of the International Multiconference Information Society}, editor = {Marko Bohanec and Matja\v{z} Gams and Vladislav Rajkovi\v{c} and Tanja Urban\v{c}i\v{c} and Mojca Bernik and Dunja Mladeni\'c and Marko Grobelnik and Marjan Heri\v{c}ko and Urban Korde\v{s} and Olga Marki\v{c}}, isbn = {9789616303941}, } @BOOK{Bohnacker2012, title = {Generative Design}, publisher = {Princeton Architectural Press}, year = {2012}, editor = {Claudius Lazzeroni}, author = {Hartmut Bohnacker and Benedikt Gross and Julia Laub}, isbn = {9781616890773}, abstract = {Generative design is a revolutionary new method of creating artwork, models, and animations from sets of rules, or algorithms. By using accessible programming languages such as Processing, artists and designers are producing extravagant, crystalline structures that can form the basis of anything from patterned textiles and typography to lighting, scientific diagrams, sculptures, films, and even fantastical buildings. Opening with a gallery of thirty-five illustrated case studies, Generative Design takes users through specific, practical instructions on how to create their own visual experiments by combining simple-to-use programming codes with basic design principles. A detailed handbook of advanced strategies provides visual artists with all the tools to achieve proficiency. Both a how-to manual and a showcase for recent work in this exciting new field, Generative Design is the definitive study and reference book that designers have been waiting for.} } @ARTICLE{Bouckaert2010, author = {Remco R. Bouckaert}, title = {{DensiTree}: Making sense of sets of phylogenetic trees}, journal = {Bioinformatics}, year = {2010}, volume = {26}, pages = {1372--1373}, number = {10}, abstract = {Bayesian analysis through programs like BEAST (Drummond and Rumbaut, 2007) and MrBayes (Huelsenbeck et al., 2001) provides a powerful method for reconstruction of evolutionary relationships. One of the benefits of Bayesian methods is that well-founded estimates of uncertainty in models can be made available. So, for example, not only the mean time of a most recent common ancestor (tMRCA) is estimated, but also the spread. This distribution over model space is represented by a set of trees, which can be rather large and difficult to interpret. DensiTree is a tool that helps navigating these sets of trees. The main idea behind DensiTree is to draw all trees in the set transparently. As a result, areas where a lot of the trees agree in topology and branch lengths show up as highly colored areas, while areas with little agreement show up as webs. This makes it possible to quickly get an impression of properties of the tree set such as well-supported clades, distribution of tMRCA and areas of topological uncertainty. Thus, DensiTree provides a quick method for qualitative analysis of tree sets.}, doi = {10.1093/bioinformatics/btq110} } @ARTICLE{Bouckaert2014, author = {Remco R. Bouckaert and Joseph Heled}, title = {{DensiTree} 2: Seeing trees through the forest}, journal = {bioRxiv.org e-print service}, year = {2014}, volume = {bioRxiv:012401}, abstract = {Phylogenetic analysis like Bayesian MCMC or bootstrapping result in a collection of trees. Trees are discrete objects and it is generally difficult to get a mental grip on a distributions over trees. Visualisation tools like DensiTree can give good intuition on tree distributions. It works by drawing all trees in the set transparently thus highlighting areas where the tree in the set agrees. In this way, both uncertainty in clade heights and uncertainty in topology can be visualised. In our experience, a vanilla DensiTree can turn out to be misleading in that it shows too much uncertainty due to wrongly ordering taxa or due to unlucky placement of internal nodes. DensiTree is extended to allow visualisation of meta-data associated with branches such as population size and evolutionary rates. Furthermore, geographic locations of taxa can be shown on a map, making it easy to visually check there is some geographic pattern in a phylogeny. Taxa orderings have a large impact on the layout of the tree set, and advances have been made in finding better orderings resulting in significantly more informative visualisations. We also explored various methods for positioning internal nodes, which can improve the quality of the image. Together, these advances make it easier to comprehend distributions over trees.}, doi = {10.1101/012401} } @INPROCEEDINGS{Boutin2005, author = {Fran\c{c}ois Boutin and J\'er\^ome Thi\`evre and Mountaz Hasco\"et}, title = {Multilevel Compound Tree -- Construction Visualization and Interaction}, pages = {847--860}, abstract = {Several hierarchical clustering techniques have been proposed to visualize large graphs, but fewer solutions suggest a focus based approach. We propose a multilevel clustering technique that produces in linear time a contextual clustered view depending on a user-focus. We get a tree of clusters where each cluster - called meta-silhouette - is itself hierarchically clustered into an inclusion tree of silhouettes. Resulting Multilevel Silhouette Tree (MuSi-Tree) has a specific structure called multilevel compound tree. This work builds upon previous work on a compound tree structure called MO-Tree. The work presented in this paper is a major improvement over previous work by (1) defining multilevel compound tree as a more generic structure, (2) proposing original space-filling visualization techniques to display it, (3) defining relevant interaction model based on both focus changes and graph filtering techniques and (4) reporting from case studies in various fields: co-citation graphs, related-document graphs and social graphs.}, doi = {10.1007/11555261_67}, year = {2005}, booktitle = {INTERACT'05: Proceedings of the IFIP TC13 Conference on Human-Computer Interaction}, editor = {Maria Francesca Costabile and Fabio Patern\'o}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3540289437}, } @PATENT{Bowers1996, author = {Frank H. Bowers and Stuart K. Card}, title = {Method and apparatus for visualization of database search results}, number = {US 5546529}, year = {1996}, abstract = {A method and apparatus for representing the results of a search of a database. The present invention provides for creating a view of database search results via a tree structure in which detail is selected and context preserved. In the present invention, the tree structure is created based on user specified parameters. These parameters represent attributes of documents stored in the database and may differ from the search parameters. The tree structure is then mapped to a static reference surface which is visually perceived as three-dimensional. The reference surface is comprised of a detail area where detail of the tree structure is displayed and a context area for displaying other portions of the tree in less detail but which conveys to the viewer a sense of context. The tree structure may be scrolled about the reference surface to bring portions of the structure into a direct detail view while retaining a context view of the overall tree.}, url = {http://www.freepatentsonline.com/5546529.html} } @INPROCEEDINGS{Brath2012, author = {Richard Brath and Peter MacMurchy}, title = {Sphere-based Information Visualization: Challenges and Benefits}, pages = {1--6}, abstract = {Use of a sphere as a basis for organizing an information visualization should balance issues such as occlusion against potential useful benefits such as natural navigational affordances and perceptual connotations of an application.}, doi = {10.1109/IV.2012.11}, year = {2012}, booktitle = {IV'12: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Stefan Bertschi and Camilla Forsell and Jimmy Johansson and Sarah Kenderdine and Francis T. Marchese and Muhammad Sarfraz and Liz Stuart and Anna Ursyn and Theodor G. Wyeld and Hanane Azzag and Mustapha Lebba and Gilles Venturini}, publisher = {IEEE Computer Society}, isbn = {9780769547718} } @BOOK{Brinton1939, title = {Graphic Presentation}, publisher = {Brinton Associates}, year = {1939}, author = {Willard Cope Brinton}, abstract = {Graphic Presentation is largely a collection of interesting charts and pictures, mostly of a non-technical nature,covering a wide range of subject matter, with brief comment on methodology under each illustration. These charts and pictures are reproductions from numerous sources, including a few from his Graphic Methods. In addition to the chapters on types of charts and excerpts from Time Series Charts: A Manual of Design and Construction published by the American Society of Mechanical Engineers, there are some quasi-technical chapters on such things as the use of cameras and lantern slides, selection of paper, and methods of reproduction, printing, and binding. A chapter on tabulation is thrown in, apparently for good measure. Illustrations on alternate pairs of facing pages arc in color, and these pages contain also decorative chapter identification (bleed-outs) at the top and bottom. Printing was done by the photo offset process. The verbal language is Basic English. A minor feature of the book is a device whereby the reader may spin the pages rapidly until he reaches the desired chapter. On page 453 is given a detailed description of how the book was made up, including the names and addresses of the companies furnishing materials or services. This book departs from the earlier contribution in several respects. Text material is boiled down almost to the vanishing point, leaving the maximum number of charts to speak for themselves.}, url = {http://www.archive.org/details/graphicpresentat00brinrich} } @INPROCEEDINGS{Brodbeck2003, author = {Dominique Brodbeck and Luc Girardin}, title = {Visualization of Large-Scale Customer Satisfaction Surveys Using a Parallel Coordinate Tree}, pages = {197--201}, abstract = {Satisfaction surveys are an important measurement tool in fields such as market research or human resources management. Serious studies consist of numerous questions and contain answers from large population samples. Aggregation on both sides, the questions asked as well as the answers received, turns the multidimensional problem into a complex system of interleaved hierarchies. Traditional ways of presenting the results are limited to one-dimensional charts and cross-tables. We developed a visualization method called the Parallel Coordinate Tree that combines multidimensional analysis with a tree structure representation. Distortion-oriented focus+context techniques are used to facilitate interaction with the visualization. In this paper we present a design study of a commercial application that we built, using this method to analyze and communicate results from large-scale customer satisfaction surveys.}, doi = {10.1109/INFVIS.2003.1249026}, year = {2003}, booktitle = {InfoVis'03: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Tamara Munzner and Stephen North}, publisher = {IEEE Computer Society}, isbn = {0780381548} } @ARTICLE{BruggemannKlein1989, author = {Anne Br\"uggemann-Klein and Derick Wood}, title = {Drawing trees nicely with {\TeX}}, journal = {Electronic Publishing}, year = {1989}, volume = {2}, pages = {101--115}, number = {2}, abstract = {Various algorithms have been proposed for the difficult problem of producing aesthetically pleasing drawings of trees, see Reingold and Tilford (1981), Wetherell and Shannon (1979) but implementations only exist as ``special purpose software'', designed for special environments. Therefore, many users resort to the drawing facilites available on most personal computers, but the figures obtained in this way still look ``hand-drawn''; their quality is inferior to the quality of the surrounding text that can be realized by today''s high quality text processing systems. In this paper we present an entirely new solution that integrates a tree drawing algorithm into one of the best text processing systems available. More precisely, we present a TeX macro package TreeTeX that produces a drawing of a tree from a purely logical description. Our approach has three advantages. First, labels for nodes can be handled in a reasonable way. On the one hand, the tree drawing algorithm can compute the widths of the labels and take them into account for the positioning of the nodes; on the other hand, all the textual parts of the document can be treated uniformly. Second, TreeTeX can be trivially ported to any site running TeX. Finally, modularity in the description of a tree and TeX's macro capabilities allow for libraries of subtrees and tree classes. In addition, we have implemented an option that produces drawing which make the structure of the trees more obvious to the human eye, even though they may not be as aesthetically pleasing.}, url = {http://cajun.cs.nott.ac.uk/compsci/epo/papers/volume2/issue2/epabk022.pdf} } @INPROCEEDINGS{Bruls2000, author = {Mark Bruls and Kees Huizing and Jarke van Wijk}, title = {{Squarified Treemaps}}, pages = {33--42}, abstract = {An extension to the treemap method for the visualization of hierarchical information, such as directory structures and organization structures, is presented. The standard treemap method often gives thin, elongated rectangles. As a result, rectangles are difficult to compare and to select. A new method is presented to generate lay-outs in which the rectangles approximate squares. To strenghten the visualization of the structure, shaded frames are used around groups of related nodes.}, doi = {10.2312/VisSym/VisSym00/033-042}, year = {2000}, booktitle = {Data Visualization'00: Proceedings of the Joint Eurographics - IEEE TCVG Symposium on Visualization}, editor = {Wim de Leeuw and Robert van Liere}, publisher = {Eurographics Association}, isbn = {3211835156}, } @INPROCEEDINGS{Brunner2010, author = {Wolfgang Brunner and Marco Matzeder}, title = {Drawing ordered $(k-1)$-ary trees on $k$-grids}, pages = {105--116}, abstract = {We explore the complexity of drawing ordered $(k-1)$-ary trees on grids with k directions for $k\in\{4,6,8\}$ and within a given area. This includes, e.g., ternary trees drawn on the orthogonal grid. For aesthetically pleasing tree drawings on these grids, we additionally present various restrictions similar to the common hierarchical case. First, we generalize the NP-hardness of minimal width in hierarchical drawings of ordered trees to $(k-1)$-ary trees on k-grids and then we generalize the Reingold and Tilford algorithm to k-grids.}, doi = {10.1007/978-3-642-18469-7_10}, year = {2010}, booktitle = {GD'10: Proceedings of the International Symposium on Graph Drawing}, editor = {Ulrik Brandes and Sabine Cornelsen}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642184680}, } @INPROCEEDINGS{Buchheim2002, author = {Christoph Buchheim and Michael J\"unger and Sebastian Leipert}, title = {Improving {W}alker's Algorithm to Run in Linear Time}, pages = {347--364}, abstract = {The algorithm of Walker is widely used for drawing trees of unbounded degree, and it is widely assumed to run in linear time, as the author claims in his article. But the presented algorithm clearly needs quadraticrun time. We explain the reasons for that and present a revised algorithm that creates the same layouts in linear time.}, doi = {10.1007/3-540-36151-0_32}, year = {2002}, booktitle = {GD'02: Proceedings of the International Symposium on Graph Drawing}, editor = {Michael T. Goodrich and Stephen G. Kobourov}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540001584}, } @INPROCEEDINGS{Buchin2011, author = {Kevin Buchin and David Eppstein and Maarten L\"offler and Martin N\"ollenburg and Rodrigo I. Silveira}, title = {Adjacency-Preserving Spatial {Treemaps}}, year = {2011}, pages = {159--170}, abstract = {Rectangular layouts, subdivisions of an outer rectangle into smaller rectangles, have many applications in visualizing spatial information, for instance in rectangular cartograms in which the rectangles represent geographic or political regions. A spatial treemap is a rectangular layout with a hierarchical structure: the outer rectangle is subdivided into rectangles that are in turn subdivided into smaller rectangles. We describe algorithms for transforming a rectangular layout that does not have this hierarchical structure, together with a clustering of the rectangles of the layout, into a spatial treemap that respects the clustering and also respects to the extent possible the adjacencies of the input layout.}, doi = {10.1007/978-3-642-22300-6_14}, year = {2011}, booktitle = {WADS'11: Proceedings of the International Symposium on Algorithms and Data Structures}, editor = {Frank Dehne and John Iacono and J\"org-R\"udiger Sack}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642222993}, } @ARTICLE{Buchin2011a, author = {Kevin Buchin and David Eppstein and Maarten L\"offler and Martin N\"ollenburg and Rodrigo I. Silveira}, title = {Adjacency-Preserving Spatial {Treemaps}}, journal = {arXiv.org e-print service}, year = {2011}, volume = {1105.0398}, abstract = {Rectangular layouts, subdivisions of an outer rectangle into smaller rectangles, have many applications in visualizing spatial information, for instance in rectangular cartograms in which the rectangles represent geographic or political regions. A spatial treemap is a rectangular layout with a hierarchical structure: the outer rectangle is subdivided into rectangles that are in turn subdivided into smaller rectangles. We describe algorithms for transforming a rectangular layout that does not have this hierarchical structure, together with a clustering of the rectangles of the layout, into a spatial treemap that respects the clustering and also respects to the extent possible the adjacencies of the input layout.}, url = {http://arxiv.org/abs/1105.0398} } @INPROCEEDINGS{Buchin2011b, author = {Kevin Buchin and Bettina Speckmann and Kevin Verbeek}, title = {Angle-Restricted {Steiner} Arborescences for {Flow Map} Layout}, year = {2011}, pages = {35--38}, abstract = {Flow maps visualize the movement of objects between places. One or more sources are connected to several targets by arcs whose thickness corresponds to the amount of flow between a source and a target. Flow maps reduce visual clutter by merging (bundling) lines smoothly and by avoiding self-intersections. We present algorithms that compute crossing-free flows of high visual quality. To this end we introduce a new variant of the geometric Steiner arborescence problem. The goal is to connect the targets to a source with a tree of minimal length whose arcs obey a certain restriction on the angle they form with the source. Such an angle-restricted Steiner arborescence, or simply flow tree, naturally induces a clustering on the targets and smoothly bundles arcs. We study the properties of optimal flow trees and show that they consist of logarithmic spirals and straight lines. Computing optimal flow trees is NP-hard. Hence we consider a variant of flow trees which uses only logarithmic spirals, so called spiral trees. Spiral trees approximate flow trees within a factor depending on the angle restriction. Computing optimal spiral trees remains NP-hard. We present an efficient 2-approximation for spiral trees, which can be extended to avoid certain types of obstacles.}, url = {http://eurocg11.inf.ethz.ch/abstracts/25.pdf}, year = {2011}, booktitle = {EuroCG'11: Book of Abstracts of the European Workshop on Computational Geometry} } @ARTICLE{Buchin2011c, author = {Kevin Buchin and Bettina Speckmann and Kevin Verbeek}, title = {{Flow Map} Layout via {Spiral Trees}}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2011}, volume = {17}, pages = {2536--2544}, number = {12}, abstract = {Flow maps are thematic maps that visualize the movement of objects, such as people or goods, between geographic regions. One or more sources are connected to several targets by lines whose thickness corresponds to the amount of flow between a source and a target. Good flow maps reduce visual clutter by merging (bundling) lines smoothly and by avoiding self-intersections. Most flow maps are still drawn by hand and only few automated methods exist. Some of the known algorithms do not support edge-bundling and those that do, cannot guarantee crossing-free flows. We present a new algorithmic method that uses edge-bundling and computes crossing-free flows of high visual quality. Our method is based on so-called spiral trees, a novel type of Steiner tree which uses logarithmic spirals. Spiral trees naturally induce a clustering on the targets and smoothly bundle lines. Our flows can also avoid obstacles, such as map features, region outlines, or even the targets. We validate our approach with extensive experiments.}, doi = {10.1109/TVCG.2011.202} } @ARTICLE{Buchin2011d, author = {Kevin Buchin and Bettina Speckmann and Kevin Verbeek}, title = {Angle-Restricted {Steiner} Arborescences for {Flow Map} Layout}, journal = {arXiv.org e-print service}, year = {2011}, volume = {1109.3316}, abstract = {We introduce a new variant of the geometric Steiner arborescence problem, motivated by the layout of flow maps. Flow maps show the movement of objects between places. They reduce visual clutter by bundling lines smoothly and avoiding self-intersections. To capture these properties, our angle-restricted Steiner arborescences, or flux trees, connect several targets to a source with a tree of minimal length whose arcs obey a certain restriction on the angle they form with the source. We study the properties of optimal flux trees and show that they are planar and consist of logarithmic spirals and straight lines. Flux trees have the shallow-light property. We show that computing optimal flux trees is NP-hard. Hence we consider a variant of flux trees which uses only logarithmic spirals. Spiral trees approximate flux trees within a factor depending on the angle restriction. Computing optimal spiral trees remains NP-hard, but we present an efficient 2-approximation, which can be extended to avoid ``positive monotone'' obstacles.}, url = {http://arxiv.org/abs/1109.3316} } @INPROCEEDINGS{Budiu2006, author = {Raluca Budiu and Peter Pirolli and Michael Fleetwood}, title = {Navigation in degree of interest trees}, pages = {457--462}, abstract = {We present an experiment that compares how people perform search tasks in a degree-of-interest browser and in a Windows-Explorer-like browser. Our results show that, whereas users do attend to more information in the DOI browser, they do not complete the task faster than in an Explorer-like browser. However, in both types of browser, users are faster to complete high information scent search tasks than low information scent tasks. We present an ACT-R computational model of the search task in the DOI browser. The model describes how a visual search strategy may combine with semantic aspects of processing, as captured by information scent. We also describe a way of automatically estimating information scent in an ontological hierarchy by querying a large corpus (in our case, Google's corpus).}, doi = {10.1145/1133265.1133358}, year = {2006}, booktitle = {AVI'06: Proceedings of the Working Conference on Advanced Visual Interfaces}, editor = {Augusto Celentano and Piero Mussio}, publisher = {ACM Press}, isbn = {1595933530} } @INPROCEEDINGS{Budiu2007, author = {Raluca Budiu and Peter Pirolli}, title = {Modeling Navigation in {Degree-of-Interest Trees}}, pages = {845--850}, abstract = {We present an ACT-R (Anderson and Lebiere, 1998) computational model of how people navigate in a degree-of-interest (DOI) tree. The model incorporates a visual salience function that determines which part of the display to attend to next. The salience function uses visual features of the display (e.g., distances) and semantic features of labels (e.g., information scent). The model was compared against data from participants and provided medium to strong fits to latencies and the number of nodes visited by the participants. The model shows that it is useful to distinguish between category-based versus similarity-based information scent. It also suggests that visual distance and scent may interact with one another, with scent playing a greater role at distances close to the current node in the visual focus.}, url = {http://csjarchive.cogsci.rpi.edu/Proceedings/2007/docs/p845.pdf}, year = {2007}, booktitle = {CogSci'07: Proceedings of the Conference of the Cognitive Science Society}, editor = {Danielle S. McNamara and Greg Trafton}, publisher = {Psychology Press}, isbn = {9781605605074} } @INPROCEEDINGS{Burch2008, author = {Michael Burch and Fabian Beck and Stephan Diehl}, title = {{Timeline Trees}: visualizing sequences of transactions in information hierarchies}, pages = {75--82}, abstract = {In many applications transactions between the elements of an information hierarchy occur over time. For example, the product offers of a department store can be organized into product groups and subgroups to form an information hierarchy. A market basket consisting of the products bought by a customer forms a transaction. Market baskets of one or more customers can be ordered by time into a sequence of transactions. Each item in a transaction is associated with a measure, for example, the amount paid for a product. In this paper we present a novel method for visualizing sequences of these kinds of transactions in information hierarchies. It uses a tree layout to draw the hierarchy and a timeline to represent progression of transactions in the hierarchy. We have developed several interaction techniques that allow the users to explore the data. Smooth animations help them to track the transitions between views. The usefulness of the approach is illustrated by examples from several very different application domains.}, doi = {10.1145/1385569.1385584}, year = {2008}, booktitle = {AVI'08: Proceedings of the Working Conference on Advanced Visual Interfaces}, editor = {Paolo Bottoni and Stefano Levialdi}, publisher = {ACM Press}, isbn = {9781605581415} } @INPROCEEDINGS{Burch2010, author = {Michael Burch and Michael Raschke and Daniel Weiskopf}, title = {Indented Pixel Tree Plots}, pages = {338--349}, abstract = {We introduce Indented Pixel Tree Plots (IPTPs): a novel pixel-based visualization technique for depicting large hierarchies. It is inspired by the visual metaphor of indented outlines, omnipresent in graphical file browsers and pretty printing of source code. Inner vertices are represented as vertically arranged lines and leaf groups as horizontally arranged lines. A recursive layout algorithm places parent nodes to the left side of their underlying tree structure and leaves of each subtree grouped to the rightmost position. Edges are represented only implicitly by the vertically and horizontally aligned structure of the plot, leading to a sparse and redundant-free visual representation. We conducted a user study with 30 subjects in that we compared IPTPs and node-link diagrams as a within-subjects variable. The study indicates that working with IPTPs can be learned in less than 10 minutes. Moreover, IPTPs are as effective as node-link diagrams for accuracy and completion time for three typical tasks; participants generally preferred IPTPs. We demonstrate the usefulness of IPTPs by understanding hierarchical features of huge trees such as the NCBI taxonomy with more than 300,000 nodes.}, doi = {10.1007/978-3-642-17289-2_33}, year = {2010}, booktitle = {Advances in Visual Computing: Proceedings of the International Symposium on Visual Computing 2010}, editor = {George Bebis and Richard Boyle and Bahram Parvin and Darko Koracin and Ronald Chung and Riad Hammoud and Muhammad Hussain and Tan Kar-Han and Roger Crawfis and Daniel Thalmann and David kao and Lisa Avila}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3642172881}, } @INPROCEEDINGS{Burch2011, author = {Michael Burch and Daniel Weiskopf}, title = {Visualizing Dynamic Quantitative Data in Hierarchies. {TimeEdgeTrees}: Attaching Dynamic Weights to Tree Edges}, booktitle = {IVAPP'11: Proceedings of International Conference on Visualization Theory and Applications}, year = {2011}, pages = {177--186}, abstract = {In this paper we introduce a technique for visualizing the dynamics of quantitative data in static hierarchical structures. We exploit the straight links of orthogonal tree diagrams as a timeline on which we visually encode dynamic quantitative information. We use color coding and varying thicknesses to represent the time-varying data. Bimodal data can also be displayed by exploiting both sides of the time axes simultaneously. Our TimeEdgeTrees tool allows us to explore dynamic quantitative data in tree diagrams by interactive data filtering and zooming. The spatial proximity of neighboring hierarchically structured elements allows us to easily explore trends, countertrends, periodicity, temporal shifts, or anomalies during the evolution synchronously. Interactive features such as expanding or collapsing of subhierarchies additionally help to detect the aforementioned phenomena on different levels of granularity. The usefulness of our visualization technique is illustrated by water level data acquired at more than 450 measurement stations along German rivers for 768 points in time.}, url = {http://www.vis.uni-stuttgart.de/uploads/tx_vispublications/Burch2011.pdf} } @INPROCEEDINGS{Burch2011a, author = {Michael Burch and Hansj\"org Schmauder and Daniel Weiskopf}, title = {Indented Pixel Tree Browser for Exploring Huge Hierarchies}, pages = {301--312}, abstract = {In this paper we introduce the Indented Pixel Tree Browser -- an interactive tool for exploring, annotating, and comparing huge hierarchical structures on different levels of granularity. We exploit the indented visual metaphor to map tree structures to one-dimensional zigzag curves to primarily achieve an overview representation for the entire hierarchy. We focus on space-efficiency and simultaneous uncovering of tree-specific phenomena. Each displayed plot can be filtered for substructures that are mapped to a larger space and hence, unhide more fine-granular substructures that are hidden in the compressed overview. By representing tree structures side-by-side, the viewer can easily compare them visually and detect similar patterns and also anomalies. In our approach, we follow the information seeking mantra: overview first, zoom and filter, then details-on-demand. More interactive features such as expanding and collapsing of nodes, applying different color codings, or distorting the tree horizontally as well as vertically support a viewer when exploring huge hierarchical data sets. The usefulness of our interactive browsing tool is demonstrated in a case study for the NCBI taxonomy that contains 324,276 species and organisms that are hierarchically organized.}, doi = {10.1007/978-3-642-24028-7_28}, year = {2011}, booktitle = {Advances in Visual Computing: Proceedings of the International Symposium on Visual Computing 2011}, editor = {George Bebis and Richard Boyle and Bahram Parvin and Darko Koracin and Song Wang and Kim Kyungnam and Bedrich Benes and Kenneth Moreland and Christoph Borst and Stephen DiVerdi and Chiang Yi-Jen and Jiang Ming}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642240270}, } @INPROCEEDINGS{Burch2012, author = {Michael Burch and Michael Raschke and Miriam Greis and Daniel Weiskopf}, title = {Enriching Indented Pixel Tree Plots with Node-Oriented Quantitative, Categorical, Relational, and Time-Series Data}, pages = {102--116}, abstract = {Indented Pixel Tree Plots are useful for an overview of large and deep hierarchical data. As a major benefit, these plots scale to pixel or even subpixel resolution, still clearly visualizing the hierarchical structures and substructures in a redundant-free representation. Consequently, there is display space available that may be used to show additional information such as enlarged or filtered subregions, details-on-demand, or control panels. In this paper, we demonstrate how this compact indented diagram can be enriched with additional data associated with both leaf and inner nodes of the hierarchy. To this end, we support quantitative, categorical, relational, and time-series data. By such a combination, exploration and analysis of visual patterns and anomalies on different levels of hierarchical granularity are possible in a static diagram. Furthermore, interactive features such as expanding/collapsing of subhierarchies, horizontal/vertical distortions, zooming in/out, or details-on-demand are integrated to allow the user to inspect the data from different viewpoints. The usefulness of the enriched diagrams is illustrated by applying them to file system data where single software constructs are hierarchically organized. Here, we focus on quantitative, categorical, and relational data attached to the nodes of the hierarchy. In a second case study, we demonstrate how evolving water level data of rivers in Germany can be represented by our plots.}, doi = {10.1007/978-3-642-31223-6_14}, year = {2012}, booktitle = {Diagrammatic Representation and Inference: Proceedings of the International Conference Diagrams 2012}, editor = {Philip Cox and Beryl Plimmer and Peter Rodgers}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642312229}, } @PATENT{Cao2011, author = {Nan Cao and Shixia Liu and Hao Lu and Xi Jun Ma and Martin M. Wattenberg}, title = {Method and apparatus for improving the visibility of a {Treemap}}, number = {US 7870509 B2}, year = {2011}, abstract = {The visibility of a treemap is improved by offsetting the area of a parent node relative to a bounding box containing all of its child nodes while constructing the treemap, so that a part of the bounding box lies outside the area of the parent node, and the area of each child node in the bounding box is located entirely or partially within the area of the parent node. The present invention highlights the parent-child relationships in the treemap with a cascading effect to make the structural information therein more apparent and easier to recognize.}, url = {http://www.freepatentsonline.com/7870509.html} } @PATENT{Cao2013, author = {Nan Cao and Shi Xia Liu and Hui Su}, title = {Method and apparatus for generating {3D Carousel Tree} data visualization and related device}, number = {US 8621359 B2}, year = {2013}, abstract = {A method for generating 3D carousel visualization of large-scale tree data, which comprises the steps of: receiving a user's selection of a node in the carousel; according to the radius of a sub-carousel corresponding to the user-selected node and the radius of a carousel at which the selected node is located, judging whether or not the sub-carousel can be expanded at the carousel at which the selected node is located; expanding the sub-carousel at the carousel at which the selected node is located, if it is determined that the sub-carousel can be expanded at the carousel at which the selected node is located. A device capable of implementing the method is provided. The number of carousel levels visualized on a visualization device can be adjusted dynamically, and the visualization of a focus becomes more prominent, and relationships between nodes at each level of the tree data visualization get more apparent.}, url = {http://www.freepatentsonline.com/8621359.html} } @INPROCEEDINGS{Card2002, author = {Stuart K. Card and David Nation}, title = {Degree-of-interest trees: a component of an attention-reactive user interface}, pages = {231--245}, abstract = {This paper proposes Degree-of-Interest trees. These trees use degree-of-interest calculations and focus+context visualization methods, together with bounding constraints, to fit within pre-established bounds. The method is an instance of an emerging "attention-reactive" user interface whose components are designed to snap together in bounded spaces.}, doi = {10.1145/1556262.1556300}, year = {2002}, booktitle = {AVI'02: Proceedings of the Working Conference on Advanced Visual Interfaces}, publisher = {ACM Press}, isbn = {1581135378} } @PATENT{Card2005, author = {Stuart K. Card and David A. Nation}, title = {System and method for browsing hierarchically based node-link structures based on an estimated degree of interest}, number = {US 6944830 B2}, year = {2005}, abstract = {Method and system to enable a user to view large collections of hierarchically linked information on a computer based display. A tree structure visualization is created which presents a representation of the complete collection of information on the display. The visualization fits completely within a fixed area of the computer based display, negating the need to scroll information into the display area. The visualization is based on identified focus nodes and through calculation of a Degree of Interest (DOI) for each of the nodes based in the structure. Layout and presentation of the visualization structure is based on the DOI values in combination with considerations of available display space. A user may dynamically manipulate views of the structure by selecting one or more focus nodes, thus causing a recalculation of the degree of interest.}, url = {http://www.freepatentsonline.com/6944830.html} } @INPROCEEDINGS{Card2006, author = {Stuart K. Card and Bongwon Suh and Bryan A. Pendleton and Jeffrey Heer and John W. Bodnar}, title = {{TimeTree}: Exploring Time Changing Hierarchies}, pages = {3--10}, abstract = {Intelligence analysis often involves the task of gathering information about an organization. Knowledge about individuals in an organization and their relationships, often represented as a hierarchical organization chart, is crucial for understanding the organization. However, it is difficult for intelligence analysts to follow all individuals in an organization. Existing hierarchy visualizations have largely focused on the visualization of fixed structures and can not effectively depict the evolution of a hierarchy over time. We introduce TimeTree, a novel visualization tool designed to enable exploration of a changing hierarchy. TimeTree enables analysts to navigate the history of an organization, identify events associated with a specific entity (visualized on a TimeSlider), and explore an aggregate view of an individual's career path (a CareerTree). We demonstrate the utility of TimeTree by investigating a set of scenarios developed by an expert intelligence analyst. The scenarios are evaluated using a real dataset composed of eighteen thousand career events from more than eight thousand individuals. Insights gained from this analysis are presented.}, doi = {10.1109/VAST.2006.261450}, year = {2006}, booktitle = {VAST'06: Proceedings of the IEEE Symposium on Visual Analytics Science and Technology}, editor = {Pak Chung Wong and Daniel Keim}, publisher = {IEEE Computer Society}, isbn = {1424405912} } @INPROCEEDINGS{Carlson2006, author = {Josiah Carlson and David Eppstein}, title = {Trees with convex faces and optimal angles}, pages = {77--88}, abstract = {We consider drawings of trees in which all edges incident to leaves can be extended to infinite rays without crossing, partitioning the plane into infinite convex polygons. Among all such drawings we seek the one maximizing the angular resolution of the drawing. We find linear time algorithms for solving this problem, both for plane trees and for trees without a fixed embedding. In any such drawing, the edge lengths may be set independently of the angles, without crossing; we describe multiple strategies for setting these lengths.}, doi = {10.1007/978-3-540-70904-6_9}, year = {2006}, booktitle = {GD'06: Proceedings of the International Symposium on Graph Drawing}, editor = {Michael Kaufmann and Dorothea Wagner}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540709039}, } @INPROCEEDINGS{Carpendale2004, author = {Sheelagh Carpendale and Anand Agarawala}, title = {{PhylloTrees}: Harnessing Nature's Phyllotactic Patterns for Tree Layout}, pages = {7--8}, abstract = {We explore the use of nature’s phyllotactic patterns to inform the layout of hierarchical data. These naturally occurring patterns provide a non-overlapping, optimal packing when the total number of nodes is not known a priori. We present a family of expandable tree layouts based on these patterns.}, doi = {10.1109/INFVIS.2004.53}, year = {2004}, booktitle = {InfoVis'04: Poster Compendium of the IEEE Symposium on Information Visualization}, url = {http://conferences.computer.org/infovis/files/compendium2004.pdf} } @INPROCEEDINGS{Carriere1995, author = {Jeromy Carriere and Rick Kazman}, title = {Research report. Interacting with huge hierarchies: Beyond {Cone Trees}}, pages = {74--81}, abstract = {The paper describes an implementation of a tool for visualizing and interacting with huge information hierarchies, and some preliminary empirical evaluation of the tool's efficacy. Existing systems for visualizing huge hierarchies using cone trees "break down" once the hierarchy to be displayed exceeds roughly 1000 nodes, due to increasing visual clutter. The paper describes a system called fsviz which visualizes arbitrarily large hierarchies while retaining user control. This is accomplished by augmenting cone trees with several graphical and interaction techniques: usage-based filtering, animated zooming, hand-coupled rotation, fish-eye zooming, coalescing of distant nodes, texturing, effective use of colour for depth cueing, and the applications of dynamic queries. The fsviz system also improves upon earlier cone tree visualization systems through a more elaborate node layout algorithm. This algorithm enhances the usefulness of cone tree visualization for large hierarchies by all but eliminating clutter.}, doi = {10.1109/INFVIS.1995.528689}, year = {1995}, booktitle = {InfoVis'95: Proceedings of the IEEE Symposium On Information Visualization}, editor = {Nahum D. Gershon and Stephen G. Eick}, publisher = {IEEE Computer Society}, isbn = {0818672013} } @INPROCEEDINGS{Cava2002, author = {Ricardo A. Cava and Paulo R. G. Luzzardi and Carla M. D. S. Freitas}, title = {The Bifocal Tree: A Technique for the Visualization of Hierarchical Information Structures}, booktitle = {IHC'02: Proceedings of the Workshop on Human factors in Computer Systems}, year = {2002}, abstract = {This paper reports a new technique for visualizing hierarchies which is based on the focus+context concept, but uses two foci instead of one. The technique allows improving the presentation of details related to some item in the information space as well as the context. This is achieved by displaying the hierarchy as a node-edge diagram separated in two connected sub-diagrams. One corresponds to the subtree with the node of interest as root. The other one represents the context and contains the selected node parent and remaining subtrees. Interaction issues regarding browsing and other operations are also discussed.}, url = {http://www.irit.fr/~Marco.Winckler/projects/spider/publications/IHC2002-CavaEtAl.pdf} } @ARTICLE{Cesarano2016, author = {Antonio Cesarano and Filomena Ferrucci and Mario Torre}, title = {A heuristic extending the Squarified treemapping algorithm}, journal = {arXiv.org e-print service}, year = {2016}, volume = {1609.00754}, abstract = {A heuristic extending the Squarified Treemap technique for the representation of hierarchical information as treemaps is presented. The original technique gives high quality treemap views, since items are laid out with rectangles that approximate squares, allowing easy comparison and selection operations. New key steps, with a low computational impact, have been introduced to yield treemaps with even better aspect ratios and higher homogeneity among items.}, url = {http://arxiv.org/abs/1609.00754} } @INPROCEEDINGS{Chaudhuri2009, author = {Abon Chaudhuri and Han-Wei Shen}, title = {A Self-adaptive Treemap-based Technique for Visualizing Hierarchical Data in {3D}}, pages = {105--112}, abstract = {In this paper, we present a novel adaptive visualization technique where the constituting polygons dynamically change their geometry and other visual attributes depending on user interaction. These changes take place with the objective of conveying required level of detail to the user through each view. Our proposed technique is successfully applied to build a treemap-based but 3D visualization of hierarchical data, a widely used information structure. This new visualization exploits its adaptive nature to address issues like cluttered display, imperceptible hierarchy, lack of smooth zoom-in and out technique which are common in tree visualization. We also present an algorithm which utilizes the flexibility of our proposed technique to deal with occlusion, a problem inherent in any 3D information visualization. On one hand, our work establishes adaptive visualization as a means of displaying tree-structured data in 3D. On the other, it promotes the technique as a potential candidate for being employed to visualize other information structures also.}, doi = {10.1109/PACIFICVIS.2009.4906844}, year = {2009}, booktitle = {PacificVis'09: Proceedings of the IEEE Pacific Visualization Symposium}, editor = {Peter Eades and Thomas Ertl and Han-Wei Shen}, publisher = {IEEE Computer Society}, isbn = {9781424444055} } @MASTERSTHESIS{Chauhan2010, author = {Janki Chauhan}, title = {Analysis and extension of tree visualization}, school = {University of Texas, Dallas}, year = {2010}, abstract = {Information visualization has always attracted human eye, as visual representation and interaction techniques allows one's mind to explore and understand large amount of information at a glance. Various information visualization techniques have been developed to show results in novel forms like graph drawing, hyperbolic tree, tree mapping and many more. Some recent development in visualization techniques has been done using fractal grammar and adoption for some existing aesthetic forms. This thesis presents how the existing algorithm of tree-mapping can be made more interactive and informative for end users. By adding level based information display, displaying communities in tree and treemap and animating the tree drawing adds more readability and reduces ambiguity of treemap. We will also discuss, what are various ways for data to be extracted and how new information can be derived from a given data set.}, url = {http://search.proquest.com/docview/851128424/abstract} } @ARTICLE{Chen2010, author = {Xiaowu Chen and Haolin Yang and Yongtao Ma and Bin Zhou}, title = {A Magic Treemap Cube for Visualizing Olympic Games Data}, journal = {The International Journal of Virtual Reality}, year = {2010}, volume = {9}, pages = {9--17}, number = {3}, abstract = {Treemap, a common information visualization approach for dividing a display area into nested rectangles, has a good performance on visualizing hierarchical data. And it enables user to compare nodes in the same level and to learn certain relationship between adjacent levels. However, treemap layout is limited to visualize multi-dimensional hierarchical data in which the hierarchy is unfixed and complex, especially when the hierarchy is an arbitrary graph. Considering this problem, we present a novel extension called magic treemap cube, which improves the layout and has a good performance on visualizing unfixed (cross-level) and complex data, inverting hierarchy without reorganizing the structure, and enabling users to easily compare among treemaps. The magic treemap cube is a three-dimensional regular hexahedron whose six faces are covered by six different treemaps. Each dimension of the magic treemap cube is a hierarchy structure specified by users according to a hierarchical division of visualization information. With the treemap algorithm, tagcloud and mapping rules, the treemaps are automatically controlled by permutations of three dimensions of the cube. Users could observe the six correlative treemaps respectively by rotating the magic treemap cube in three dimensional Cartesian coordinate. And this magic treemap cube can be unfolded into a tiled treemap in 2D Cartesian coordinate for users-friendly comparison of each treemap. Meanwhile, a merging operation to the tiled treemap is proposed to not only compare two treemaps through the adjacency relations among faces but also provide more information. For demonstrating the above characteristics, an application (called OlympicVis) has been implemented to visualize the Beijing 2008 Olympic Games information, which involves multi-dimensional hierarchy and interconnected data. The OlympicVis can display Cube View, Schedule View, Medal View, Date Filter and Time Line.}, url = {http://www.ijvr.org/issues/issue3-2010/paper2.pdf} } @ARTICLE{Chen2015, author = {Yi Chen and Xinyue Zhang and Yuchao Feng and Jie Liang and Hongqian Chen}, title = {Sunburst with ordered nodes based on hierarchical clustering: A visual analyzing method for associated hierarchical pesticide residue data}, journal = {Journal of Visualization}, year = {2015}, volume = {18}, pages = {237--254}, number = {2}, abstract = {According to the characteristics of pesticide residue data and analyzing requirements in food safety fields, we presented a visual analyzing method for associated hierarchical data, called sunburst with ordered nodes based on hierarchical clustering (SONHC). SONHC arranged the leaf nodes in sunburst in order using hierarchical clustering algorithm, put the associated dataset as a node in center of the sunburst, and connected it with the associated leaf nodes in sunburst using colored lines. So, it can present not only two hierarchical structures but also the relationships between them. Based on SONHC and some interaction techniques (clicking, contraction and expansion, etc) we developed an associated visual analyzing system (AVAS) for pesticide residues detection results data, which can help users to inspect the hierarchical structure of pesticide and agricultural products and to explore the associations between pesticides and agricultural products, and associations between different pesticides. The results of user experience test showed that SONHC algorithm overperforms than SA and SR algorithm in ULE and ULE’s variance. AVAS system is effective in helping users to analyze the pesticide residues data. Furthermore, SONHC algorithm can also be adopted to analyze associated hierarchical data in other fields, such as finance, insurance and e-commerce.}, doi = {10.1007/s12650-014-0269-3} } @INPROCEEDINGS{Chevalier2007, author = {Fanny Chevalier and David Auber and Alexandru Telea}, title = {Structural Analysis and Visualization of {C}++ Code Evolution using Syntax Trees}, pages = {90--97}, abstract = {We present a method to detect and visualize evolution patterns in C++ source code. Our method consists of three steps. First, we extract an annotated syntax tree (AST) from each version of a given C++ source code. Next, we hash the extracted syntax nodes based on a metric combining structure and type information, and construct matches (correspondences) between similar-hash subtrees. Our technique detects code fragments which have not changed, or changed little, during the software evolution. By parameterizing the similarity metric, we can flexibly decide what is considered to be identical or not during the software evolution. Finally, we visualize the evolution of the code structure by emphasizing both changing and constant code patterns. We demonstrate our technique on a versioned code base containing a variety of changes ranging from simple to complex.}, doi = {10.1145/1294948.1294971}, year = {2007}, booktitle = {IWPSE'07: Proceedings of the International workshop on Principles of Software Evolution}, editor = {Massimiliano Di Penta and Michele Lanza}, publisher = {ACM Press}, isbn = {9781595937223} } @INPROCEEDINGS{Chhetri2012, author = {Abhishek P. Chhetri and Kang Zhang}, title = {Modified {RELT} for Display and Navigation of Large Hierarchy on Handheld Touch-Screen Devices}, pages = {147--152}, abstract = {Visualizing and exploring a hierarchical structure on a smartphone screen is challenging. On larger screens of PCs and laptops these types of structures are often shown in a tabular view. Due to the width restriction, tabular view is not feasible on smaller screens. This paper presents a visualization technique that displays multiple levels of a hierarchical structure on a single view for small screens and allows users to explore the structure rapidly through touch input. The visualization technique makes full use of the available space and distributes the space fairly among nodes. The system allows selection and display of relevant information based on user query or user habit, while hiding less important items from the view.}, doi = {10.1109/ICIS.2012.73}, year = {2012}, booktitle = {ICIS'12: Proceedings of the IEEE/ACIS International Conference on Computer and Information Science}, publisher = {IEEE Computer Society}, isbn = {9780769546940} } @INPROCEEDINGS{Chhetri2013, author = {Abhishek P. Chhetri and Kang Zhang and Eakta Jain}, title = {{ERELT}: a faster alternative to the list-based interfaces for tree exploration and searching in mobile devices}, pages = {54--63}, abstract = {This paper presents ERELT (Enhanced Radial Edgeless Tree), a tree visualization approach on modern mobile devices. ERELT is designed to offer a clear visualization of any tree structure with intuitive interaction. We are interested in both the observation and navigation of such structures. Such visualization can assist users in interacting with a hierarchical structure such as a media collection, file system, etc. In the ERELT visualization, a subset of the tree is displayed at a time. The displayed tree size depends on the maximum number of tree elements that can be put on the screen while maintaining clarity. Users can quickly navigate to the hidden parts of the tree through touch-based gestures. We conducted a user study to evaluate this visualization for a music collection. Test results show that this approach reduces the time and effort in navigating tree structures for exploration and search tasks.}, doi = {10.1145/2493102.2493109}, year = {2013}, booktitle = {VINCI'13: Proceedings of the International Symposium on Visual Information Communication and Interaction}, publisher = {ACM Press}, isbn = {9781450319881} } @ARTICLE{Chhetri2015, author = {Abhishek P. Chhetri and Kang Zhang and Eakta Jain}, title = {A mobile interface for navigating hierarchical information space}, journal = {Journal of Visual Languages and Computing}, year = {2015}, volume = {31}, pages = {48--69}, number = {Part A}, abstract = {This paper presents ERELT (Enhanced Radial Edgeless Tree), a tree visualization approach on modern mobile devices. ERELT is designed to offer a clear visualization of any tree structure with intuitive interaction. Such visualization can assist users in interacting with a hierarchical structure such as a media collection, file system, etc. In the ERELT visualization, a subset of the tree is displayed at a time. The displayed tree size depends on the maximum number of tree elements that can be put on the screen while maintaining clarity. Users can quickly navigate to the hidden parts of the tree through touch-based gestures. We have conducted a user study to evaluate this visualization for a music collection. The study results show that this approach reduces the time and effort in navigating tree structures for exploration and search tasks.}, doi = {10.1016/j.jvlc.2015.10.002} } @INPROCEEDINGS{Chintalapani2004, author = {Gouthami Chintalapani and Catherine Plaisant and Ben Shneiderman}, title = {Extending the utility of treemaps with flexible hierarchy}, pages = {335--344}, abstract = {Treemaps are a visualization technique for presenting hierarchical information on two-dimensional displays. Prior implementations limit the visualization to pre-defined static hierarchies. Flexible hierarchy, a new capability of Treemap 4.0, enables users to define various hierarchies through dynamically selecting a series of data attributes so that they can discover patterns, clusters and outliers. This work describes the design and implementation issues of flexible hierarchy. It then reports on a usability study, which led to enhancements to the interface.}, doi = {10.1109/IV.2004.1320166}, year = {2004}, booktitle = {IV'04: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Katy B\"orner and Chaomei Chen and Muhammad Dastbaz and Gordon Clapworthy and Anthony Faiola and Ebroul Izquierdo and Carsten Maple and Jonathan Roberts and Chris Moore and Anna Ursyn and Jian J. Zhang}, publisher = {IEEE Computer Society}, isbn = {0769521770} } @INPROCEEDINGS{Choi2011, author = {Junghong Choi and Oh-hyun Kwon and Kyungwon Lee}, title = {Strata Treemaps}, pages = {87}, abstract = {Treemap is a method of visualization to recognize a hierarchical structure of data using the size and arrangement of nested rectangles. A limitation of a treemap is the difficulty to discern the structure of a hierarchy. Several approaches have been proposed to improve the visibility of the hierarchical structure. These approaches involve the use of a border or padding to emphasize the hierarchical structure. However, this leads to a disparity between the node weight and the relative node size.}, doi = {10.1145/2037715.2037813}, year = {2011}, booktitle = {SIGGRAPH'11: Posters of the Special Interest Group on Computer Graphics and Interactive Techniques Conference} } @INPROCEEDINGS{Chuah1998, author = {Mei C. Chuah}, title = {Dynamic Aggregation with Circular Visual Designs}, pages = {35--43}, abstract = {One very effective method for managing large data sets is aggregation or binning. We consider two aggregation methods that are tightly coupled with interactive manipulation and the visual representation of the data. Through this integration we hope to provide effective support for the aggregation process, specifically by enabling: 1) automatic aggregation, 2) continuous change and control of the aggregation level, 3) spatially based aggregates, 4) context maintenance across different aggregate levels, and 5) feedback on the level of aggregation.}, doi = {10.1109/INFVIS.1998.729557}, year = {1998}, booktitle = {InfoVis'98: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Graham Wills and John Dill}, publisher = {IEEE Computer Society}, isbn = {0818690933} } @INPROCEEDINGS{Chuanxi2011, author = {Chen Chuanxi and Qi Mian}, title = {Visualization of Syntax Tree Based on {VML}}, pages = {538--541}, abstract = {In the Chinese teaching and research, it often needs to draw syntax tree for the analyzing of relationship among compositions of sentence. Drawn syntax tree manually has many defects, such as having huge workload, needing immense storage capacity and so on. So it is of importance to do research of automatically generating syntax tree and its visualization. In this paper, it proposes a method to generate syntax tree automatically and display the syntax tree in web page by using VML technology. By comparing the syntax trees generated in this paper with the syntax trees got from Treebank of PKU, the result shows that the method of coordinate computing proposed in this paper is more precision, which also demonstrates the efficiency of the visualization method.}, doi = {10.1109/ISIE.2011.68}, year = {2011}, booktitle = {ISIE'11: Proceedings of the International Conference on Intelligence Science and Information Engineering}, publisher = {IEEE Computer Society}, isbn = {9780769544809} } @INPROCEEDINGS{Churcher1999, author = {Neville Churcher and Lachlan Keown and Warwick Irwin}, title = {Virtual Worlds for Software Visualisation}, pages = {9--16}, abstract = {Understanding, quickly, completely and correctly, is crucial to every phase of the software development process. As system size and complexity continues to grow, effective visualisation of system components, together with their properties and relationships, becomes increasingly important in achieving understanding. Virtual worlds allow more information to be presented in visualisations while minimising the impact of cognitive information overload. In this paper, we describe our application of virtual worlds to visualisation of software engineering artifacts and present some examples from our work on object oriented software systems.}, url = {http://www.cosc.canterbury.ac.nz/research/RG/svg/softvis99/softvis99-churcher-keown-irwin.pdf}, year = {1999}, booktitle = {SoftVis'99: Proceedings of the Software Visualisation Workshop} } @INPROCEEDINGS{Cleary2004, author = {Brendan Cleary and Chris Exton}, title = {{CHIVE} -- A program source visualisation framework}, pages = {268--269}, abstract = {The CHIVE visualisation framework is an attempt to provide program comprehension and visualisation tool developers with a flexible means for creating 3-dimensional visualisations of hierarchies such as those that occur in program source. The CHIVE framework supports user definable datasets, multiple graph layouts and an environment in which users can interact with visualisations created from applying a graph layout to a dataset.}, doi = {10.1109/WPC.2004.1311074}, year = {2004}, booktitle = {WPC'04: Proceedings of the IEEE Workshop on Program Comprehension}, publisher = {IEEE Computer Society}, isbn = {0769521495} } @PATENT{CliftonBligh2004, author = {Gervase Clifton-Bligh}, title = {Methods and devices for mapping data files}, number = {US 6775659 B2}, year = {2004}, abstract = {A method of mapping interconnections between a plurality of data files, such as files of the world wide web. The method comprises a step of, for a first file, in a display area displaying a first region. Then, according to a first distance scale, displaying one or more second regions, which respectively represent one or more second files logically related to the first file, for example by hyperlinks. The second regions are spatially related in a display to the first region. In (n-1) further steps, i=2,... , n, the method displays according to an i-th distance scale smaller than the (i-1)-th distance scale one or more (i+1)-th regions. Each of these (i+1)-th regions respectively represent one or more (i+1)-th files which are logically related to the i-th file, and they are spatially related on a display to the i-th region representing that i-th file. The method may be implemented in software, for example in a web browser.}, url = {http://www.freepatentsonline.com/6775659.html} } @PATENT{CliftonBligh2010, author = {Gervase Clifton-Bligh}, title = {Methods and devices for selecting items such as data files}, number = {US 7764272 B1}, year = {2010}, abstract = {A method is described for allowing a user to select one of a plurality of items. The user employs a device having a display area, and a joystick or a contact sensitive area. The device displays a number of regions equal to the number of items, and defines a number of sections in the angular range of the joystick, or sections within the contact sensitive area, equal to the number of items, and arranged corresponding to the arrangement of the regions of the display area. The user selects one of said items by selecting the corresponding section.}, url = {http://www.freepatentsonline.com/7764272.html} } @INPROCEEDINGS{Cockburn2000, author = {Andy Cockburn and Bruce McKenzie}, title = {An Evaluation of {Cone Trees}}, pages = {425--436}, abstract = {Cone Trees are an appealing interactive 3D visualization technique for hierarchical data structures. They were originally intended to maximise effective use of available screen space and to better exploit the abilities of the human perceptual system. Prior work has focused on the fidelity of the visualization rather than providing empirical user studies. This paper describes the design, implementation and evaluation of a low-fidelity animated and rapidly interactive 3D cone tree system. Results of the evaluation show that our subjects were slower at locating data using cone trees than when using a 'normal' tree browser, and that their performance deteriorated rapidly as the branching factor of the data-structure increased. Qualitative results, however, indicate that the subjects were enthusiastic about the cone tree visualization and that they felt it provided a better 'feel' for the structure of the information space.}, url = {http://hdl.handle.net/10092/522}, year = {2000}, booktitle = {People and Computers XIV -- Usability or Else! Proceedings of the Human Computer Interaction 2000}, editor = {Sharon McDonald and Yvonne Waern and Gilbert Cockton}, publisher = {Springer}, isbn = {9781852333188} } @ARTICLE{Collins2009, author = {Christopher Collins and Sheelagh Carpendale and Gerald Penn}, title = {{DocuBurst}: Visualizing Document Content using Language Structure}, journal = {Computer Graphics Forum}, year = {2009}, volume = {28}, pages = {1039-1046}, number = {3}, abstract = {Textual data is at the forefront of information management problems today. One response has been the development of visualizations of text data. These visualizations, commonly based on simple attributes such as relative word frequency, have become increasingly popular tools. We extend this direction, presenting the first visualization of document content which combines word frequency with the human-created structure in lexical databases to create a visualization that also reflects semantic content. DocuBurst is a radial, space-filling layout of hyponymy (the IS-A relation), overlaid with occurrence counts of words in a document of interest to provide visual summaries at varying levels of granularity. Interactive document analysis is supported with geometric and semantic zoom, selectable focus on individual words, and linked access to source text.}, doi = {10.1111/j.1467-8659.2009.01439.x} } @ARTICLE{Crescenzi1992, author = {Pierluigi Crescenzi and Giuseppe Di Battista and Adolfo Piperno}, title = {A note on optimal area algorithms for upward drawings of binary trees}, journal = {Computational Geometry}, year = {1992}, volume = {2}, pages = {187--200}, number = {4}, abstract = {The goal of this paper is to investigate the area requirements for upward grid drawings of binary trees. First, we show that there is a family of binary trees with n vertices that require w(n*logn) area; this bound is tight to within a constant factor, i.e. any binary tree with n vertices can be drawn in O(n*logn) area. Then we present an algorithm for constructing an upward drawing of a complete binary tree with n vertices in O(n) area, and, finally, we extend this result to the drawings of Fibonacci trees.}, doi = {10.1016/0925-7721(92)90021-J} } @INPROCEEDINGS{Crescenzi1997, author = {Pilu Crescenzi and Paolo Penna}, title = {Minimum-area h-v drawings of complete binary trees}, pages = {371--382}, abstract = {We study the area requirement of h-v drawings of complete binary trees. An h-v drawing of a binary tree t is a drawing of t such that (a) nodes are points with integer coordinates, (b) each edge is either a rightward-horizontal or a downward-vertical straight-line segment from a node to one of its children, (c) edges do not intersect, and (d) if t 1 and t 2 are immediate subtrees of a node u, the enclosing rectangles of the drawings of t 1 and t 2 are disjoint. We prove that, for any complete binary tree t of height h SQRT((n+1)/2)+3.5 if h is odd, (b) 2.5n–3.25SQRT(n+1)+3.5 otherwise. As far as we know, this is one of the few examples in which a closed formula for the minimum-area drawing of a graph has been explicitly found. Furthermore this minimum-area h-v drawing can be constructed in linear time. As a consequence of this result and the result of Trevisan (1996), we have that h-v drawings are provably less area-efficient than strictly upward drawings when we restrict ourselves to complete binary trees. We also give analogous results for the minimum-perimeter and the minimum-enclosing square area h-v drawings.}, doi = {10.1007/3-540-63938-1_82}, year = {1997}, booktitle = {GD'97: Proceedings of the International Symposium on Graph Drawing}, editor = {Giuseppe DiBattista}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3540639381}, } @INPROCEEDINGS{Csallner2003, author = {Christoph Csallner and Marcus Handte and Othmar Lehmann and John Stasko}, title = {{FundExplorer}: Supporting the diversification of mutual fund portfolios using {C}ontext {T}reemaps}, pages = {203--208}, abstract = {An equity mutual fund is a financial instrument that invests in a set of stocks. Any two different funds may partially invest in some of the same stocks, thus overlap is common. Portfolio diversification aims at spreading an investment over many different stocks in search of greater returns. Helping people with portfolio diversification is challenging because it requires informing them about both their current portfolio of stocks held through funds and the other stocks in the market not invested in yet. Current stock/fund visualization systems either waste screen real estate and visualization of all data points. We have developed a system called FundExplorer that implements a distorted treemap to visualize both the amount of money invested in a person's fund portfolio and the context of remaining market stocks. The FundExplorer system enables people to interactively explore diversification possibilities with their portfolios.}, doi = {10.1109/INFVIS.2003.1249027}, year = {2003}, booktitle = {InfoVis'03: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Tamara Munzner and Stephen North}, publisher = {IEEE Computer Society}, isbn = {0780381548} } @INPROCEEDINGS{Cuadros2007, author = {Ana M. Cuadros and Fernando V. Paulovich and Rosane Minghim and Guilherme P. Telles}, title = {Point Placement by Phylogenetic Trees and its Application to Visual Analysis of Document Collections}, pages = {99--106}, abstract = {The task of building effective representations to visualize and explore collections with moderate to large number of documents is hard. It depends on the evaluation of some distance measure among texts and also on the representation of such relationships in bi- dimensional spaces. In this paper we introduce an alternative approach for building visual maps of documents based on their content similarity, through reconstruction of phylogenetic trees. The tree is capable of representing relationships that allows the user to quickly recover information detected by the similarity metric. For a variety of text collections of different natures we show that we can achieve improved exploration capability and more clear visualization of relationships amongst documents.}, doi = {10.1109/VAST.2007.4389002}, year = {2007}, booktitle = {VAST'07: Proceedings of the IEEE Symposium on Visual Analytics Science and Technology}, editor = {William Ribarsky and John Dill}, publisher = {IEEE Computer Society}, isbn = {9781424416592} } @INPROCEEDINGS{Culy2010, author = {Chris Culy and Verena Lyding}, title = {{Double Tree}: An Advanced {KWIC} Visualization for Expert Users}, pages = {98--103}, abstract = {In this paper we present Double Tree, a new visualization of Key Word In Context (KWIC) displays targeted to support linguistic analysis. Inspired by Wattenberg's and Viegas' Word Tree visualization, Double Tree extends the idea of representing KWIC results as trees. We address several issues with Word Trees with respect to the specific demands of linguists and discuss the design decisions and implementation details that we chose for Double Tree. In particular we present our approach for displaying a two-sided tree. We describe details of the layout, including how frequency and linguistic information is incorporated, and what user interaction is supported. We conclude with some consideration on possible next steps for Double Tree.}, doi = {10.1109/IV.2010.24}, year = {2010}, booktitle = {IV'10: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Stefan Bertschi and Remo Burkhard and John Counsell and Mohammad Dastbaz and Martin Eppler and Camilla Forsell and Georges Grinstein and Jimmy Johansson and Mikael Jern and Farzad Khosrowshahi and Francis T. Marchese and Carsten Maple and Richard Laing and Urska Cvek and Marjan Trutschl and Muhammad Sarfraz and Liz Stuart and Anna Ursyn and Theodor G. Wyeld}, publisher = {IEEE Computer Society}, isbn = {9780769541655} } @INPROCEEDINGS{Dachselt2001, author = {Raimund Dachselt and J\"urgen Ebert}, title = {Collapsible Cylindrical Trees: A Fast Hierarchical Navigation Technique}, pages = {79-86}, abstract = {This paper proposes a new visualization and interaction technique for medium-sized trees, called Collapsible Cylindrical Trees (CCT). Child nodes are mapped on rotating cylinders, which will be dynamically displayed or hidden to achieve a useful balance of detail and context. Besides a comprehensible three-dimensional visualization of trees, the main feature of CCT is a very fast and intuitive interaction with the displayed nodes. Only a single click is needed to reach every node and perform an action on it, such as displaying a web page. The CCT browsing technique was developed for interaction with web hierarchies but is not limited to this domain. We also present sample implementations of CCT using VRML, which show the usefulness of this intuitive tree navigation technique.}, doi = {10.1109/INFVIS.2001.963284}, year = {2001}, booktitle = {InfoVis'01: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Keith Andrews and Steven Roth and Pak Chung Wong}, publisher = {IEEE Computer Society}, isbn = {0769513425} } @INPROCEEDINGS{Dang2017, author = {Tommy Dang and Angus Forbes}, title = {{CactusTree}: A tree drawing approach for hierarchical edge bundling}, pages = {210--214}, abstract = {This paper introduces CactusTree, a novel visualization technique for representing hierarchical datasets. We introduce details about the construction of CactusTrees and describe how they can be used to represent nested data and relationships between elements in the data. We explain how our design decisions were informed by tasks common to a range of scientific domains. A key contribution of this article is the introduction of descriptive features that can be used to characterize trees in terms of their structural and connective qualities.}, doi = {10.1109/PACIFICVIS.2017.8031596}, year = {2017}, booktitle = {PacificVis'17: Proceedings of the IEEE Pacific Visualization Symposium}, editor = {Daniel Weiskopf and Yingcai Wu and Tim Dwyer}, publisher = {IEEE Computer Society}, isbn = {9781509057382} } @INPROCEEDINGS{Dang2017a, author = {Tommy Dang and Paul Murray and Ronak Etemadpour and Angus G. Forbes}, title = {A User Study of Techniques for Visualizing Structure and Connectivity in Hierarchical Datasets}, pages = {45--59}, abstract = {Many tree layouts have been created for presenting hierarchical data. However, layouts optimized for some tasks are not adequate for others. In this paper, we focus on identifying tree structures and cross-links generated by hierarchical edge bundling. Our key contribution is the introduction of descriptive features that can be used to characterize trees in terms of their structural and connective qualities. We present a user study with 14 subjects that provides an evaluation of our approach in comparison to other popular tree visualization techniques. The results of the study indicate which techniques are more effective for visual analysis tasks that involve identifying and comparing tree and subtree structures and/or visualizing connections using hierarchical edge bundling.}, url = {http://ceur-ws.org/Vol-1947/paper05.pdf}, year = {2017}, booktitle = {VOILA'17: Proceedings of the International Workshop on Visualization and Interaction for Ontologies and Linked Data}, editor = {Valentina Ivanova and Patrick Lambrix and Steffen Lohmann and Catia Pesquita}, publisher = {CEUR-WS} } @INPROCEEDINGS{Demaine2011, author = {Erik D. Demaine and Andr\'e Schulz}, title = {Embedding Stacked Polytopes on a Polynomial-Size Grid}, pages = {1177--1187}, abstract = {We show how to realize a stacked 3D polytope (formed by repeatedly stacking a tetrahedron onto a triangular face) by a strictly convex embedding with its n vertices on an integer grid of size $O(n^4)\times O(n^4)\times O(n^{18})$. We use a perturbation technique to construct an integral 2D embedding that lifts to a small 3D polytope, all in linear time. This result solves a question posed by G\"unter M. Ziegler, and is the first nontrivial subexponential upper bound on the long-standing open question of the grid size necessary to embed arbitrary convex polyhedra, that is, about efficient versions of Steinitz's 1916 theorem. An immediate consequence of our result is that $O(\log n)$-bit coordinates suffice for a greedy routing strategy in planar 3-trees.}, url = {http://www.siam.org/proceedings/soda/2011/SODA11_088_demainee.pdf}, year = {2011}, booktitle = {SODA'11: Proceedings of the ACM-SIAM Symposium on Discrete Algorithms}, editor = {Dana Randall}, publisher = {Society for Industrial and Applied Mathematics} } @INPROCEEDINGS{Demetrescu1999, author = {Camil Demetrescu and Giuseppe Di Battista and Irene Finocchi and Giuseppe Liotta and Maurizio Patrignani and Maurizio Pizzonia}, title = {Infinite trees and the future}, pages = {379--391}, abstract = {We study the problem of designing layout facilities for the navigation of an "infinite" graph, i.e. a graph that is so large that its visualization is unfeasible, even by gluing together all the screen snapshots that a user can take during the navigation. We propose a framework for designing layout facilities that support the navigation of an infinite tree. The framework allows to exploit the knowledge of future moves of the user in order to reduce the changes in her mental map during the navigation. Variants of the classical Reingold-Tilford algorithm are presented and their performance is studied both experimentally and analytically.}, doi = {10.1007/3-540-46648-7_39}, year = {1999}, booktitle = {GD'99: Proceedings of the International Symposium on Graph Drawing}, editor = {Jan Kratochv\'{\i}yl}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3540669043}, } @ARTICLE{Demian2006, author = {Peter Demian and Renate Fruchter}, title = {Finding and Understanding Reusable Designs from Large Hierarchical Repositories}, journal = {Information Visualization}, year = {2006}, volume = {5}, pages = {28--46}, number = {1}, abstract = {This paper describes a prototype called CoMem (Corporate Memory) that supports the finding and understanding of useful items in large hierarchical repositories. The particular domain is civil engineering design, and the prototype is designed specifically to support design reuse in building construction projects. However, the underlying visualization and interaction principals behind CoMem are generalizable to the ubiquitous task of finding and understanding useful information in large hierarchical repositories. To support the finding, the entire hierarchy is visualized using a squarified treemap. Once an item from the treemap is selected, CoMem supports the understanding of that item by identifying related items in the hierarchy and visualizing the selected item in the context of these related items in a node-link diagram. The paper concludes with a brief discussion of a usability evaluation of CoMem that supports the claim that finding and understanding improve the process of reuse, and that the described visualizations assist with finding and understanding.}, doi = {10.1057/palgrave.ivs.9500114} } @INPROCEEDINGS{Denier2009, author = {Simon Denier and Houari Sahraoui}, title = {Understanding the use of inheritance with visual patterns}, pages = {79-88}, abstract = {The goal of this work is to visualize inheritance in object-oriented programs to help its comprehension. We propose a single, compact view of all class hierarchies at once using a custom Sunburst layout. It enables to quickly discover interesting facts across classes while preserving the essential relationship between parent and children classes. We explain how standard inheritance metrics are mapped into our visualization. Additionally, we define a new metric characterizing similar children classes. Using these metrics and the proposed layout, a set of common visual patterns is derived. These patterns allow the programmer to quickly understand how inheritance is used and provide answers to some essential questions when performing program comprehension tasks. Our approach is evaluated through a case study that involves examples from large programs, demonstrating its scalability.}, doi = {10.1109/ESEM.2009.5316016}, year = {2009}, booktitle = {ESEM'09: Proceedings of the International Symposium on Empirical Software Engineering and Measurement}, publisher = {IEEE Computer Society}, isbn = {9781424448418} } @ARTICLE{deVienne2016, author = {Damien M. de Vienne}, title = {Lifemap: Exploring the entire Tree of Life}, journal = {PLOS Biology}, year = {2016}, volume = {14}, pages = {e2001624}, number = {12}, abstract = {The Tree of Life (ToL) is meant to be a unique representation of the evolutionary relationships between all species on earth. Huge efforts are made to assemble such a large tree, helped by the decrease of sequencing costs and improved methods to reconstruct and combine phylogenies, but no tool exists today to explore the ToL in its entirety in a satisfying manner. By combining methods used in modern cartography, such as OpenStreetMap, with a new way of representing tree-like structures, I created Lifemap, a tool allowing the exploration of a complete representation of the ToL (between 800,000 and 2.2 million species depending on the data source) in a zoomable interface. A server version of Lifemap also allows users to visualize their own trees. This should help researchers in ecology and evolutionary biology in their everyday work, but may also permit the diffusion to a broader audience of our current knowledge of the evolutionary relationships linking all organisms.}, doi = {10.1371/journal.pbio.2001624} } @INPROCEEDINGS{Devroye1995, author = {Luc Devroye and Paul Kruszewski}, title = {The botanical beauty of random binary trees}, pages = {166--177}, abstract = {We present a simple mechanism for quickly rendering computer images of botanical trees based on random binary trees commonly found in computer science. That is, we visualize abstract binary trees as botanical ones. We generate random binary trees by splitting based upon the beta distribution, and obtain the standard binary search trees as a special case. We draw them in PostScript to resemble actual botanical trees found in nature. Through flexible parameterization and extensive randomization, we can produce a rich collection of images.}, doi = {10.1007/BFb0021801}, year = {1995}, booktitle = {GD'95: Proceedings of the Symposium on Graph Drawing}, editor = {Franz J. Brandenburg}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540607236}, } @INPROCEEDINGS{Dix2000, author = {Alan Dix and Russell Beale and Andy Wood}, title = {Architectures to make simple visualisations using simple systems}, pages = {51--60}, abstract = {In previous work, the first author argued for simple lightweight visualisations. These are surprisingly complex to produce due to the need for infrastructure to read files, etc. onCue, a desktop 'agent', aids the rapid production of such visualisations and their integration with desktop and Internet applications. Two examples are used dancing histograms for 2D tables and pieTrees for hierarchical numeric data. A major focus is the importance of architecture, both that of onCue itself and the underlying component infrastructure on which it is built - separation of concerns, mixed initiative computation and plug-and-play components lead to easily produced and easily used systems.}, doi = {10.1145/345513.345250}, year = {2000}, booktitle = {AVI'00: Proceedings of the Working Conference on Advanced Visual Interfaces}, editor = {Vito Di Ges\'u and Stefano Levialdi and Laura Tarantino}, publisher = {ACM Press}, isbn = {1581132522} } @INPROCEEDINGS{Dmitrieva2009, author = {Julia Dmitrieva and Fons J. Verbeek}, title = {Node-Link and Containment Methods in Ontology Visualization}, abstract = {OWL Ontology language can be very expressive. This could provide difficulty in ontology understanding process. We belief, that an ontology visualization equipped with intuitive interactions can simplify this process, and help the user during ontology exploration and development. We introduce an approach representing an ontology with two different tree visualization techniques: the node-link technique, and the containment technique. These two representations show the structure of an ontology differently. The former, represents an ontology as a graph structure. This graph structure, based on the ontology hierarchy and properties, can be explored in different geometries: Euclidean, hyperbolic and spherical. The second representation shows only the hierarchical structure. The design of the containment approach is implemented in a non-standard way. In place of traditional two-dimensional space-filling techniques, we elaborate on the sphere-packing approach and make our hierarchy visualization three-dimensional. We augment this technique with the semantic zoom functionality, where the level of detail is a function of a distance from the viewer.}, url = {http://ceur-ws.org/Vol-529/owled2009_submission_9.pdf}, year = {2009}, booktitle = {OWLED'09: Proceedings of the International Workshop on OWL: Experiences and Directions}, editor = {Rinke Hoekstra and Peter F. Patel-Schneider}, publisher = {CEUR Workshop Proceedings}, } @INPROCEEDINGS{Draper2008, author = {Geoffrey M. Draper and Richard F. Riesenfeld}, title = {Interactive Fan Charts: A Space-Saving Technique for Genealogical Graph Exploration}, abstract = {Fan charts are a popular method for displaying family trees in a compact way. We extend the concept of fan charts to include a number of interactive metaphors, thus transforming what was a static display medium into an interactive tool for browsing and editing genealogical data.}, url = {http://fht.byu.edu/prev_workshops/workshop08/papers/1/1-1.pdf}, year = {2008}, booktitle = {FHTW'08: Proceedings of the Workshop on Technology for Family History and Genealogical Research} } @ARTICLE{Duarte2014, author = {Felipe S. L. G. Duarte and Fabio Sikansi and Francisco M. Fatore and Samuel G. Fadel and Fernando V. Paulovich}, title = {Nmap: A Novel Neighborhood Preservation Space-filling Algorithm}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2014}, volume = {20}, pages = {2063--2071}, number = {12}, abstract = {Space-filling techniques seek to use as much as possible the visual space to represent a dataset, splitting it into regions that represent the data elements. Amongst those techniques, Treemaps have received wide attention due to its simplicity, reduced visual complexity, and compact use of the available space. Several different Treemap algorithms have been proposed, however the core idea is the same, to divide the visual space into rectangles with areas proportional to some data attribute or weight. Although pleasant layouts can be effectively produced by the existing techniques, most of them do not take into account relationships that might exist between different data elements when partitioning the visual space. This violates the distance-similarity metaphor, that is, close rectangles do not necessarily represent similar data elements. In this paper, we propose a novel approach, called Neighborhood Treemap (Nmap), that seeks to solve this limitation by employing a slice and scale strategy where the visual space is successively bisected on the horizontal or vertical directions and the bisections are scaled until one rectangle is defined per data element. Compared to the current techniques with the same similarity preservation goal, our approach presents the best results while being two to three orders of magnitude faster. The usefulness of Nmap is shown by two applications involving the organization of document collections and the construction of cartograms illustrating its effectiveness on different scenarios.}, doi = {10.1109/TVCG.2014.2346276} } @ARTICLE{Ducheyne2009, author = {Steffen Ducheyne}, title = {To treat of the world -- {Paul Otlet}'s ontology and epistemology and the circle of knowledge}, journal = {Journal of Documentation}, year = {2009}, volume = {65}, pages = {223-244}, number = {2}, abstract = {The purpose of this paper is to document how Paul Otlet, founding-father of what is termed at present as information science, attempted to provide a complete image of the world (and reality in general) by establishing the scientific discipline he dubbed documentation. The paper also aims to focus on how Otlet represented human knowledge and reality in a systematic and unified way. Most importantly, it is shown that Otlet's views on documentation were immersed in a cosmological, objectivist, humanitarian and ontological framework that is alien to contemporary information science. Correspondingly, his alleged affinity with positivism is reassessed.}, doi = {10.1108/00220410910937598} } @INPROCEEDINGS{Duncan2010, author = {Christian A. Duncan and David Eppstein and Michael T. Goodrich and Stephen G. Kobourov and Martin N\"ollenburg}, title = {Drawing Trees with Perfect Angular Resolution and Polynomial Area}, pages = {183--194}, abstract = {We study methods for drawing trees with perfect angular resolution, i.e., with angles at each vertex, v, equal to $2\pi /d(v)$. We show: 1.Any unordered tree has a crossing-free straight-line drawing with perfect angular resolution and polynomial area. 2. There are ordered trees that require exponential area for any crossing-free straight-line drawing having perfect angular resolution. 3. Any ordered tree has a crossing-free Lombardi-style drawing (where each edge is represented by a circular arc) with perfect angular resolution and polynomial area. Thus, our results explore what is achievable with straight-line drawings and what more is achievable with Lombardi-style drawings, with respect to drawings of trees with perfect angular resolution.}, doi = {10.1007/978-3-642-18469-7_17}, year = {2010}, booktitle = {GD'10: Proceedings of the International Symposium on Graph Drawing}, editor = {Ulrik Brandes and Sabine Cornelsen}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642184680}, } @INPROCEEDINGS{Dwyer2010, author = {Tim Dwyer and Kim Marriott and Peter Sbarski}, title = {{Hi-Tree} Layout Using Quadratic Programming}, pages = {212--219}, abstract = {Horizontal placement of nodes in tree layout or layered drawings of directed graphs can be modelled as a convex quadratic program. Thus, quadratic programming provides a declarative framework for specifying such layouts which can then be solved optimally with a standard quadratic programming solver. While slower than specialized algorithms, the quadratic programming approach is fast enough for practical applications and has the great benefit of being flexible yet easy to implement with standard mathematical software. We demonstrate the utility of this approach by using it to layout hi-trees. These are a tree-like structure with compound nodes recently introduced for visualizing the logical structure of arguments and of decisions.}, doi = {10.1007/978-3-642-14600-8_20}, year = {2010}, booktitle = {Diagrammatic Representation and Inference: Proceedings of the International Conference Diagrams 2010}, editor = {Ashok K. Goel and Mateja Jamnik and N. Hari Narayanan}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {364214599X}, } @ARTICLE{Eades1992, author = {Peter Eades}, title = {Drawing free trees}, journal = {Bulletin of the Institute of Combinatorics and its Applications}, year = {1992}, volume = {5}, pages = {10--36}, abstract = {Trees are models of various structures in computing and it is not surprising that considerable efforts have been made towards effective drawing algorithms for them. This paper discusses drawing algorithms for "free trees", that is, trees with no special root. The aim of these algorithms is to provide a drawing which satisfies several aesthetic criteria, such as avoiding edge crossings, minimizing variance in edge length, and keeping vertices a resonable distance apart. In this paper we measure the effectiveness of the algorithm presented by proving or disproving that they achieve such criteria.}, url = {http://www.informatik.uni-rostock.de/~hs162/treeposter/scans/Eades1992.pdf} } @INPROCEEDINGS{Eades1992a, author = {Peter Eades and Tao Lin and Xuemin Lin}, title = {Minimum size h-v drawings}, pages = {386--394}, abstract = {Trees are one of the most commonly used structures in computing, and many techniques for the visualization of trees are available. These techniques usually aim to find an aestetically pleasing layout for a tree on a screen of limited size. This paper presents an algorithm for "h-v tree" drawing. The algorithm can be used to find a drawing of minimal "size", where "size" has a variety of definitions (inclusing area). Two applications of the algorithm are explicitly presented.}, url = {http://www.informatik.uni-rostock.de/~hs162/treeposter/scans/Eades1992a.pdf}, year = {1992}, booktitle = {AVI'92: Proceedings of the Workshop on Advanced Visual Interfaces}, editor = {Tiziana Catarci and Maria Francesca Costabile and Stefano Levialdi}, publisher = {World Scientific Publishing}, isbn = {9810211236} } @ARTICLE{Eades1993, author = {Peter Eades and Tao Lin and Xuemin Lin}, title = {Two Tree Drawing Conventions}, journal = {International Journal of Computational Geometry and Applications}, year = {1993}, volume = {3}, pages = {133--153}, number = {2}, abstract = {Rooted trees abound in computing and it is often necessary to draw them for visualization and documentation purposes. In the classical convention for tree drawing, the tree is drawn in a "level" fashion, with nodes (represented by boxes) at depth k lying on a horizontal line at a distance of k units below the root. The parent-child relationships are represented by lines between the boxes. Several algorithms have been developed for constructing a compact layout of a tree in the classical convention. In this paper we investigate algorithms for drawing trees according to two new conventions. In the inclusion convention, nodes are represented by boxes, and the parent-child relationship is represented by inclusion of one box in another. The tip-over convention again represents nodes as boxes, and, like the classical convention, represents the parent-child relationship by lines between the boxes; however, we allow siblings to be arranged vertically rather than horizontally. For many of the cases which arise in visualization of trees (for example, binary trees with textual information at the leaves) we present polynomial time algorithms. However, the general problem of finding minimum size layouts for either of the new conventions is shown to be NP-hard.}, doi = {10.1142/S0218195993000099} } @INPROCEEDINGS{EdChi1998, author = {Ed H. Chi and James Pitkow and Jock Mackinlay and Peter Pirolli and Rich Gossweiler and Stuart K. Card}, title = {Visualizing the evolution of Web ecologies}, pages = {400--407}, abstract = {Several visualizations have emerged which attempt to visualize all or part of the World Wide Web. Those visualizations, however, fail to present the dynamically changing ecology of users and documents on the Web. We present new techniques for Web Ecology and Evolution Visualization (WEEV). Disk Trees represent a discrete time slice of the Web ecology. A collection of Disk Trees forms a Time Tube, representing the evolution of the Web over longer periods of time. These visualizations are intended to aid authors and webmasters with the production and organization of content, assist Web surfers making sense of information, and help researchers understand the Web.}, doi = {10.1145/274644.274699}, year = {1998}, booktitle = {CHI'98: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems}, editor = {Clare-Marie Karat and Arnold Lund and Jo\"elle Coutaz and John Karat}, publisher = {ACM Press}, isbn = {0201309874} } @MISC{Eichhorn2006, author = {Elisabeth Eichhorn}, title = {Family tree visualization}, url = {http://www.elisabetheichhorn.de/_en/projekte/weiter/stammbaum/stammbaum.html}, year = {2006}, note = {retrieved 26-APR-2010} } @INPROCEEDINGS{Elzen2011, author = {Stef van den Elzen and Jarke J. van Wijk}, title = {{BaobabView}: Interactive construction and analysis of decision trees}, pages = {151--160}, abstract = {We present a system for the interactive construction and analysis of decision trees that enables domain experts to bring in domain specific knowledge. We identify different user tasks and corresponding requirements, and develop a system incorporating a tight integration of visualization, interaction and algorithmic support. Domain experts are supported in growing, pruning, optimizing and analysing decision trees. Furthermore, we present a scalable decision tree visualization optimized for exploration. We show the effectiveness of our approach by applying the methods to two use cases. The first case illustrates the advantages of interactive construction, the second case demonstrates the effectiveness of analysis of decision trees and exploration of the structure of the data.}, doi = {10.1109/VAST.2011.6102453}, year = {2011}, booktitle = {VAST'11: Proceedings of the IEEE Conference on Visual Analytics Science and Technology}, editor = {Silvia Miksch and Matt Ward}, publisher = {IEEE Computer Society}, isbn = {9781467300148} } @MASTERSTHESIS{Engdahl2005, author = {Bj\"orn Engdahl}, title = {Ordered and Unordered Treemap. Algorithms and Their Applications on Handheld Devices}, school = {Royal Institute of Technology, Stockholm, Sweden}, year = {2005}, abstract = {This thesis describes a way to visualize hierarchical structures on PDAs using Treemaps. A new ordered layout algorithm for treemaps, called Split Layout, is presented. Traditionally, treemap algorithms have exhibited a trade off between good aspect ratio and ordered layout. The new Split Layout is compared to five published treemap algorithms. Properties such as avarage aspect ratio, stability, run time and readability are measured, and it is shown that the new Split Layout performs better than any known ordered layout. The average aspect ratio is about 23\% better and the stability increased between 28\% and 40\%. A user study was performed to measure the quality of the ordering of the new algorithm. 30 users gave a total of 360 measured response times, and it was found that the median time to locate a specific rectangle in the treemap only took 0.14 seconds (5\%) longer for the Split Layout than for the Pivot by Split Size algorithm. The technique was implemented on a PDA and used for visualizing threaded discussion forums. User studies confirm that the concept on using treemaps on PDAs looks promising. The contents of the forum was easily grasped, even though the number of articles exceeded one hundred.}, url = {http://w3.nada.kth.se/utbildning/grukth/exjobb/rapportlistor/2005/rapporter05/engdahl_bjorn_05033.pdf} } @ARTICLE{Engel2011, author = {Daniel Engel and Rene Rosenbaum and Bernd Hamann and Hans Hagen}, title = {Structural Decomposition Trees}, journal = {Computer Graphics Forum}, year = {2011}, volume = {30}, pages = {921--930}, number = {3}, abstract = {Researchers and analysts in modern industrial and academic environments are faced with a daunting amount of multi-dimensional data. While there has been significant development in the areas of data mining and knowledge discovery, there is still the need for improved visualizations and generic solutions. The state-of-the-art in visual analytics and exploratory data visualization is to incorporate more profound analysis methods while focusing on fast interactive abilities. The common trend in these scenarios is to either visualize an abstraction of the data set or to better utilize screen-space. This paper presents a novel technique that combines clustering, dimension reduction and multi-dimensional data representation to form a multivariate data visualization that incorporates both detail and overview. This amalgamation counters the individual drawbacks of common projection and multi-dimensional data visualization techniques, namely ambiguity and clutter. A specific clustering criterion is used to decompose a multi-dimensional data set into a hierarchical tree structure. This decomposition is embedded in a novel Dimensional Anchor visualization through the use of a weighted linear dimension reduction technique. The resulting Structural Decomposition Tree (SDT) provides not only an insight of the data set's inherent structure, but also conveys detailed coordinate value information. Further, fast and intuitive interaction techniques are explored in order to guide the user in highlighting, brushing, and filtering of the data.}, doi = {10.1111/j.1467-8659.2011.01941.x} } @MISC{Eppstein2009, author = {David Eppstein}, title = {Visualizing {BFS} as a spiral}, url = {http://11011110.livejournal.com/171440.html}, year = {2009}, note = {retrieved 26-APR-2010} } @BOOK{Ernst1985, title = {Bomen van {Pythagoras} -- Variaties van {Jos de Mey}}, publisher = {Aramith Uitgevers Amsterdam}, year = {1985}, author = {Bruno Ernst}, isbn = {9068340204} } @MISC{Ernst2004, author = {Bruno Ernst}, title = {De ware geschiedenis van de {Boom van Pythagoras}}, howpublished = {Bruno's columns}, year = {2004}, abstract = {The Pythagoras tree is a plane fractal constructed from squares. Invented by the Dutch mathematics teacher Albert E. Bosman in 1942, it is named after the ancient Greek mathematician Pythagoras because each triple of touching squares encloses a right triangle, in a configuration traditionally used to depict the Pythagorean theorem.}, url = {http://www.arsetmathesis.nl/bruno0402.htm} } @INPROCEEDINGS{Etemad2009, author = {Katayoon Etemad and Sheelagh Carpendale}, title = {{ShamsehTrees}: Providing Hierarchical Context for Nodes of Interest}, pages = {293--300}, abstract = {Visualizations of hierarchical data usually focus on conveying structure. However, with really large hierarchies, layouts tend to become overcrowded, making it difficult to see details about specific nodes. In contrast, ShamsehTrees focus on layouts centered on a node of interest, provide interactive nested layouts that were inspired by artistic and natural floral patterns, and make use of the natural symmetries in phyllotactic patterns. Instead of emphasizing overall tree structure, these layouts are created to make the most space available for the node of interest. The basic layout is comprised of nested circles that are centered on the node of interest. After selecting a new node of interest, the resizing and repositioning of nodes is animated as they transition to the new layout.}, } year = {2009}, booktitle = {Bridges'09: Proceedings of the Bridges Conference on Mathematics, Music, Art, Architecture, Culture}, editor = {Craig S. Kaplan and Reza Sarhangi}, publisher = {Tarquin Books}, isbn = {9780966520194}, url = {http://bridgesmathart.org/2009/2009proceedings.pdf} } @MISC{Etemad2010, author = {Katayoon Etemad and Sheelagh Carpendale}, title = {Symmetry and Node Focused Visualization of Large Trees}, howpublished = {poster presentation at the GRAND NCE Annual Conference}, year = {2010}, abstract = {In this paper, we take a different approach to visualizing very large trees. To facilitate presentation and exploration of massive hierarchical datasets such as linguistic and genealogical hierarchies, our approach considers drawing layouts of tree-cuts as a function of a node-of-interest or NOI, and uses interaction to support rapid access to the entire tree. Instead of emphasizing overall tree structure, our layout is designed to make the most space available for the node-of-interest and its immediate ancestors and descendants. Inspired from Persian floral patterns, we describe the development of ShamsehTree and PaisleyTree, showing how the use of symmetry can provide new structures for tree layouts.}, url = {http://innovis.cpsc.ucalgary.ca/innovis/uploads/Publications/Publications/symmetry-poster.pdf} } @ARTICLE{Etemad2014, author = {Katayoon Etemad and Dominikus Baur and John Brosz and Sheelagh Carpendale and Faramarz F. Samavati}, title = {{PaisleyTrees}: A Size-Invariant Tree Visualization}, journal = {EAI Transactions on Creative Technologies}, year = {2014}, volume = {1}, number = {1}, abstract = {Squeezing large tree structures into suitable visualizations has been a perennial problem. In response to this challenge, we present PaisleyTrees, a size-invariant tree visualization. PaisleyTrees integrate node-of-interest focus with tree-cut presentations to support rapid tree navigation without resorting to zooming and panning. This visualization offers the ability to work with trees of arbitrary depth and breadth, and maintains legibility for displayed elements. These advantages are achieved by using a hybrid layout, inspired by traditional Paisley patterns, that combines node-link, nested and djacency-based tree layout techniques, and offers both depth and breadth elision.}, doi = {10.4108/ct.1.1.e2} } @INPROCEEDINGS{Fahrenholtz1995, author = {Dietrich Fahrenholtz and Volker Haarslev}, title = {Visualization of {Strand}\texttrademark ~processes}, pages = {114--115}, abstract = {The paper describes a visualization tool that uses polar coordinates to create a circular shaped layout of large call trees of Strand programs. Due to the enormous amount of processes which are generated during execution of parallel Strand programs, conventional techniques to display call trees are over-charged. Because of this the tool `Polaranimation' was developed and implemented. One of its prominent features is the ability to display the complete call tree without loosing any vital information. Additionally, it provides debugging facilities and supports the performance tuning of parallel programs. A number of Strand programs have been written and a performance evaluation and comparison guided by `Polaranimation' was conducted.}, doi = {10.1109/VL.1995.520793}, year = {1995}, booktitle = {VL'95: Proceedings of the IEEE Symposium on Visual Languages}, editor = {Volker Haarslev}, publisher = {IEEE Computer Society}, isbn = {0818670452} } @INCOLLECTION{Feinberg2010, author = {Jonathan Feinberg}, title = {Wordle}, chapter = {3}, pages = {37--58}, url = {http://static.mrfeinberg.com/bv_ch03.pdf}, publisher = {O'Reilly}, year = {2010}, editor = {Julie Steele and Noah Iliinsky}, isbn = {9781449379872}, abstract = {Visualization is the graphic presentation of data -- portrayals meant to reveal complex information at a glance. Think of the familiar map of the New York City subway system, or a diagram of the human brain. Successful visualizations are beautiful not only for their aesthetic design, but also for elegant layers of detail that efficiently generate insight and new understanding. This book examines the methods of two dozen visualization experts who approach their projects from a variety of perspectives -- as artists, designers, commentators, scientists, analysts, statisticians, and more. Together they demonstrate how visualization can help us make sense of the world. Contributors include: Nick Bilton, Michael E. Driscoll, Jonathan Feinberg, Danyel Fisher, Jessica Hagy, Gregor Hochmuth, Todd Holloway, Noah Iliinsky, Eddie Jabbour, Valdean Klump, Aaron Koblin, Robert Kosara, Valdis Krebs, JoAnn Kuchera-Morin et al., Andrew Odewahn, Adam Perer, Anders Persson, Maximilian Schich, Matthias Shapiro, Julie Steele, Moritz Stefaner, Jer Thorp, Fernanda Viegas, Martin Wattenberg, and Michael Young.}, booktitle = {Beautiful Visualization} } @INPROCEEDINGS{Fischer1980, author = {Michael J. Fischer and Michael S. Paterson}, title = {Optimal Tree Layout (Preliminary Version)}, pages = {177--189}, abstract = {We consider the problem of finding a minimal cost layout of a tree in Euclidian d-space. A tree is an acyclic undirected edge-weighted graph, and a layout is an assignment of a point in d-dimensional Euclidian space to each of the nodes of the tree. The ``length'' of an edge in the layout is the “distance” between its endpoints as measured by some norm. The cost of an edge is its length times its weight, and the cost of the whole layout is the sum of the costs of all the edges. We assume the positions of certain nodes are fixed in advance, and we wish to place the remaining nodes so as to minimize the cost of the layout.}, doi = {10.1145/800141.804665}, year = {1980}, booktitle = {STOC'80: Proceedings of the Annual ACM Symposium on Theory of Computing}, editor = {Raymond E. Miller and Seymour Ginsburg and Walter A. Burkhard and Richard J. Lipton}, publisher = {ACM}, isbn = {0897910176} } @INPROCEEDINGS{Fischer2012, author = {Fabian Fischer and Johannes Fuchs and Florian Mansmann}, title = {{ClockMap}: Enhancing Circular {Treemaps} with Temporal Glyphs for Time-Series Data}, pages = {97--101}, abstract = {Treemaps are a powerful method to visualize especially time-invariant hierarchical data. Most attention is drawn to rectangular treemaps, because their space-filling layouts provide good scalability with respect to the amount of data that can be displayed. Since circular treemaps sacrifice the space-filling property and since higher level circles only approximately match the aggregated size of their descendants, they are rarely used in practice. However, for drawing circular glyphs their shape preserving property can outweigh these disadvantages and facilitate comparative tasks within and across hierarchy levels. The interactive ClockMap visualization effectively supports the user in exploring and finding patterns in hierarchical time-series data through drill-down, semantic zoom and details-on-demand. In this study, the technique's applicability is demonstrated on a real-world dataset about network traffic of a large computer network and its advantages and disadvantages are discussed in the context of alternative layouts.}, doi = {10.2312/PE/EuroVisShort/EuroVisShort2012/097-101}, year = {2012}, booktitle = {EuroVis'12: Short Paper Proceedings of the Eurographics/IEEE Symposium on Visualization}, editor = {Miriah Meyer and Tino Weinkauf}, publisher = {Eurographics Association}, isbn = {9783905673913} } @INPROCEEDINGS{Ganascia2004, author = {Jean-Gabriel Ganascia}, title = {{RECIT}: REpr\'esentation Cartographique et Insulaire de Textes}, pages = {59--70}, abstract = {Experiences show that most readers are lost in electronic text, because they lack of global information. As a consequence, many people print electronic texts before reading them. This strange phenomenon was not predicted in the past and it could preclude the expansion of electronic reading. We propose here a way to provide some visualization of the structure of the document. That corresponds to the cartography of its overall organization. Our hope is that it could help to orient in electronic texts and consequently to facilitate electronic reading. This paper describes the origins of difficulties and then it presents all the technical details of the proposed solution.}, url = {http://hal.archives-ouvertes.fr/docs/00/06/25/35/PDF/sic_00001258.pdf}, year = {2004}, booktitle = {CIFT'03: Proceedings of the Colloque International sur la Fouille de Texte} } @INPROCEEDINGS{Ganascia2006, author = {Jean-Gabriel Ganascia}, title = {AC$^3$ - Automatic Cartography of Cultural Contents}, pages = {253--263}, abstract = {Experiences with e-books show that the principle obstacle to electronic reading is neither the weight, nor the autonomy or the discomfort of reading on screen, but the absence of reference mark which makes it possible to replace the current window of reading in the whole of the book. We present an automatic cartography of electronic documents which constitutes an attempt to facilitate navigation, reading and memorization of contents. It is to automatically build a singular picture which is designed to be associated to our remembering of each document, i.e. to our mental image. This picture corresponds to the cartography of an island. Its shape is build from the document structure; its coloring reflects the affective content of the text extracted by keywords spotting techniques while icons associated to document topics are added to textual legends as in ancient geographical maps.}, doi = {10.1007/978-3-540-71027-1_22}, year = {2006}, booktitle = {VIEW'06: Proceedings of the Visual Information Expert Workshop}, editor = {Pierre P. L\'evy and B\'en\'edicte Le Grand and Fran\c{c}ois Poulet and Michel Soto and Laszlo Darago and Laurent Toubiana and Jean-Fran\c{c}ois Vibert}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3540710264}, } @MISC{Ganascia2012, author = {Jean-Gabriel Ganascia}, title = {Memory Islands -- Ontology display}, url = {http://www-poleia.lip6.fr/~polyle/NewEX/v11012012/result.html}, year = {2012}, note = {retrieved 26-JAN-2012}, abstract = {With the concept of Memory Islands, the ACASA team propose a new tree visualization approach that is based on cartography, i.e. on a spatialization of abstract data structures, mainly trees. The hypothesis on which the notion Memory Island is based is that the spatialization helps to memorize contents. This notion of Memory Island is applied to ontology visualization, which could help to access to many online documents.} } @BOOK{Gannett1903, title = {Twelfth census of the United States, taken in the year 1900. Statistical atlas}, publisher = {U.S. Census Office Washington}, year = {1903}, author = {Henry Gannett} } @ARTICLE{Garg1996, author = {Ashim Garg and Michael T. Goodrich and Roberto Tamassia}, title = {Planar Upward Tree Drawings with Planar Area}, journal = {International Journal of Computational Geometry and Applications}, year = {1996}, volume = {6}, pages = {333--356}, number = {3}, abstract = {Rooted trees are usually drawn planar and upward, i.e., without crossings and with-out any parent placed below its child. In this paper we investigate the area requirement of planar upward drawings of rooted trees. We give tight upper and lower bounds on the area of various types of drawings, and provide linear-time algorithms for constructing optimal area drawings. Let T be a bounded-degree rooted tree with N nodes. Our results are summarized as follows: We show that T admits a planar polyline upward grid drawing with area O(N), and with width O(N*alpha) for any prespecified constant a such that 00, the distance between any two vertices is at least 1/1+e the length of the longest edge in the path connecting them. (1+e)-EMST drawings are good approximations of Euclidean minimum spanning trees. While it is known that only trees with bounded degree have a Euclidean minimum spanning tree realization, we show that every tree T has a (1+e)-EMST drawing for any given e>0. We also present drawing algorithms that compute (1+e)-EMST drawings of trees with bounded degree in polynomial area. As a byproduct of one of our techniques, we improve the best known area upper bound for Euclidean minimum spanning tree realizations of complete binary trees.}, doi = {10.1007/978-3-642-17514-5_6}, year = {2010}, booktitle = {ISAAC'10: Proceedings of the International Symposium on Algorithms and Computations}, editor = {Otfried Cheong and Kyung-Yong Chwa and Kunsoo Park}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3642175139}, } @ARTICLE{Giacomo2012, author = {Emilio Di Giacomo and Walter Didimo and Giuseppe Liotta and Henk Meijer}, title = {Drawing a Tree as a Minimum Spanning Tree Approximation}, journal = {Journal of Computer and System Sciences}, year = {2012}, volume = {78}, pages = {491--503}, number = {2}, abstract = {We introduce and study (1+e)-EMST drawings, i.e., planar straight-line drawings of trees such that, for any fixed e>0, the distance between any two vertices is at least View the MathML source the length of the longest edge in the path connecting them. (1+e)-EMST drawings are good approximations of Euclidean minimum spanning trees. While it is known that only trees with bounded degree have a Euclidean minimum spanning tree realization, we show that every tree T has a (1+e)-EMST drawing for any given e>0. We also present drawing algorithms that compute (1+e)-EMST drawings of trees with bounded degree in polynomial area. As a byproduct of one of our techniques, we improve the best known area upper bound for Euclidean minimum spanning tree realizations of complete binary trees.}, doi = {10.1016/j.jcss.2011.06.001} } @ARTICLE{Goertler2018, author = {Jochen G\"ortler and Christoph Schulz and Daniel Weiskopf and Oliver Deussen}, title = {Bubble {T}reemaps for Uncertainty Visualization}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2018}, volume = {24}, pages = {719--728}, number = {1}, abstract = {We present a novel type of circular treemap, where we intentionally allocate extra space for additional visual variables. With this extended visual design space, we encode hierarchically structured data along with their uncertainties in a combined diagram. We introduce a hierarchical and force-based circle-packing algorithm to compute Bubble Treemaps, where each node is visualized using nested contour arcs. Bubble Treemaps do not require any color or shading, which offers additional design choices. We explore uncertainty visualization as an application of our treemaps using standard error and Monte Carlo-based statistical models. To this end, we discuss how uncertainty propagates within hierarchies. Furthermore, we show the effectiveness of our visualization using three different examples: the package structure of Flare, the S&P 500 index, and the US consumer expenditure survey.}, doi = {10.1109/TVCG.2017.2743959} } @ARTICLE{Gordon1984, author = {Dan Gordon and Israel Koren and Gabriel M. Silberman}, title = {Embedding Tree Structures in {VLSI} Hexagonal Arrays}, journal = {IEEE Transactions on Computers}, year = {1984}, volume = {C-33}, pages = {104--107}, number = {1}, abstract = {Tree structures have been proposed for special-purpose and general-purpose multiprocessors due to their desirable property of logarithmic path from the root to any leaf element. Since only local communication among processors is needed in tree structures, they are well suited for the VLSI technology. Such an implementation requires an area-economical mapping of a tree on a plane. Novel mapping schemes for trees onto hexagonal arrays (or grids) and appropriate algorithms are proposed here and shown to be superior over known mappings on square arrays (or grids).}, doi = {10.1109/TC.1984.5009319} } @ARTICLE{Gordon1987, author = {Dan Gordon}, title = {Efficient Embeddings of Binary Trees in {VLSI} Arrays}, journal = {IEEE Transactions on Computers}, year = {1987}, volume = {C-36}, pages = {1009--1018}, number = {9}, abstract = {We consider the problem of embedding a complete binary tree in squareor hexagonally-connected VLSI arrays Of processing elements (PE's). This problem can be solved in a radically different manner from current layout techniques which are aimed at laying out a given graph in the plane. The difference is due to the fact that a PE can be used both as a tree node and as a connecting element between distant nodes. New embedding schemes are presented in which (asymptotically) 100 percent of the PE's are utilized as tree nodes. This is a significant savings over known schemes, which achieve 50 percent utilization (the well-known H-tree) and 71 percent for some hexagonal schemes. These schemes also speed up signal propagation from the root to the leaves.}, doi = {10.1109/TC.1987.5009532} } @TECHREPORT{Gotz2011, author = {David Gotz}, title = {Dynamic Voronoi Treemaps: A Visualization Technique for Time-Varying Hierarchical Data}, institution = {IBM Research}, year = {2011}, number = {RC25132}, abstract = {Treemaps are a widely used technique for the visualization of hierarchical data. In general, these techniques perform a space-filling recursive subdivision of a 2D space where the sizes of the created regions correspond to values of a particular data attribute. Several subdivision algorithms have been proposed to optimize specific criteria, such as region aspect ratio or stability. However, these goals are often contradictory. For example, existing layout algorithms that optimize for aspect ratio -- important for legibility -- are typically not stable. For this reason, Treemaps are rarely used in animated displays of time-variant data. When they are applied to dynamic data sets, unstable Treemap layout algorithms produce poorly animated transitions that include discontinuous jumps in region position when values change. This paper introduces a new technique called Dynamic Voronoi Treemaps. Our layout algorithm is specifically designed to support smooth, real-time animation of time varying hierarchical data while maintaining desirable aspect ratios. We describe our novel approach and outline how it overcomes key limitations of prior Voronoi-based Treemap work to enable the visualization of dynamic data. Results from an evaluation study of the technique are provided along with a brief use case highlighting a real-world application of Dynamic Voronoi Treemaps.}, url = {http://domino.watson.ibm.com/library/cyberdig.nsf/papers/82B477237B0FBED485257868004C1635} } @INPROCEEDINGS{Granitzer2004, author = {Michael Granitzer and Wolfgang Kienreich and Vedran Sabol and Keith Andrews and Werner Klieber}, title = {Evaluating a System for Interactive Exploration of Large, Hierarchically Structured Document Repositories}, pages = {127--134}, abstract = {The InfoSky visual explorer is a system enabling users to interactively explore large, hierarchically structured document collections. Similar to a real-world telescope, InfoSky employs a planar graphical representation with variable magnification. Documents of similar content are placed close to each other and displayed as stars, while collections of documents at a particular level in the hierarchy are visualised as bounding polygons. Usability testing of an early prototype implementation of InfoSky revealed several design issues which prevented users from fully exploiting the power of the visual metaphor. Evaluation results have been incorporated into an advanced prototype, and another usability test has been conducted. A comparison of test results demonstrates enhanced system performance and points out promising directions for further work.}, doi = {10.1109/INFVIS.2004.19}, year = {2004}, booktitle = {InfoVis'04: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Matthew O. Ward and Tamara Munzner}, publisher = {IEEE Computer Society}, isbn = {0780387791} } @ARTICLE{Gregori1989, author = {Angelo Gregori}, title = {Unit-length embedding of binary trees on a square grid}, journal = {Information Processing Letters}, year = {1989}, volume = {31}, pages = {167--173}, number = {4}, abstract = {We give a proof of the fact that determining whether or not a given binary tree has a grid embedding with edges of unit length is an NP-complete problem. The proof follows an idea indicated by Bhatt and Cosmadakis in [1], which has been implemented using a new building block called U-tree.}, doi = {10.1016/0020-0190(89)90118-X} } @INPROCEEDINGS{Grivet2004, author = {S\'ebastien Grivet and David Auber and Jean-Philippe Domenger and Guy Melan\c{c}on}, title = {Bubble Tree Drawing Algorithm}, pages = {633--641}, abstract = {In this paper, we present an algorithm, called Bubble Tree, for the drawing of general rooted trees. A large variety of algorithms already exists in this field. However, the goal of this algorithm is to obtain a better drawing which makes a trade off between the angular resolution and the length of the edges. We show that the Bubble Tree drawing algorithm provides a planar drawing with at most one bend per edge in linear running time.}, doi = {10.1007/1-4020-4179-9_91}, year = {2004}, booktitle = {ICCVG'04: Proceedings of the International Conference on Computer Vision and Graphics}, editor = {Konrad Wojciechowski and Bogdan Smolka and Henryk Palus and Ryszard Kozera and Wladyslaw Skarbek and Lyle Noakes}, publisher = {Springer}, isbn = {9781402041785}, } @ARTICLE{Hadlak2010, author = {Steffen Hadlak and Christian Tominski and Hans-J\"org Schulz and Heidrun Schumann}, title = {Visualization of attributed hierarchical structures in a spatiotemporal context}, journal = {International Journal of Geographical Information Science}, year = {2010}, volume = {24}, pages = {1497--1513}, number = {10}, abstract = {When visualizing data, spatial and temporal references of these data often have to be considered in addition to the actual data attributes. Nowadays, structural information is becoming more and more important. Hierarchies, for instance, are frequently applied to make large and complex data manageable. Hence, a visual depiction of hierarchical structures in space and time is required. While there are several techniques addressing specific aspects of spatiotemporal visualization, approaches that cope with space, time, data, and structure are rare. With this paper we take a step to fill this gap. By combining various well-established concepts we achieve a reasonably complete visualization of all of the aforementioned aspects, where our focus is on hierarchical structures. We embed hierarchies directly into regions of a map display using variants of the point-based layout. Layering and animation are applied to visualize temporal aspects. Depending on analysis goals, users can switch between representations that emphasize data attributes or hierarchical structures. Interaction techniques support users in navigating the data and their visualization. We demonstrate the usefulness of our approach by adapting it to implement a visualization for spatio-temporal human health data.}, doi = {10.1080/13658816.2010.510840} } @INPROCEEDINGS{Hahn2014, author = {Sebastian Hahn and Jonas Tr\"umper and Dominik Moritz and J\"urgen D\"ollner}, title = {Visualization of Varying Hierarchies by Stable Layout of {Voronoi Treemaps}}, pages = {50--58}, abstract = {Space-restricted techniques for visualizing hierarchies generally achieve high scalability and readability (e.g., tree maps, bundle views, sunburst). However, the visualization layout directly depends on the hierarchy, that is, small changes to the hierarchy can cause wide-ranging changes to the layout. For this reason, it is difficult to use these techniques to compare similar variants of a hierarchy because users are confronted with layouts that do not expose the expected similarity. Voronoi treemaps appear to be promising candidates to overcome this limitation. However, existing Voronoi treemap algorithms do not provide deterministic layouts or assume a fixed hierarchy. In this paper we present an extended layout algorithm for Voronoi treemaps that provides a high degree of layout similiarity for varying hierarchies, such as software-system hierarchies. The implementation uses a deterministic initial-distribution approach that reduces the variation in node positioning even if changes in the underlying hierarchy data occur. Compared to existing layout algorithms, our algorithm achieves lower error rates with respect to node areas in the case of weighted Voronoi diagrams, which we show in a comparative study.}, url = {http://www.hpi.uni-potsdam.de/doellner/publications/year/2014/2334/STMD2014.html}, year = {2014}, booktitle = {IVAPP'14: Proceedings of the International Conference on Information Visualization Theory and Applications}, editor = {Robert S. Laramee and Andreas Kerren and Jos\'e Braz}, publisher = {SCITEPRESS}, isbn = {9789897580055} } @INPROCEEDINGS{Hahn2017, author = {Sebastian Hahn and J\"urgen D\"ollner}, title = {{Hybrid-Treemap} Layouting}, pages = {79--83}, abstract = {This paper presents an approach for hybrid treemaps, which applies and combines several different layout principles within a single tree map in contrast to traditional treemap variants based on a single layout concept. To this end, we analyze shortcomings of state-of-the-art treemap algorithms such as Moore, Voronoi and Strip layouts. Based on a number of identified edge cases, we propose a combination of these different layout algorithms, individually selected for and applied on each sub hierarchy of the given treemap data. The selection decision is based on the number of items to be layouted as well as the aspect ratio of the containing visual elements. Futhermore, a layout quality score based on existing treemap layout metrics (e.g., average distance change, relative direction change, average aspect ratio) has been used to evaluate the results of the proposed hybrid layout algorithm and to demonstrate its usefulness applied on representative hierarchical data sets.}, doi = {10.2312/eurovisshort.20171137}, year = {2017}, booktitle = {EuroVis'17: Short Paper Proceedings of the Joint Eurographics - IEEE VGTC Conference on Visualization}, editor = {Barbora Kozl\'{\i}kov\'a and Tobias Schreck and Thomas Wischgoll}, publisher = {Eurographics Association}, isbn = {9783038680437} } @PATENT{Halachmi2000, author = {Avi Halachmi and Michael Jacovi and Menachem Shtalhaim and Sigalit Ur and Yoelle Maarek}, title = {Large tree structure visualization and display system}, number = {US 6104400}, year = {2000}, abstract = {System for the visualization of a large tree structure in which the selection of a center object (40) amongst the objects of the large tree structure enables n levels of descendants from the center object to be visualized on a screen together with the center object, the system has a visualization control in computer memory enabling the objects of a given level corresponding to the children of a parent object of the immediate higher level to be visualized in a fan-shaped area centered around the parent object. A scrollbar associated with the parent object enables all the children of a parent object to be scrolled in a fan. Fan control buttons on the screen enable the aperture of the fans to be modified so that a variable number of children can be visualized in each fan.}, url = {http://www.freepatentsonline.com/6104400.html} } @INPROCEEDINGS{Ham2002, author = {Frank van Ham and Jarke J. van Wijk}, title = {Beamtrees: Compact Visualization of Large Hierarchies}, pages = {93--100}, abstract = {Beamtrees are a new method for the visualization of large hierarchical data sets. Nodes are shown as stacked circular beams, such that both the hierarchical structure as well as the size of nodes are depicted. The dimensions of beams are calculated using a variation of the treemap algorithm. A small user study indicated that beamtrees are significantly more effective than nested treemaps and cushion treemaps for the extraction of global hierarchical information.}, doi = {10.1109/INFVIS.2002.1173153}, year = {2002}, booktitle = {InfoVis'02: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Pak Chung Wong and Keith Andrews}, publisher = {IEEE Computer Society}, isbn = {076951751X} } @INPROCEEDINGS{Hao2007, author = {Jie Hao and Kang Zhang and Mao Lin Huang}, title = {{RELT} -- Visualizing Trees on Mobile Devices}, pages = {344--357}, abstract = {The small screens on increasingly used mobile devices challenge the traditional visualization methods designed for desktops. This paper presents a method called "Radial Edgeless Tree" (RELT) for visualizing trees in a 2-dimensional space. It combines the existing connection tree drawing with the space-filling approach to achieve the efficient display of trees in a small geometrical area, such as the screen that are commonly used in mobile devices. We recursively calculate a set of non-overlapped polygonal nodes that are adjacent in the hierarchical manner. Thus, the display space is fully used for displaying nodes, while the hierarchical relationships among the nodes are presented by the adjacency (or boundary-sharing) of the nodes. It is different from the other traditional connection approaches that use a node-link diagram to present the parent-child relationships which waste the display space. The hierarchy spreads from north-west to south-east in a top-down manner which naturally follows the traditional way of human perception of hierarchies. We discuss the characteristics, advantages and limitations of this new technique and suggestions for future research.}, doi = {10.1007/978-3-540-76414-4_34}, year = {2007}, booktitle = {VISUAL'07: Advances in Visual Information Systems}, editor = {Guoping Qiu and Clement Leung and Xiangyang Xue and Robert Laurini}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540764137}, } @INPROCEEDINGS{Hao2007a, author = {Jie Hao and Kang Zhang}, title = {A Mobile Interface for Hierarchical Information Visualization and Navigation}, abstract = {There is a dramatic increase in the population who use mobile computing devices. Though the hardware becomes more powerful, effective support for information rendering on small screens very much lags behind. To display hierarchical information, researchers have proposed many algorithms for desktop screen visualization. Such algorithms are generally divided into connection and enclosure. Connection approach displays hierarchy with a clear structure but consume display area. Enclosure can maximally utilize the screen space but the layout is essentially implicit. This paper describes a new Radial Edgeless Tree (RELT) for visualizing hierarchical data on palm sized devices. The aim of RELT is to combine the advantages of connection and enclosure approaches. By recursively partitioning the display area, this technique maximizes the space usage. The structural clarity of layout can be reached by arranging location of non-overlapping regions. RELT can be adapted for visualizing structural information for various applications.}, doi = {10.1109/ISCE.2007.4382214}, year = {2007}, booktitle = {ISCE'07: Proceedings of the IEEE International Symposium on Consumer Electronics}, publisher = {IEEE Computer Society}, isbn = {9781424411092} } @INPROCEEDINGS{Hao2009, author = {Jie Hao and Kang Zhang and Chad Allen Gabrysch and Qiaoming Zhu}, title = {Managing Hierarchical Information on Small Screens}, pages = {429--441}, abstract = {This paper presents a visualization methodology called Radial Edgeless Tree (RELT) for visualizing and navigating hierarchical information on mobile interfaces. RELT is characterized by recursive division of a polygonal display area, space-filling, maximum screen space usage, and clarity of the hierarchical structure. It is also general and flexible enough to allow users to customize the root location and stylize the layout. The paper presents the general RELT drawing algorithm that is adaptable and customizable for different applications. We demonstrate the algorithm's application for stock market visualization, and also present an empirical study on an emulated implementation with a currently used cell phone interface in terms of their performances in finding desired information.}, doi = {10.1007/978-3-642-00672-2_38}, year = {2009}, booktitle = {Advances in Data and Web Management: Proceedings of the Joint International Conferences APWeb/WAIM 2009}, editor = {Qing Li and Ling Feng and Jian Pei and Sean X.Wang and Xiaofang Zhou and Qiao-Ming Zhu}, publisher = {Springer}, isbn = {9783642006715}, } @ARTICLE{Hao2010, author = {Jie Hao and Chad Allen Gabrysch and Chunying Zhao and Qiaoming Zhu and Kang Zhang}, title = {Visualizing and Navigating Hierarchical Information on Mobile User Interfaces}, journal = {International Journal of Advanced Intelligence}, year = {2010}, volume = {1}, pages = {81--103}, number = {1}, abstract = {This paper presents a visualization approach called Radial Edgeless Tree (RELT) for visualizing and navigating hierarchical information on small screens. Major advantages of the RELT approach include: elegance recursive division of the display area, space-filling, maximum usage of screen estate, and clarity of the hierarchical structure. It offers the flexibility such that users can customize the hierarchy's root location and stylize the layout. The RELT drawing algorithm is adaptable and customizable for different application domains. We have implemented the RELT interface on the Google Android emulator. The paper presents the Android implementation, and then provides an analytical and empirical comparison of the Android implementation with a traditional cell phone interface in terms of their performances in navigating hierarchical information.}, url = {http://aia-i.com/ijai/sample/vol2/no1/81-103.pdf} } @INPROCEEDINGS{Harel2000, author = {David Harel and Gregory Yashchin}, title = {An algorithm for blob hierarchy layout}, pages = {29--40}, abstract = {We present an algorithm for the aesthetic drawing of basic hierarchical blob structures, of the kind found in higraphs and statecharts and in other diagrams in which hierarchy is depicted as topological inclusion. Our work could also be useful in window system dynamics, and possibly also in things like newspaper layout, etc. Several criteria for aesthetics are formulated, and we discuss their motivation, our methods of implementation and the algorithm's performance.}, doi = {10.1145/345513.345240}, year = {2000}, booktitle = {AVI'00: Proceedings of the Working Conference on Advanced Visual Interfaces}, editor = {Vito Di Ges\'u and Stefano Levialdi and Laura Tarantino}, publisher = {ACM Press}, isbn = {1581132522} } @ARTICLE{Harel2002, author = {David Harel and Gregory Yashchin}, title = {An algorithm for blob hierarchy layout}, journal = {The Visual Computer}, year = {2002}, volume = {18}, pages = {164--185}, number = {3}, abstract = {We present an algorithm for the aesthetic drawing of basic hierarchical blob structures, of the kind found in higraphs and statecharts and in other diagrams in which hierarchy is depicted as topological inclusion. Our work could also be useful in Web page design, window system dynamics, and possibly also newspaper layout, etc. Several criteria for aesthetics are formulated, and we discuss their motivation, our methods of implementation and the algorithm's performance.}, doi = {10.1007/s003710100133} } @INPROCEEDINGS{Hasan2002, author = {Masud Hasan and Md. Saidur Rahman and Takao Nishizeki}, title = {A linear algorithm for compact box-drawings of trees}, booktitle = {CCCG'02: Proceedings of the Canadian Conference on Computational Geometry}, year = {2002}, pages = {154--157}, abstract = {In a box-drawing of a rooted tree, each node is drawn by a rectangular box of prescribed size, no two boxes overlap each other, all boxes corresponding to siblings of the tree have the same x-coordinate at their left sides, and a parent node is drawn at a given distance apart from its first child. A box drawing of a tree is compact if it attains the minimum possible rectangular area enclosing the drawing. We give a linear-time algorithm for finding a compact box-drawing of a tree. A known algorithm does not always find a compact box-drawing and takes time $O(n^2)$ if a tree has n nodes.}, url = {http://www.cccg.ca/proceedings/2002/C94.ps} } @ARTICLE{Hasan2003, author = {Masud Hasan and Md. Saidur Rahman and Takao Nishizeki}, title = {A linear algorithm for compact box-drawings of trees}, journal = {Networks}, year = {2003}, volume = {4}, pages = {160--164}, number = {3}, abstract = {In a box-drawing of a rooted tree, each node is drawn by a rectangular box of prescribed size, no two boxes overlap each other, all boxes corresponding to siblings of the tree have the same x-coordinate at their left sides, and a parent node is drawn at a given distance apart from its first child. A box drawing of a tree is compact if it attains the minimum possible rectangular area enclosing the drawing. We give a linear-time algorithm for finding a compact box-drawing of a tree. A known algorithm does not always find a compact box-drawing and takes time $O(n^2)$ if a tree has n nodes.}, doi = {10.1002/net.10092} } @ARTICLE{Heard2009, author = {Jeff Heard and William Kaufmann and Xiaojun Guan}, title = {A novel method for large tree visualization}, journal = {Bioinformatics}, year = {2009}, volume = {25}, pages = {557--558}, number = {4}, abstract = {Many genomic and proteomic analyses generate as a result a tree of genes or proteins. These trees are often large (containing tens of thousands of nodes and edges), and need a visualization tool to fully display all the information contained in the tree. Clustering analysis can be performed on these trees to obtain clusters of proteins, and we need an efficient way to visualize the clustering results. We present a novel tree visualization tool to help with such analyses.}, doi = {10.1093/bioinformatics/btn656} } @INPROCEEDINGS{Heer2004, author = {Jeffrey Heer and Stuart K. Card}, title = {{DOITrees} Revisited: Scalable, Space-Constrained Visualization of Hierarchical Data}, pages = {421--424}, abstract = {This paper extends previous work on focus+context visualizations of tree-structured data, introducing an efficient, space-constrained, multi-focal tree layout algorithm (TreeBlock) and techniques at both the system and interactive levels for dealing with scale. These contributions are realized in a new version of the Degree-Of-Interest Tree browser, supporting real-time interactive visualization and exploration of data sets containing on the order of a million nodes.}, doi = {10.1145/989863.989941}, year = {2004}, booktitle = {AVI'04: Proceedings of the Working Conference on Advanced Visual Interfaces}, editor = {Maria Francesca Costabile}, publisher = {ACM Press}, isbn = {1581138679} } @PATENT{Heer2009, author = {Jeffrey M. Heer and Stuart K. Card}, title = {Method, apparatus, and program product for visualizing tree structured information}, number = {US 7627599 B2}, year = {2009}, abstract = {Apparatus, methods, and computer program products are disclosed that perform computationally efficient layout of hierarchical data structures.}, url = {http://www.freepatentsonline.com/7627599.html} } @ARTICLE{Heine2011, author = {Christian Heine and Dominic Schneider and Hamish Carr and Gerik Scheuermann}, title = {Drawing Contour Trees in the Plane}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2011}, volume = {17}, pages = {1599--1611}, number = {11}, abstract = {The contour tree compactly describes scalar field topology. From the viewpoint of graph drawing, it is a tree with attributes at vertices and optionally on edges. Standard tree drawing algorithms emphasize structural properties of the tree and neglect the attributes. Applying known techniques to convey this information proves hard and sometimes even impossible. We present several adaptions of popular graph drawing approaches to the problem of contour tree drawing and evaluate them. We identify five aesthetic criteria for drawing contour trees and present a novel algorithm for drawing contour trees in the plane that satisfies four of these criteria. Our implementation is fast and effective for contour tree sizes usually used in interactive systems (around 100 branches) and also produces readable pictures for larger trees, as is shown for a $\sim 800$ branch example.}, doi = {10.1109/TVCG.2010.270} } @INPROCEEDINGS{Herman1999, author = {Ivan Herman and Scott Marshall and Guy Melan\c{c}on and David J. Duke and Maylis Delest and Jean-Philippe Domenger}, title = {Skeletal images as visual cues in graph visualization}, pages = {13--22}, abstract = {The problem of graph layout and drawing is fundamental to many aproaches to the visualization of relational information structures. As the data set grows, the visualization problem is compounded by the need to reconcile the user's need for orientation cues with the danger of information overload. Put simply: How can we limit the number of visual elements on the screen so as not to overwhelm the user yet retain enough information that the user is able to navigate and explore the data set confidently? How can we provide orientational cues so that a user can understand the location of the current viewpoint in a large data set? These are problems inherent not only to graph drawing but information visualization in general. We propose a method which extracts the significant features of a directed acyclic graph as the basis for navigation}, doi = {10.1007/978-3-7091-6803-5_2}, year = {1999}, booktitle = {Data Visualization'99: Proceedings of the Joint Eurographics - IEEE TCVG Symposium on Visualization}, editor = {Eduard Gr\"oller and Helwig L\"offelmann and William Ribarsky}, publisher = {Eurographics Association}, } @INPROCEEDINGS{Herman1999a, author = {Ivan Herman and Guy Melan\c{c}on and Maurice M. de Ruiter and Maylis Delest}, title = {Latour -- A Tree Visualisation System}, pages = {392--399}, abstract = {This paper presents some of the most important features of a tree visualisation system called Latour, developed for the purposes of information visualisation. This system includes a number of interesting and unique characteristics, for example the provision for visual cues based on complexity metrics on graphs, which represent general principles that, in our view, graph based information visualisation systems should generally offer.}, doi = {10.1007/3-540-46648-7_40}, year = {1999}, booktitle = {GD'99: Proceedings of the International Symposium on Graph Drawing}, editor = {Jan Kratochv\'{\i}yl}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3540669043}, } @ARTICLE{Herman2000, author = {Ivan Herman and Guy Melan\c{c}on and M. Scott Marshall}, title = {Graph Visualization and Navigation in Information Visualization: A Survey}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2000}, volume = {6}, pages = {24--43}, number = {1}, abstract = {This is a survey on graph visualization and navigation techniques, as used in information visualization. Graphs appear in numerous applications such as Web browsing, state-transition diagrams, and data structures. The ability to visualize and to navigate in these potentially large, abstract graphs is often a crucial part of an application. Information visualization has specific requirements, which means that this survey approaches the results of traditional graph drawing from a different perspective.}, doi = {10.1109/2945.841119} } @ARTICLE{Heydemann1996, author = {Marie-Claude Heydemann and Dominique Sotteau and Jaroslav Opatrny}, title = {Embeddings of complete binary trees into extended grids with edge-congestion 1}, journal = {Parallel Algorithms and Applications}, year = {1996}, volume = {8}, pages = {333--354}, number = {3-4}, abstract = {Let G and H be two simple, undirected graphs. An embedding of the graph G into the graph H is an injective mapping f from the vertices of G to the vertices of H, together with a mapping which assigns to each edge [u, v] of G a path between f (u) and f (v) in H. The extended grid EM(r, s) is the graph whose vertex set is the set of pairs on nonnegative integers, {(i, j) : 0 <= i < r, 0 <= j < s}, in which there is an edge between vertices (i, j) and (k, l) if and only if |I - k| <= 1 and |j - l| <= 1. In this paper, we give an embedding of any complete binary tree of odd height into its optimal square extended grid. This embedding has edge-congestion 1, dilation 2^(n-2) + 1, and its average dilation is less than 1.12. We also show that an embedding of a complete binary tree of odd height into its optimal grid, which is obtained from the embedding into the optimal extended grid by a simple transformation, has edge-congestion 2, dilation 2^(n-1), and it creates in the grid far fewer edges of congestion 2 than the embedding from Zienicke (1990).}, doi = {10.1080/10637199608915560} } @PATENT{Hida2005, author = {Yozo Hida and John O. Lamping and Ramana B. Rao}, title = {Tree visualization system and method based upon a compressed half-plane model of hyperbolic geometry}, number = {US 6901555 B2}, year = {2005}, abstract = {A node-link structure is displayed within a display area, having a narrow rectangular shape with an edge along one side acting as a horizon of a hyperbolic space half-plane. Lower level node features that share a parent node feature have centers of area positioned on the display in order along a line parallel with the horizon, with sufficiently similar spacings along an axis perpendicular to the horizon from the region around a parent node feature, and with sufficiently similar spacings in a dimension parallel to the horizon from adjacent node features along the line, that the lower level node features sharing the parent node feature are perceptible as a group of related node features. The half-plane model with compression is used for layout of the node-link data, and the hyperbolic layout data is mapped to a Euclidean space for display.}, url = {http://www.freepatentsonline.com/6901555.html} } @INPROCEEDINGS{Hlawatsch2014, author = {Marcel Hlawatsch and Michael Burch and Daniel Weiskopf}, title = {Bubble Hierarchies}, pages = {77--80}, abstract = {We introduce bubble hierarchies as an approach to generating algorithmic art from random hierarchies. The technique is based on repeatedly drawing color-coded circles to illustrate parent--child relationships. The algorithm is simple and produces densely packed structures similar to the concept of Apollonian gaskets. We demonstrate the influence of different parameters on the visual outcome, such as the number of created circles or the color encoding. Our algorithm also supports multiple seeding points and obstacles that can be used to influence the layout of the hierarchy.}, doi = {10.1145/2630099.2630107}, year = {2014}, booktitle = {CAe'14: Proceedings of the Workshop on Computational Aesthetics}, editor = {David Mould}, publisher = {ACM}, isbn = {9781450330190} } @INPROCEEDINGS{Holten2005, author = {Danny Holten and Roel Vliegen and Jarke J. van Wijk}, title = {Visual Realism for the Visualization of Software Metrics}, pages = {27--32}, abstract = {The visualization techniques used in current software visualization frameworks make use of a limited set of graphical elements to highlight relevant aspects of a software system. Typical examples of such elements are text, simple geometric shapes and uniform color fills. Although human visual perception enables rapid processing of additional visual cues like shading and texture, they are not used. We contend that such 2D and 3D computer graphics techniques for achieving visual realism can be used to increase the information throughput of software visualization techniques. Visualization results are presented to show how treemaps, cushions, color, texture, and bump mapping can be used to visualize software metrics of hierarchically organized elements of a software system}, doi = {10.1109/VISSOF.2005.1684299}, year = {2005}, booktitle = {VisSoft'05: Proceedings of the IEEE International Workshop on Visualizing Software for Understanding and Analysis}, editor = {Andrian Marcus and Jonathan I. Maletic and Margaret-Anne Storey and Michele Lanza and St\'ephane Ducasse}, publisher = {IEEE Computer Society}, isbn = {0780395409} } @INPROCEEDINGS{Hong2003, author = {Seok-Hee Hong and Tom Murtagh}, title = {{PolyPlane}: An Implementation of a New Layout Algorithm For Trees In Three Dimensions}, pages = {90--91}, } year = {2003}, booktitle = {InfoVis'03: Poster Compendium of the IEEE Symposium on Information Visualization}, url = {http://conferences.computer.org/infovis/files/compendium2003.pdf} } @ARTICLE{Hong2008, author = {Seok-Hee Hong and Peter Eades}, title = {Drawing Trees Symmetrically in Three Dimensions}, journal = {Algorithmica}, year = {2008}, volume = {36}, pages = {153--178}, number = {2}, abstract = {Symmetric graph drawing enables a clear understanding of the structure of the graph. Previous work on symmetric graph drawing has focused on two dimensions. Symmetry in three dimensions is much richer than that of two dimensions. This is the first paper to extend symmetric graph drawing into three dimensions. More specifically, the paper investigates the problem of drawing trees symmetrically in three dimensions. First, we suggest a model for drawing trees symmetrically in three dimensions. Based on this model, we present a linear time algorithm for finding the maximum number of three-dimensional symmetries in trees. We also present a three-dimensional symmetric drawing algorithm for trees.}, doi = {10.1007/s00453-002-1011-4} } @INPROCEEDINGS{Horn2009, author = {Michael S. Horn and Matthew Tobiasz and Chia Shen}, title = {Visualizing Biodiversity with {Voronoi} Treemaps}, pages = {265--270}, abstract = {Introduced in 2005, the Voronoi treemap algorithm is an information visualization technique for displaying hierarchical data. Voronoi treemaps use weighted, centroidal Voronoi diagrams to create a nested tessellation of convex polygons. However, despite appealing qualities, few real world examples of Voronoi treemaps exist. In this paper, we present a multi-touch tabletop application called Involv that uses the Voronoi treemap algorithm to create an interactive visualization for the Encyclopedia of Life. Involv is the result of a year-long iterative development process and includes over 1.2 million named species organized in a nine-level hierarchy. Working in the domain of life sciences, we have encountered the need to display supplemental hierarchical data to augment information in the treemap. Thus we propose an extension of the Voronoi treemap algorithm that employs force-directed graph drawing techniques both to guide the construction of the treemap and to overlay a supplemental hierarchy.}, doi = {10.1109/ISVD.2009.22}, year = {2009}, booktitle = {ISVD'09: Proceedings of the International Symposium on Voronoi Diagrams}, editor = {Fran\c{c}ois Anton}, publisher = {IEEE Computer Society}, isbn = {9780769537818} } @ARTICLE{Horowitz1981, author = {Ellis Horowitz and Alessandro Zorat}, title = {The Binary Tree as an Interconnection Network: Applications to Multiprocessor Systems and {VLSI}}, journal = {IEEE Transactions on Computers}, year = {1981}, volume = {C-30}, pages = {247--253}, number = {4}, abstract = {The binary tree is a natural way to organize complex computations by a computer. For problems that can be naturally divided into a tree structure, a great deal of parallelism may be employed. In this paper we examine several aspects of the binary tree structure as it relates to both multiprocessor systems and to VISI circuit design. First, we present an algorithm for mapping an arbitrary binary tree onto the plane. An analysis shows the density of this mapping. Second, we consider the problem of routing messages within a binary tree under the assumption that certain nodes may be faulty. Finally, we analyze the binary tree's capacity to transfer information between nodes and we compare it to the capacity of the linear array and the grid.}, doi = {10.1109/TC.1981.1675772} } @INPROCEEDINGS{Huang2007, author = {Mao Lin Huang and Quang Vinh Nguyen and Wei Lai and Xiaodi Huang}, title = {Three-Dimensional {EncCon} Tree}, pages = {429--433}, abstract = {This paper describes a three-dimensional extension of a enclosure+connection layout technique, called EncCon tree. The three-dimensional visualization includes layout and navigation. The layout algorithm directly generalizes the two-dimensional EncCon tree layout algorithm to three-dimensional space in which nodes at the same level of the hierarchy are placed onto the same plane. The interactive navigation uses standard three-dimensional viewing techniques which include view transformation, rotation and zoom.}, doi = {10.1109/CGIV.2007.82}, year = {2007}, booktitle = {CGIV'07: Proceedings of the Computer Graphics, Imaging and Visualisation}, editor = {Ebad Banissi and Muhammad Sarfraz and Natasha Dejdumrong}, publisher = {IEEE Computer Society}, isbn = {0769529283} } @INCOLLECTION{Huang2007a, author = {Mao Lin Huang and Quang Vinh Nguyen and Wei Lai}, title = {Creating Visual Browsers for Large-Scale Online Auctions}, booktitle = {E-Service Intelligence -- Methodologies, Technologies and Applications}, publisher = {Springer}, year = {2007}, editor = {Jie Lu and Da Ruan and Guangquan Zhang}, pages = {579--600}, abstract = {This chapter discusses the requirements raised for running online auctions as well as the technical issues on the design of graphical user interfaces and how we could use these graphical interfaces to help users navigate visualization technique called EncCon as well as the design of graphic attributes that can be used to present the domain specific attributes of the auction items and the relational structures among these items, and these graphic presentations will provide users with a clear map showing the possible paths to the target items. We will demonstrate the effectiveness of our techniques by illustrating an online auction prototype that simulates the ordinary auction activities with the assistance of visualization.}, doi = {10.1007/978-3-540-37017-8_27} } @INPROCEEDINGS{Huang2009, author = {Mao Lin Huang and Tze-Haw Huang and Jiawan Zhang}, title = {{TreemapBar}: Visualizing Additional Dimensions of Data in Bar Chart}, pages = {98--103}, abstract = {Bar chart is a very common and simple graph that is mainly used to visualize simple x, y plots of data for numerical comparisons by partitioning the categorical data values into bars and typically limited to operate on highly aggregated dataset. In today's growing complexity of business data with multi dimensional attributes using bar chart itself is not sufficient to deal with the representation of such business dataset and it also not utilizes the screen space efficiently.Nevertheless, bar chart is still useful because of its shape create strong visual attention to users at first glance than other visualization techniques. In this article, we present a treemap bar chart + tablelens interaction technique that combines the treemap and bar chart visualizations with a tablelens based zooming technique that allows users to view the detail of a particular bar when the density of bars increases. In our approach, the capability of the original bar chart and treemaps for representing complex business data is enhanced and the utilization of display space is also optimized.}, doi = {10.1109/IV.2009.22}, year = {2009}, booktitle = {IV'09: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Liz Stuart and Theodor G. Wyeld and Mikael Jern and Gennady Andrienko and Nasrullah Memon and Reda Alhajj and Remo Aslak Burkhard and Georges Grinstein and Dennis Groth and Anna Ursyn and Jimmy Johansson and Camilla Forsell and Urska Cvek and Marjan Trutschi and Francis T. Marchese and Carsten Maple and Andrew J. Cowell and Andrew Vande Moere}, publisher = {IEEE Computer Society}, isbn = {9780769537337} } @INPROCEEDINGS{Husken2007, author = {Peter H\"usken and J\"urgen Ziegler}, title = {Degree-of-Interest Visualization for Ontology Exploration}, pages = {116--119}, abstract = {In recent years, improvements in semantic web technologies have given us new expressive description languages for modeling knowledge domains — the so called ontologies. Nevertheless, ontology editors lack of easy and intuitive user interfaces, so that the exploration and creation of ontologies is often too difficult to be efficient. In this short paper, we introduce a new tree widget which utilizes sophisticated visualization and interaction features for ontology exploration and editing as a work in progress study. Due to space limitations we co+ncentrate here on the aspect of ontology browsing.}, doi = {10.1007/978-3-540-74796-3_12}, year = {2007}, booktitle = {INTERACT'07: Proceedings of the IFIP TC13 Conference on Human-Computer Interaction, Part II}, editor = {C\'ecilia Baranauskas and Philippe Palanque and Julio Abascal and Simone Diniz Junqueira Barbosa}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540747994}, } @ARTICLE{Irani2006, author = {Pourang Irani and Dean Slonowsky and Peer Shajahan}, title = {Human perception of structure in shaded space-filling visualizations}, journal = {Information Visualization}, year = {2006}, volume = {5}, pages = {47--61}, number = {1}, abstract = {Very early in the object recognition process the human visual system extracts shading information. While shading can enhance the visibility of structures, it can have a negative impact on the judgment of sizes of elements in a structure. In certain visualization systems the underlying hierarchical structure is not noticeably explicit, such as in space-filling techniques. We hypothesize that in such cases, shading can make the structure more explicit. In this paper, we report the results of two experiments designed to investigate the effects of shading information on extracting the structure in space-filling visualizations. In the first experiment subjects performed better with the visualization tool with shading on structure-based tasks. Our results do not show that shading impairs users' judgment on size-based tasks. A subjective evaluation shows that users preferred interacting with the system when shading was available. The second experiment was designed to investigate further users' capacity to identify structural elements within the space-filling visualization. A substructure recognition task was employed in this experiment and results show that users are capable of identifying sub-structures quicker and with fewer errors when the visualization tool was equipped with shading information than without. The results of both experiments provide evidence that shading information can be used to effectively obtain structural information from space-filling visualizations.}, doi = {10.1057/palgrave.ivs.9500113} } @INPROCEEDINGS{Ishihara2006, author = {Masaki Ishihara and Kazuo Misue and Jiro Tanaka}, title = {Ripple Presentation for Tree Structures with Historical Information}, pages = {153--160}, abstract = {We propose a new method for representing tree structures with historical information. We call this method Ripple Presentation. Categories of nodes are represented by the angles of edges and elapsed time is represented by the length of the edges. In this way, the method can express both the time series and categories, which has been diffic lt to achieve with either tree structures or lists. As a result, users can nderstand the overall information from their viewpoint view and discover target information effectively. We applied the method to trackback links of Weblog articles and the latest articles of News sites using RSS on Web as a resource.}, url = {http://portal.acm.org/citation.cfm?id=1151903.1151927}, year = {2006}, booktitle = {APVIS'06: Proceedings of the Asia Pacific Symposium on Information Visualization}, editor = {Kazuo Misue and Kozo Sugiyama and Jiro Tanaka}, publisher = {Australian Computer Society}, series = {Conference in Research and Practice in Information Technology}, isbn = {1920682414} } @TECHREPORT{Itoh2002, author = {Takayuki Itoh and Yasumasa Kajinaga and Yuko Ikehata and Yumi Yamaguchi}, title = {Data Jewelry Box: A Graphics Showcase for Large-Scale Hierarchical Data Visualization}, institution = {IBM Research}, year = {2002}, number = {RT0427}, abstract = {We see many kinds of large-scale hierarchical data in our daily lives, such as file systems of computers, company organizations, and category-based Web search sites such as Yahoo. Most of the GUIs for these data sources first represent a higher level of the data, and provide an interface so that users can select an interesting portion of the data and locally explore the lower levels. On the other hand, there are not many visualization techniques that give an overview of the data by placing all of the lower-level data onto a display region. How can we implement such a technique that represents all the data in one display, just like the showcases of a jewelry store displays all the jewels in the shop? That is the motivation of this research. The report presents a visualization technique that places all of the lowest-level portions of a hierarchical data set on a display space. It first groups icons that denote the lowest-level data, and then generates rectangles that enclose each group of icons. It repeats the process of generating rectangles that enclose the lower-level rectangles, until the highest-level rectangles are enclosed by the largest rectangle. To use the display space most reasonably, our technique efficiently searches for gaps where rectangles can be located without overlapping adjacent rectangles. We use Delaunay triangular meshes that connect the centers of the rectangles to quickly find the gaps.}, url = {http://domino.research.ibm.com/library/cyberdig.nsf/1e4115aea78b6e7c85256b360066f0d4/65ee18867a4cf82385256b870028fa47} } @INPROCEEDINGS{Itoh2003, author = {Takayuki Itoh and Koji Koyamada}, title = {{HeiankyoView}: Orthogonal Representation of Large-scale Hierarchical Data}, booktitle = {PBit'03: Proceedings of the International Symposium Towards Peta-Bit Ultra Networks}, year = {2003}, pages = {125--130}, abstract = {Visualization is very useful for various large-scale computing fields. One of the authors has reported a hierarchical data visualization technique, and applied it to various large-scale computing data including large-scale Web sites, but also for data mining results, Web search queries, network intrusion detection results, and distributed processes. This paper presents the new hierarchical data visualization technique, HeiankyoView, which can be also applied to various large-scale computing fields. It places data items of input data while it packs the items as many as possible in small display areas, and aligns the items along X-axis and Y-axis of the display area. The technique represents nodes of hierarchical data as a set of rectangles, which are parallel to X-axis and Y-axis. Here the technique orthogonally divides the display area by extension lines of edges of previously placed rectangles. By referring the grid-like subspaces of the display area, the technique quickly finds the adequate positions to place remaining rectangles.}, url = {http://itolab.is.ocha.ac.jp/~itot/paper/ItotRICPE18.pdf} } @ARTICLE{Itoh2004, author = {Takayuki Itoh and Yumi Yamaguchi and Yuko Ikehata and Yasumasa Kajinaga}, title = {Hierarchical Data Visualization Using a Fast Rectangle-Packing Algorithm}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2004}, volume = {10}, pages = {302--313}, number = {3}, abstract = {We present a technique for the representation of large-scale hierarchical data which aims to provide good overviews of complete structures and the content of the data in one display space. The technique represents the data by using nested rectangles. It first packs icons or thumbnails of the lowest-level data and then generates rectangular borders that enclose the packed data. It repeats the process of generating rectangles that enclose the lower-level rectangles until the highest-level rectangles are packed. We present two rectangle-packing algorithms for placing items of hierarchical data onto display spaces. The algorithms refer to Delaunay triangular meshes connecting the centers of rectangles to find gaps where rectangles can be placed. The first algorithm places rectangles where they do not overlap each other and where the extension of the layout area is minimal. The second algorithm places rectangles by referring to templates describing the ideal positions for nodes of input data. It places rectangles where they do not overlap each other and where the combination of the layout area and the distances between the positions described in the template and the actual positions is minimal. It can smoothly represent time-varying data by referring to templates that describe previous layout results. It is also suitable for semantics-based or design-based data layout by generating templates according to the semantics or design.}, doi = {10.1109/TVCG.2004.1272729} } @INPROCEEDINGS{Jeong1998, author = {Chang-Sung Jeong and Alex Pang}, title = {Reconfigurable Disc Trees for Visualizing Large Hierarchical Information Space}, pages = {19--25}, abstract = {We present a new visualization technique, called RDT (Reconfigurable Disc Tree) which can alleviate the disadvantages of cone trees significantly for large hierarchies while maintaining its context of using 3D depth. In RDT, each node is associated with a disc around which its children are placed. Using discs instead of cones as the basic shape in RDT has several advantages: significant reduction of occluded region, sharp increase in number of displayed nodes, and easy projection onto plane without visual overlapping. We show that RDT can greatly enhance user perception by transforming its shapes dynamically in several ways:(1) disc tree which can significantly reduce the occluded region by the foreground objects, (2) compact disc tree which can increase the number of nodes displayed on the screen, and (3) plane disc tree which can be mapped onto the plane without visual overlapping. We describe an implementation of our visualization system called VISIT (Visual Information System for reconfigurable dIsc Tree). It provides 2D and 3D layouts for RDT and various user interface features such as tree reconfiguration, tree transformation, tree shading, viewing transformation, animation, selection and browsing which can enhance the user perception and navigation capabilities. We also evaluate our system using the following three metrics: percentage of occlusion, density of displayed nodes on a screen. number of identifiable nodes.}, doi = {10.1109/INFVIS.1998.729555}, year = {1998}, booktitle = {InfoVis'98: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Graham Wills and John Dill}, publisher = {IEEE Computer Society}, isbn = {0818690933} } @TECHREPORT{Jia2008, author = {Yuntao Jia and John C. Hart}, title = {Drawing Trees: How Many Circles to Use?}, institution = {University of Illinois}, year = {2008}, abstract = {In this paper, we proposed a new approach for drawing rooted trees on circles. Previous approaches either draw entire tree on a single circle or draw too many circles that every node and its children are on a new circle. As a result, they only work well on limited kinds of trees. In contrary, our approach adaptively choose how many circles to use based on a single user input and it can be generalized well to all kinds of trees. Our approach has three phases. First, we recursively divide the tree into a hierarchy of subtrees according to the user input. The subtrees are then processed from bottom to top of the hierarchy and each of them is drawn around a separated circle. Finally, layout of subtrees are assembled together to form the layout of the entire tree. Comparing to previous methods, our approach obtains both compact and pleasing tree drawings with less bends. Furthermore, our method naturally supports visualization interactions, such as locally zooming in/out, when user navigates the drawings. Several examples are provided to demonstrate the effectiveness of our approach.}, url = {http://hdl.handle.net/2142/14068} } @INPROCEEDINGS{Jia2009, author = {Ming Jia and Sivakumar Swaminathan and Eve Syrkin Wurtele and Julie Dickerson}, title = {{MetNetGE}: Visualizing Biological Networks in Hierarchical Views and {3D} Tiered Layouts}, pages = {287--294}, abstract = {Linking experimental data with large-scale biomedical networks is key for achieving new discoveries in system biology research. Visualization tools that facilitate these tasks often result in a dense Web of connections that resembles a tangled hairball and is difficult to interpret. MetNetGE is an interactive pathway navigation tool based on Google Earth that features novel visualization techniques for pathway information display. Instead of simply showing all the pathways in a network in a complex graph, MetNetGE visualizes the entire network of pathways based on the hierarchical pathway ontology using a novel radial space filling (RSF) method. Orbits show when pathways belong to multiple categories. Mapping cumulative experiment statistics on the RSF drawing aids biologists in easily identifying highly activated pathways in an experiment. After identifying key pathways, biologists can fly to the corresponding region and see the detailed pathway and experimental data in an aligned 3D tiered layout with simplified cross-layer connection patterns.}, doi = {10.1109/BIBMW.2009.5332109}, year = {2009}, booktitle = {BIBMW'09: Proceedings of the IEEE International Conference on Bioinformatics and Biomedicine Workshops}, editor = {Jake Chen and Xin Chen and John Ely and Dilek Hakkani-Tr and Jing He and Hui-Huang Hsu and Li Liao and Chunmei Liu and Mihai Pop and Shoba Ranganathan and Chandan K. Reddy and Jianhua Ruan and Yinglei Song and Vincent S. Tseng and Lyle Ungar and Di Wu and Zhijun Wu and Kai Xu and Hong Yu and Alexander Zelikovsky}, publisher = {IEEE Computer Society}, isbn = {9781424451210} } @INPROCEEDINGS{Jia2010, author = {Ming Jia and Ling Li and Erin Boggess and Eve Syrkin Wurtele and Julie A. Dickerson}, title = {Visualizing Multivariate Hierarchic Data Using Enhanced Radial Space-Filling Layout}, pages = {350--360}, abstract = {Currently, visualization tools for large ontologies (e.g., pathway and gene ontologies) result in a very flat wide tree that is difficult to fit on a single display. This paper develops the concept of using an enhanced radial space-filling (ERSF) layout to show biological ontologies efficiently. The ERSF technique represents ontology terms as circular regions in 3D. Orbital connections in a third dimension correspond to non-tree edges in the ontology that exist when an ontology term belongs to multiple categories. Biologists can use the ERSF layout to identify highly activated pathway or gene ontology categories by mapping experimental statistics such as coefficient of variation and overrepresentation values onto the visualization. This paper illustrates the use of the ERSF layout to explore pathway and gene ontologies using a gene expression dataset from E. coli.}, doi = {10.1007/978-3-642-17289-2_34}, year = {2010}, booktitle = {Advances in Visual Computing: Proceedings of the International Symposium on Visual Computing 2010}, editor = {George Bebis and Richard Boyle and Bahram Parvin and Darko Koracin and Ronald Chung and Riad Hammoud and Muhammad Hussain and Tan Kar-Han and Roger Crawfis and Daniel Thalmann and David kao and Lisa Avila}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3642172881}, } @ARTICLE{Jia2010a, author = {Ming Jia and Suh-Yeon Choi and Dirk Reiners and Eve S. Wurtele and Julie A. Dickerson}, title = {{MetNetGE}: interactive views of biological networks and ontologies}, journal = {BMC Bioinformatics}, year = {2010}, volume = {11}, number = {469}, abstract = {Linking high-throughput experimental data with biological networks is a key step for understanding complex biological systems. Currently, visualization tools for large metabolic networks often result in a dense web of connections that is difficult to interpret biologically. The MetNetGE application organizes and visualizes biological networks in a meaningful way to improve performance and biological interpretability. MetNetGE is an interactive visualization tool based on the Google Earth platform. MetNetGE features novel visualization techniques for pathway and ontology information display. Instead of simply showing hundreds of pathways in a complex graph, MetNetGE gives an overview of the network using the hierarchical pathway ontology using a novel layout, called the Enhanced Radial Space-Filling (ERSF) approach that allows the network to be summarized compactly. The non-tree edges in the pathway or gene ontology, which represent pathways or genes that belong to multiple categories, are linked using orbital connections in a third dimension. Biologists can easily identify highly activated pathways or gene ontology categories by mapping of summary experiment statistics such as coefficient of variation and overrepresentation values onto the visualization. After identifying such pathways, biologists can focus on the corresponding region to explore detailed pathway structure and experimental data in an aligned 3D tiered layout. In this paper, the use of MetNetGE is illustrated with pathway diagrams and data from E. coli and Arabidopsis. MetNetGE is a visualization tool that organizes biological networks according to a hierarchical ontology structure. The ERSF technique assigns attributes in 3D space, such as color, height, and transparency, to any ontological structure. For hierarchical data, the novel ERSF layout enables the user to identify pathways or categories that are differentially regulated in particular experiments. MetNetGE also displays complex biological pathway in an aligned 3D tiered layout for exploration.}, doi = {10.1186/1471-2105-11-469} } @INPROCEEDINGS{Johnson1991, author = {Brian Johnson and Ben Shneiderman}, title = {{Tree-Maps}: A space-filling approach to the visualization of hierarchical information structures}, pages = {284--291}, abstract = {A method for visualizing hierarchically structured information is described. The tree-map visualization technique makes 100\% use of the available display space, mapping the full hierarchy onto a rectangular region in a space-filling manner. This efficient use of space allows very large hierarchies to be displayed in their entirety and facilitates the presentation of semantic information. Tree-maps can depict both the structure and content of the hierarchy. However, the approach is best suited to hierarchies in which the content of the leaf nodes and the structure of the hierarchy are of primary importance, and the content information associated with internal nodes is largely derived from their children.}, doi = {10.1109/VISUAL.1991.175815}, year = {1991}, booktitle = {Visualization'91: Proceedings of the IEEE Conference on Visualization}, editor = {Gregory M. Nielson and Larry Rosenblum}, publisher = {IEEE Computer Society}, isbn = {0818622458} } @INPROCEEDINGS{Johnson1992, author = {Brian Johnson}, title = {TreeViz: Treemap visualization of hierarchically structured information}, pages = {369--370}, abstract = {TreeViz is an Apple Macintosh implementation of the treemap technique for visualizing hierarchical information structures. TreeViz enables users to visualize and browse large hierarchically structured information spaces. TreeViz enables the drawing of hierarchies an order of magnitude larger (number of nodes) than is possible with typical presentation methods, given the same display space.}, doi = {10.1145/142750.142833}, year = {1992}, booktitle = {CHI'92: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems}, editor = {Penny Bauersfeld and John Bennett and Gene Lynch}, publisher = {ACM Press}, isbn = {0897915135} } @PHDTHESIS{Johnson1993, author = {Brian Scott Johnson}, title = {Treemaps: Visualizing hierarchical and categorical data}, school = {University of Maryland}, year = {1993}, note = {HCIL-94-04, UMI-94-25057}, abstract = {Treemaps are a graphically based method for the visualization of hierarchical or categorical data spaces. Treemap presentations of data shift mental workload from the cognitive to the perceptual systems, taking advantage of the human visual processing system to increase the bandwidth of the human-computer interface. Efficient use of display space allows for the simultaneous presentation of thousands of data records, as well as facilitating the presentation of semantic information. Treemaps let users see the forest and the trees by providing local detail in the context of a global overview, providing a visually engaging environment in which to analyze, search, explore and manipulate large hierarchical and categorical data spaces. The treemap method of hierarchical visualization, at its core, is based on the property of containment. This property of containment is a fundamental idea which powerfully encapsulates many of our reasons for constructing information hierarchies. All members of the treemap family of algorithms partition multi-dimensional display spaces based on weighted hierarchical data sets. In addition to generating treemaps and standard traditional hierarchical diagrams, the treemap algorithms extend non-hierarchical techniques such as bar and pie charts into the domain of hierarchical presentation. Treemap algorithms can be used to generate bar charts, outlines, traditional 2-D node and link diagrams, pie charts, cone trees, cam trees, drum trees, etc. Generating existing diagrams via treemap transformations is an excercise meant to show the power, ease, and generality with which alternative presentations can be generated from the basic treemap algorithms. Controlled experiments with novice treemap users and real data highlight the strengths of treemaps and provide direction for improvement. Experimental results show that treemaps are a powerful visualization tool for large data sets, significantly reducing user performance times for global comparison tasks. Effective visualizations of large data sets can help users gain insight into relevant features of the data, construct accurate mental models of the information, and locate regions of particular interest. Treemaps are based on simple, fundamental ideas, but they are the building blocks with which an entire world of unique and exciting visualizations can be built.}, url = {http://search.proquest.com/docview/304079297/abstract} } @INPROCEEDINGS{Joshi2004, author = {Jyoti Joshi and Brendan Cleary and Chris Exton}, title = {Application of Helix Cone Tree Visualizations to Dynamic Call Graph Illustration}, pages = {68--75}, abstract = {We describe a tool that enables users to record and visualise runtime behaviour of software applications developed in Java. The execution trace, stored in the form of an XML file is visualized using 3D call graphs that are an extension of the Cone Tree information visualisation technique. This tool gives the user the ability to create several call graph views from a program's execution trace, providing additional representations of the program execution to both novice and expert programmers for the purposes of program execution analysis.}, url = {http://www.dcs.warwick.ac.uk/pvw04/p10.pdf}, year = {2004}, booktitle = PROC # {Program Visualization Workshop 2000}, editor = {Ari Korhonen}, publisher = {University of Warwick Research Report CS-RR-407}, isbn = {0902683748}, } @INPROCEEDINGS{Jusufi2012, author = {Ilir Jusufi and Andreas Kerren and Vladyslav Aleksakhin and Falk Schreiber}, title = {Visualization of mappings between the gene ontology and cluster trees}, abstract = {Ontologies and hierarchical clustering are both important tools in biology and medicine to study high-throughput data such as transcriptomics and metabolomics data. Enrichment of ontology terms in the data is used to identify statistically overrepresented ontology terms, giving insight into relevant biological processes or functional modules. Hierarchical clustering is a standard method to analyze and visualize data to find relatively homogeneous clusters of experimental data points. Both methods support the analysis of the same data set, but are usually considered independently. However, often a combined view is desired: visualizing a large data set in the context of an ontology under consideration of a clustering of the data. This paper proposes a new visualization method for this task.}, doi = {10.1117/12.906700}, year = {2012}, booktitle = {VDA'12: Proceedings of the Conference on Visualization and Data Analysis}, editor = {Pak Chung Wong and David L. Kao and Ming C. Hao and Chaomei Chen and Robert Kosara and Mark A. Livingston and Jinah Park and Ian Roberts}, publisher = {SPIE}, isbn = {9780819489418} } @INPROCEEDINGS{Kappe2003, author = {Frank Kappe and Georg Droschl and Wolfgang Kienreich and Vedran Sabol and Jutta Becker and Keith Andrews and Michael Granitzer and Klaus Tochtermann and Peter Auer}, title = {{InfoSky}: Visual Exploration of Large Hierarchical Document Repositories}, pages = {1268--1272}, url = {http://www.worldcat.org/title/human-centred-computing-cognitive-social-and-ergonomic-aspects/oclc/249275186}, year = {2003}, booktitle = {Human-Centered Computing: Cognitive, Social, and Ergonomic Aspects: Proceedings of the HCI International}, editor = {Don Harris and Vincent Duffy and Michael Smith and Constantine Stephanidis}, publisher = {Lawrence Erlbaum Associates}, isbn = {0805849327} } @INPROCEEDINGS{Karstens2003, author = {Bernd Karstens and Matthias Kreuseler and Heidrun Schumann}, title = {Visualization of Complex Structures on Mobile Handhelds}, booktitle = {IMC'03: Proceedings of the International Workshop Mobile Computing}, year = {2003}, abstract = {Information Visualization has become an important research topic in Computer Graphics. One key issue of this topic is the visual presentation of intrinsic structures of complex information spaces. Today nearly all approaches of structure visualization are designed for none-mobile devices such as PCs or workstations. However, mobile handhelds have become more popular in recent years, and are increasingly used in different application domains. Limited resources of these devices require new paradigms for information presentation and interaction such as new methods for structure visualization based on new metaphors for efficient screen space usage. This paper describes how recent techniques of structure visualization can be adapted or redesigned for mobile pocket-sized devices.}, url = {http://vcg.informatik.uni-rostock.de/~schumann/papers/2002+/IMC_2003.pdf} } @PATENT{Keahey2018, author = {Thomas A. Keahey and Daniel J. Rope and Graham J. Wills}, title = {Generating an Outside-in Hierarchical Tree Visualization}, number = {US 20180046690 A1}, year = {2018}, abstract = {A data visualization tool (``tool'') configured to generate a visualization for tree data. The tool can calculate a number of hierarchical levels of the tree data. The tool can further subdivide a presentation area for the data visualization into a number of concentric parts. The concentric parts are equivalent to the number of hierarchical levels. Each of the concentric parts corresponds to one of the hierarchical levels. Further, the tool can graphically generate the data visualization for presentation via an electronic display. A first of the concentric parts that corresponds to a highest of the hierarchal levels is an outermost one of the concentric parts in the presentation area. Each successive concentric part inward corresponds to a next lower hierarchical level.}, url = {http://www.freepatentsonline.com/y2018/0046690.html} } @INPROCEEDINGS{Kerr2003, author = {Bernard Kerr}, title = {Thread Arcs: An email thread visualization}, pages = {211--218}, abstract = {This paper describes Thread Arcs, a novel interactive visualization technique designed to help people use threads found in email. Thread Arcs combine the chronology of messages with the branching tree structure of a conversational thread in a mixed-model visualization by Venolia and Neustaedter (2003) that is stable and compact. By quickly scanning and interacting with Thread Arcs, people can see various attributes of conversations and find relevant messages in them easily. We tested this technique against other visualization techniques with users' own email in a functional prototype email client. Thread Arcs proved an excellent match for the types of threads found in users' email for the qualities users wanted in small-scale visualizations.}, doi = {10.1109/INFVIS.2003.1249028}, year = {2003}, booktitle = {InfoVis'03: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Tamara Munzner and Stephen North}, publisher = {IEEE Computer Society}, isbn = {0780381548} } @INPROCEEDINGS{Keskin1997, author = {Can Keskin and Volker Vogelmann}, title = {Effective Visualization of Hierarchical Graphs With the Cityscape Metaphor}, pages = {52--57}, abstract = {In this paper, we describe an implementation of the cityscape metaphor to visualize trees. The cityscape metaphor is a generalization of barcharts in 3D. Our approach serves for better exploitation of human perception capabilities. To achieve this we employ effective visual cues like node position and size. We determine node positions in terms of perceptual organization. Further we determine node sizes for providing redundant hierarchical information. Redundancy aides in better understanding the tree structure. Finally, we point out some of the advantages of this approach to other spatial metaphors such as cone trees.}, doi = {10.1145/275519.275531}, year = {1997}, booktitle = {NPIVM'97: Proceedings of the Workshop on New Paradigms in Information Visualization and Manipulation}, editor = {David S. Ebert and Charles K. Nicholas}, publisher = {ACM Press}, isbn = {1581130511} } @ARTICLE{Kidd2010, author = {David M. Kidd}, title = {Geophylogenies and the Map of Life}, journal = {Systematic Biology}, year = {2010}, volume = {59}, pages = {741--752}, number = {6}, abstract = {One hundred and fifty years after Charles Darwin wrote his ``Origin of Species'', two major ongoing Web-based scientific projects are collating information on the earth's biological diversity. The Encyclopaedia of Life (EoL) provides a single interface through which information on each being of the same class can be accessed, whereas The Tree of Life (ToL) Web project places these classes onto an evolutionary tree. Here, I propose that a third complementary project should now be considered, the Map of Life (MoL), in which all we know about the biogeographical history of life -- including clades, species, their genes, and the communities they are members of -- is threaded through a dynamic earth history, capturing the spatiotemporal pathways that underlie current and past patterns of biodiversity.}, doi = {10.1093/sysbio/syq043} } @INPROCEEDINGS{Kienreich2003, author = {Wolfgang Kienreich and Vedran Sabol and Michael Granitzer and Frank Kappe and Keith Andrews}, title = {{InfoSky}: A System for Visual Exploration of Very Large, Hierarchically Structured Knowledge Spaces}, abstract = {This publication presents InfoSky, a system enabling exploration of large, hierarchically structured knowledge spaces. InfoSky employs a two-dimensional graphical representation with variable magnification, much like a real-world telescope, to visualise individual documents as stars, hierarchical structures as constellations, and the whole knowledge repository as a galaxy. Force-directed placement is used to position topically similar documents in geometric adjacency, and modified Voronoi diagrams are employed to construct non-overlapping constellation boundaries, while statistical text processing extracts abstracts and keywords from documents and collections. InfoSky combines hierarchy and topical similarity in a visualisation using a striking, well-known metaphor, providing users with a tool appropriate for today’s large, hierarchically structured document repositories.}, url = {http://km.aifb.kit.edu/ws/LLWA/fgwm/Resources/FGWM03_02_Wolfgang_Kienreich.pdf}, year = {2003}, booktitle = {FGWM'03: Proceedings of the Workshop on Knowledge and Experience Management} } @INCOLLECTION{Kim1996, author = {Sung Kwon Kim}, title = {H-v drawings of binary trees}, booktitle = {Software Visualization}, publisher = {World Scientific Publishing}, year = {1996}, editor = {Peter Eades and Kang Zhang}, pages = {101--116}, abstract = {This chapter considers h-v drawings of binary trees and presents new results on it. We prove that binary trees with n nodes can be h-v drawn so that the total edge length is O(n log log n), and so that the maximum edge length is O(SQRT(n log n).}, doi = {10.1142/9789812797995_0006} } @ARTICLE{Kim2007, author = {Namshin Kim and Christopher Lee}, title = {Three-Dimensional Phylogeny Explorer: Distinguishing paralogs, lateral transfer, and violation of ''molecular clock´´ assumption with {3D} visualization}, journal = {BMC Bioinformatics}, year = {2007}, volume = {8}, number = {213}, abstract = {Construction and interpretation of phylogenetic trees has been a major research topic for understanding the evolution of genes. Increases in sequence data and complexity are creating a need for more powerful and insightful tree visualization tools. We have developed 3D Phylogeny Explorer (3DPE), a novel phylogeny tree viewer that maps trees onto three spatial axes (species on the X-axis; paralogs on Z; evolutionary distance on Y), enabling one to distinguish at a glance evolutionary features such as speciation; gene duplication and paralog evolution; lateral gene transfer; and violation of the "molecular clock" assumption. Users can input any tree on the online 3DPE, then rotate, scroll, rescale, and explore it interactively as "live" 3D views. All objects in 3DPE are clickable to display subtrees, connectivity path highlighting, sequence alignments, and gene summary views, and etc. To illustrate the value of this visualization approach for microbial genomes, we also generated 3D phylogeny analyses for all clusters from the public COG database. We constructed tree views using well-established methods and graph algorithms. We used Scientific Python to generate VRML2 3D views viewable in any web browser. 3DPE provides a novel phylogenetic tree projection method into 3D space and its web-based implementation with live 3D features for reconstruction of phylogenetic trees of COG database.}, doi = {10.1186/1471-2105-8-213} } @INPROCEEDINGS{Kim2014, author = {KwangHyuk Kim and JungHyun Han}, title = {Label Embedded Treemapping: A Label Overlap Prevention Technique for {Zoomable Treemaps} and a User Interaction Technique}, pages = {44--53}, abstract = {Data navigation of a treemap -- a widely used tool for visualizing tree data -- becomes more difficult as the amount of data increases. To solve this problem, treemap techniques using zoomable user interface (ZUI) methods -- the most typical of which is the zoomable treemap (ZTM) -- have been proposed. However, ZTMs can incur face text overlapping issues between examined nodes. In order to increase ZTM readability, we propose a label embedded tree map technique that prevents label overlapping and a direct node selection method for the highlighting of focused parent nodes. The proposed tree map technique resolves the ZTM label conflict and the direct node selection method can efficiently improve data navigation.}, doi = {10.1007/978-3-319-07731-4_5}, year = {2014}, booktitle = {Human Interface and the Management of Information. Information and Knowledge Design and Evaluation: Proceedings of the HCI International}, editor = {Sakae Yamamoto}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783319077307} } @INPROCEEDINGS{Kleiberg2001, author = {Ernst Kleiberg and Huub van de Wetering and Jarke J. van Wijk}, title = {Botanical Visualization of Huge Hierarchies}, pages = {87--94}, abstract = {A new method for the visualization of huge hierarchical data structures is presented. The method is based on the observation that we can easily see the branches, leaves, and their arrangement in a botanical tree, despite of the large number of elements. The strand model of Holton is used to convert an abstract tree into a geometric model. Nonleaf nodes are mapped to branches and child nodes to subbranches. A naive application of this model leads to unsatisfactory results, hence it is tailored to suit our purposes better. Continuing branches are emphasized, long branches are contracted, and sets of leaves are shown as fruit. The method is applied to the visualization of directory structures. The elements, directories and files, as well as their relations can easily be extracted, thereby showing that the use of methods from botanical modeling can be effective for information visualization.}, doi = {10.1109/INFVIS.2001.963285}, year = {2001}, booktitle = {InfoVis'01: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Keith Andrews and Steven Roth and Pak Chung Wong}, publisher = {IEEE Computer Society}, isbn = {0769513425} } @ARTICLE{Kleiner1981, author = {Beat Kleiner and John A. Hartigan}, title = {Representing Points in Many Dimensions by Trees and Castles}, journal = {Journal of the American Statistical Association}, year = {1981}, volume = {76}, pages = {260--269}, number = {374}, abstract = {A number of points in k dimensions are displayed by associating with each point a symbol: a drawing of a tree or a castle. All symbols have the same structure derived from a hierarchical clustering algorithm applied to the k variables (dimensions) over all points, but their parts are coded according to the coordinates of each individual point. Trees and castles show general size effects, the change of whole clusters of variables from point to point, trends, and outliers. They are especially appropriate for evaluating the clustering of variables and for observing clusters of points. Their major advantage over earlier attempts to represent multivariate observations (such as profiles, stars, faces, boxes, and Andrews's curves) lies in their matching of relationships between variables to relationships between features of the representing symbol. Several examples are given, including one with 48 variables.}, doi = {10.2307/2287820} } @ARTICLE{Kleiner1981a, author = {Beat Kleiner and John A. Hartigan}, title = {Representing Points in Many Dimensions by Trees and Castles -- Rejoinder}, journal = {Journal of the American Statistical Association}, year = {1981}, volume = {76}, pages = {276}, number = {374}, doi = {10.2307/2287824} } @BOOK{Knuth1968, title = {The Art of Computer Programming}, publisher = {Addison-Wesley}, year = {1968}, author = {Donald Knuth}, volume = {1}, edition = {1st}, isbn = {0201038013}, url = {http://en.wikipedia.org/wiki/The_Art_of_Computer_Programming} } @INPROCEEDINGS{Kobayashi2012, author = {Aimi Kobayashi and Kazuo Misue and Jiro Tanaka}, title = {Edge Equalized Treemaps}, pages = {7--12}, abstract = {Treemap is a visualization method for hierarchical structures in which nodes are drawn as rectangles and arranged in a nested style. Several variations of Treemap have been developed to represent different types of data. In this paper, we propose an Edge Equalized Treemap, a representation that embeds visual data such as a bar chart in leaf rectangles. This representation is characterized by leaf rectangles of equal widths. Because their widths are equal, the scale intervals of charts in a leaf rectangle can be unified, meaning that we can compare charts simply by looking at them. We compare the Edge Equalized Treemap with existing layout methods, and demonstrate the usefulness of our approach.}, doi = {10.1109/IV.2012.12}, year = {2012}, booktitle = {IV'12: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Stefan Bertschi and Camilla Forsell and Jimmy Johansson and Sarah Kenderdine and Francis T. Marchese and Muhammad Sarfraz and Liz Stuart and Anna Ursyn and Theodor G. Wyeld and Hanane Azzag and Mustapha Lebba and Gilles Venturini}, publisher = {IEEE Computer Society}, isbn = {9780769547718} } @INPROCEEDINGS{Koike1993, author = {Hideki Koike and Hirotaka Yoshihara}, title = {Fractal Approaches for Visualizing Huge Hierarchies}, pages = {55--60}, abstract = {This paper describes fractal approaches to the problems which associate with visualizing huge hierarchies. The geometrical characteristic of a fractal, self-similarity, allows users to visually interact with a huge tree in the same manner at every level of the tree. The fractal dimension, a measure of complexity, makes it possible to control the total amount of displayed nodes. A prototype visualization system for UNIX directories is also shown.}, doi = {10.1109/VL.1993.269566}, year = {1993}, booktitle = {VL'93: Proceedings of the IEEE Workshop on Visual Languages}, publisher = {IEEE Computer Society}, isbn = {0818639709} } @ARTICLE{Koike1995, author = {Hideki Koike}, title = {Fractal views: A fractal-based method for controlling information display}, journal = {ACM Transactions on Information Systems}, year = {1995}, volume = {13}, pages = {305--323}, number = {3}, abstract = {Computer users often must view large amounts of information through video displays which are physically limited in size. Although some methods, which automatically display/erase information units based on their degrees of importance, have been proposed, they lack an ability to keep the total amount of displayed information nearly constant. We propose a new method for information display based on fractal theory. By regarding the information structures used in computers as complex objects, we can abstract these objects as well as control their amount. Using our method, (1) the total amount of information is kept nearly constant even when users change their focuses of attention and (2) this amount can be set flexibly. Through mathematical analysis, we show our method's ability to control the amount. An application to program display is also shown. When this method is applied to the display of structured programs, it provides fisheye-like views which integrate local details around the focal point and major landmarks further away.}, doi = {10.1145/203052.203065} } @INPROCEEDINGS{Kratt2011, author = {Julian Kratt and Hendrik Strobelt and Oliver Deussen}, title = {Improving Stability and Compactness in {Street Layout} Visualizations}, pages = {285--292}, abstract = {We present and evaluate improvements for Street Layout, a technique that can be used for visualizing evolving hierarchical data such as file structures or software systems. Street Layouts represent data as street networks, where each street represents a branch of the hierarchy and buildings around streets represent leaves. We extended the initial idea in various ways to increase compactness and visual stability. Our approaches are compared against the current methods in a conducted technical evaluation. A prototypic application shows the applicability of our improvements for visualizing a real world data set.}, doi = {10.2312/PE/VMV/VMV11/285-292}, year = {2011}, booktitle = {VMV'11: Proceedings of the International Workshop on Vision, Modeling and Visualization}, editor = {Peter Eisert and Joachim Hornegger and Konrad Polthier}, publisher = {Eurographics Association}, isbn = {9783905673852} } @INPROCEEDINGS{Kreuseler1999, author = {Matthias Kreuseler and Heidrun Schumann}, title = {Information visualization using a new focus+context technique in combination with dynamic clustering of information space}, pages = {1--5}, abstract = {This paper presents work in progress on our approach to visualizing multi-dimensional and hierarchical information. We propose two new graphical user interfaces, the Magic Eye View (MEV) and ShapeVis to explore information spaces. In order to cope with large information sets we combine MEV and ShapeVis with dynamic hierarchical clustering of information units The Magic Eye View, which implements a new Focus+Context technique, is used as the interface for visualizing those hierarchies. In order to support detailed exploration of the information space (e.g analysis of certain cluster nodes or hierarchy levels) a new technique for visualizing multidimensional information is used. ShapeVis provides 2D or 3D representations of the information objects according to the selected subset of the information space Objects are represented as small closed free-form-surfaces. The location, size and shape of these surfaces describe the original objects in the information space uniquely according to their properties.}, doi = {10.1145/331770.331772}, year = {1999}, booktitle = {NPIV'99: Proceedings of the Workshop on New Paradigms in Information Visualization and Manipulation}, editor = {David S. Ebert and Christopher D. Shaw}, publisher = {ACM Press} } @ARTICLE{Kruskal1983, author = {Joseph B. Kruskal and James M. Landwehr}, title = {Icicle Plot: Better Displays for Hierarchical Clustering}, journal = {The American Statistician}, year = {1983}, volume = {37}, pages = {162--168}, number = {2}, abstract = {An icicle plot is a method for presenting a hierarchical clustering. Compared with other methods of presentation, it is far easier in an icicle plot to read off which objects belong to which clusters, and which objects join or drop out from a cluster as we move up and down the levels of the hierarchy, though these benefits only appear when enough objects are being clustered. Icicle plots are described, and their benefits are illustrated using a clustering of 48 objects.}, doi = {10.2307/2685881} } @INPROCEEDINGS{Kubota2006, author = {Hidekazu Kubota and Toyoaki Nishida and Yasuyuki Sumi}, title = {Visualization of Contents Archive by Contour Map Representation}, pages = {19--32}, abstract = {This article describes a model for sustainable contents management, its visualization algorithms, and the implemented system, called sustainable knowledge globe (SKG). The focal point of our study is visualization using contour maps. The graphical representation of tree-structured contents increases in complexity with the number of contents. The contour map representations can briefly depict the arrangement and structure of contents in an archive. Three contour map representations are proposed assuming the importance of the arrangement design. Nesting, dendroidal, and island-like contours are amplified from the viewpoint of preservation of the structures and arrangements, in addition to supporting shape and texture design. The comparison and applications of the three algorithms are discussed.}, doi = {10.1007/978-3-540-69902-6_3}, year = {2006}, booktitle = {New Frontiers in Artificial Intelligence: Proceedings of the Japanese Society for Artificial Intelligence Conference and Workshops}, editor = {Takashi Washio and Ken Satoh and Hideaki Takeda and Akihiro Inokuchi}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540699019}, } @INPROCEEDINGS{Kwon2012, author = {Oh-hyun Kwon and Junghong Choi and Kyunwon Lee}, title = {Interaction Techniques for a {Strata Treemap}}, booktitle = {Poster session at LDAV'12: IEEE Symposium on Large-Scale Data Analysis and Visualization}, year = {2012}, abstract = {The Strata treemap is a new approach to hierarchy visualization that improves hierarchical structure visibility without distorting node sizes or missing nodes. In this paper, we present useful interaction techniques and visual cues that fit the Strata treemap.}, url = {http://idlab.ajou.ac.kr/stratatreemap/publications/Interaction_Techniques_for_a_Strata_treemap_LDAV2012_Abstract.pdf} } @INPROCEEDINGS{Lai2015, author = {Yen-Jung Lai and Po-Hsun Cheng and Ling-Wei Lu and Chi-Run Rau}, title = {A visualization by Innovated Squarified Treemap for somatosensory data analysis}, pages = {587-588}, abstract = {Enormous information in the Internet, especially in the health care field, makes users cannot get the information they want in time. To let medical staffs, even patients and users, absorb and understand information quickly, data visualization converts information to graphic style. However, some treemap algorithms are not suitable for displaying on certain conditions. This study proposes an improved algorithm, Innovated Squarified Treemap (iS qT), to process the information by data visualization. A comparison shows that our iS qT algorithm provides better performance than original Squarified Treemap algorithm. We expect this paper to facilitate the information be read easier by our iS qT approach in the rehabilitation field.}, doi = {10.1109/GCCE.2015.7398719}, year = {2015}, booktitle = {GCCE'15: Proceedings of the IEEE Global Conference on Consumer Electronics}, publisher = {IEEE Computer Society} } @ARTICLE{Lam2012, author = {Ho-Ching Lam and Ivo D. Dinov}, title = {{Hyperbolic Wheel}: A Novel Hyperbolic Space Graph Viewer for Hierarchical Information Content}, journal = {ISRN Computer Graphics}, year = {2012}, volume = {2012}, abstract = {Tree and graph structures have been widely used to present hierarchical and linked data. Hyperbolic trees are special types of graphs composed of nodes (points or vertices) and edges (connecting lines), which are visualized on a non-Euclidean space. In traditional Euclidean space graph visualization, distances between nodes are measured by straight lines. Displays of large graphs in Euclidean spaces may not utilize efficiently the available space and may impose limitations on the number of graph nodes. The special hyperbolic space rendering of tree-graphs enables adaptive and efficient use of the available space and facilitates the display of large hierarchical structures. In this paper we report on a newly developed advanced hyperbolic graph viewer, Hyperbolic Wheel, which enables the navigation, traversal, discovery and interactive manipulation of information stored in large hierarchical structures. Examples of such structures include personnel records, disc directory structures, ontological constructs, web-pages and other nested partitions. The Hyperbolic Wheel framework provides an intuitive and dynamic graphical interface to explore and retrieve information about individual nodes (data objects) and their relationships (data associations). The Hyperbolic Wheel is freely available online for educational and research purposes.}, doi = {10.5402/2012/609234} } @INPROCEEDINGS{Lamping1995, author = {John Lamping and Ramana Rao and Peter Pirolli}, title = {A focus+context technique based on hyperbolic geometry for visualizing large hierarchies}, pages = {401--408}, abstract = {We present a new focus+context (fisheye) technique for visualizing and manipulating large hierarchies. Our technique assigns more display space to a portion of the hierarchy while still embedding it in the context of the entire hierarchy. The essence of this scheme is to lay out the hierarchy in a uniform way on a hyperbolic plane and map this plane onto a circular display region. This supports a smooth blending between focus and context, as well as continuous redirection of the focus. We have developed effective procedures for manipulating the focus using pointer clicks as well as interactive dragging, and for smoothly animating transitions across such manipulation. A laboratory experiment comparing the hyperbolic browser with a conventional hierarchy browser was conducted.}, doi = {10.1145/223904.223956}, year = {1995}, booktitle = {CHI'95: Proceedings of the SIGCHI Conference on Human Factors in Computing Systems}, editor = {Katz, Irvin R. and Mack, Robert and Marks, Linn and Rosson, Mary Beth and Nielsen, Jakob}, publisher = {ACM Press/Addison-Wesley Publishing Co.}, isbn = {0201847051} } @ARTICLE{Lamping1996, author = {Jonh Lamping and Ramana Rao}, title = {The {Hyperbolic Browser}: A Focus+Context Technique for Visualizing Large Hierarchies}, journal = {Journal of Visual Languages and Computing}, year = {1996}, volume = {7}, pages = {33--55}, number = {1}, abstract = {We present a new focus+context technique based on hyperbolic geometry for visualizing and manipulating large hierarchies. Our technique assigns more display space to a portion of the hierarchy while still embedding it in the context of the entire hierarchy. We lay out the hierarchy in a uniform way on a hyperbolic plane and map this plane onto a display region. The chosen mapping provides a fisheye distortion that supports a smooth blending of focus and context. We have deveoped effective procedures for manipulating the focus using pointer clicks as well as interactive dragging and for smoothly animating transitions across such manipulation. Enhancements to the core mechanisms provide support for multiple foci, control of the tradeoff between node density and node display space, and for visualizing graphs by transforming them into trees.}, doi = {10.1006/jvlc.1996.0003} } @INPROCEEDINGS{Lamping1996a, author = {John Lamping and Ramana Rao}, title = {Visualizing large trees using the hyperbolic browser}, pages = {388--389}, abstract = {We demonstrate a focus+context (fisheye) scheme for visualizing and manipulating large hierarchies. Our approach is to lay out the hierarchy uniformly on the hyperbolic plane and map this plane onto a circular display region. The projection onto the disk provides a natural mechanism for assigning more space to a portion of the hierarchy while still embedding it in a much larger context. Change of focus is accomplished by translating the structure on the hyperbolic plane, which allows a smooth transition without compromising the presentation of the context.}, doi = {10.1145/257089.257389}, year = {1996}, booktitle = {CHI'96: Conference companion of the SIGCHI conference on Human Factors in Computing Systems}, editor = {Michael J. Tauber}, publisher = {ACM Press}, isbn = {0897918320} } @PATENT{Lamping1996b, author = {John O. Lamping and Ramana B. Rao}, title = {Layout of node-link structures in space with negative curvature}, number = {US 5590250}, year = {1996}, abstract = {Layout data indicate positions in a negatively curved layout space for nodes in a hierarchical branch of a node-link structure. The layout data indicate a parent position for parent nodes and, for children that share a parent node, child positions approximately along a circle in the layout space with the parent position approximately at the circle's center. Adjacent child positions are separated by approximately a base spacing. The radii of circles within the branch together approximate a function that increases slowly with number of child nodes such that the radii and spacings along circles are all approximately uniform within the branch. The layout data can be obtained from data defining the node-link structure. The layout data can be used to perform mappings, each obtaining positions for a subset of the nodes. The layout data can be used to present a first representation of the node-link structure on a display. In response to a user signal indicating a change from a first display position near a first feature to a second display position, a second representation can be presented that is perceptible as a changed continuation of the first. The second representation includes, near the second display position, a second feature representing the same part of the node-link structure as the first feature. The second representation can be obtained by a transformation of the layout space, which can be a discrete approximation of a hyperbolic plane.}, url = {http://www.freepatentsonline.com/5590250.html} } @PATENT{Lamping1997, author = {John O. Lamping and Ramana B. Rao}, title = {Displaying node-link structure with region of greater spacings and peripheral branches}, number = {US 5619632}, year = {1997}, abstract = {Node-link data defining a node-link structure are used to present a sequence of representations on a display. The last representation in the sequence is perceptible as a changed continuation of the first. Each representation includes bounded node features, each with a center of area and a nearest node spacing that define a mid-spacing circle. All mid-spacing circles together determine an outer convex hull enclosing a total area for the representation. The mid-spacing circles of a subset of more spaced node features determine an inner convex hull enclosing approximately half the total area and enclosing a region in which nearest node spacings are in general perceptibly greater than in another region outside the second convex hull. The node features also represent a peripheral branch with lower level nodes that are not represented by more spaced node features. In the peripheral branch, node features that share a parent have centers of area positioned approximately along an arc with sufficiently similar spacings from the center of area of the parent node feature and from adjacent node features that they are perceptible as a group of related node features. The inner convex hulls of the first and last representations include subsets of node features representing different sets of nodes. The sequence can produce a perception that one node feature's nearest node spacing increases while another's decreases. The representations can be presented by a series of iterations, and can be presented at animation speeds to produce a perception of continuously moving node features.}, url = {http://www.freepatentsonline.com/5619632.html} } @INPROCEEDINGS{Langelier2005, author = {Guillaume Langelier and Houari Sahraoui and Pierre Poulin}, title = {Visualization-based analysis of quality for large-scale software systems}, pages = {214--223}, abstract = {We propose an approach for complex software analysis based on visualization. Our work is motivated by the fact that in spite of years of research and practice, software development and maintenance are still time and resource consuming, and high-risk activities. The most important reason in our opinion is the complexity of many phenomena related to software, such as its evolution and its reliability. In fact, there is very little theory explaining them. Today, we have a unique opportunity to empirically study these phenomena, thanks to large sets of software data available through open-source programs and open repositories. Automatic analysis techniques, such as statistics and machine learning, are usually limited when studying phenomena with unknown or poorly-understood influence factors. We claim that hybrid techniques that combine automatic analysis with human expertise through visualization are excellent alternatives to them. In this paper, we propose a visualization framework that supports quality analysis of large-scale software systems. We circumvent the problem of size by exploiting perception capabilities of the human visual system.}, doi = {10.1145/1101908.1101941}, year = {2005}, booktitle = {ASE'05: Proceedings of the IEEE/ACM international Conference on Automated Software Engineering}, editor = {Tom Ellman and Andrea Zisman}, publisher = {ACM Press}, isbn = {1581139934} } @INPROCEEDINGS{Langelier2007, author = {Guillaume Langelier and Karim Dhambri}, title = {Visual analysis of {Azureus} using {VERSO}}, pages = {163--164}, abstract = {In this challenge report, we will see how to use VERSO in order to analyse Azureus. We answer the challenge through two separate main goals which represent two possible tasks available in VERSO. The first task is design anomaly detection and the second task is evolution analysis.}, doi = {10.1109/VISSOF.2007.4290720}, year = {2007}, booktitle = {VisSoft'07: Proceedings of the IEEE International Workshop on Visualizing Software for Understanding and Analysis}, editor = {Jonathan I. Maletic and Alexandru Telea and Andrian Marcus}, publisher = {IEEE Computer Society}, isbn = {1424406005} } @INPROCEEDINGS{Larrea2007, author = {Martin L. Larrea and Sergio R. Martig and Silvia M. Castro}, title = {Spherical Layout for {3D} Tree Visualization}, pages = {91--98}, abstract = {The 3D tree visualization faces multiples challenges: the election of an appropriate layout, the use of the interactions that make it easier the data exploration and a metaphor that helps the information understanding. A good combination of these three elements (layout, interactions and metaphor) will result in a visualization that effectively convey the key features of a complex structure or system to a wide range of users and permits the analytical reasoning process. The goal of this work was centered in the 3D tree visualization. In spite of their apparent simplicity, the displaying of a tree in 3D can also introduce new problems that can be overcome with the appropriate interactions. So, we have developed a new visualization technique for 3D tree visualization; this includes the design of a new tree layout that we called Spherical layout and the set of interactions that can be applied on this representation. This technique allows representing hierarchical structures to different levels of detail and also can be used as a visualization technique that allows a tree with attribute to be visualized. The Spherical layout has shown good result for large trees without compromising the performance; this is a key issue in tree visualization.}, url = {http://www.iadis.net/dl/Search_list_open.asp?code=3649}, year = {2007}, booktitle = {IHCI'07: Proceedings of the IADIS International Conference on Interfaces and Human Computer Interaction}, editor = {Antonio Palma dos Reis and Katherine Blashki and Yingcai Xiao}, publisher = {IADIS Press}, isbn = {9789728924393} } @ARTICLE{Larrea2009, author = {Martin Larrea and Dana Urribarri and Sergio Martig and Silvia Castro}, title = {Spherical Layout Implementation using Centroidal Voronoi Tessellations}, journal = {Journal of Computing}, year = {2009}, volume = {1}, pages = {81--86}, number = {1}, abstract = {The 3D tree visualization faces multiple challenges: the election of an appropriate layout, the use of the interactions that make the data exploration easier and a metaphor that helps in the process of information understanding. A good combination of these elements will result in a visualization that effectively conveys the key features of a complex structure or system to a wide range of users and permits the analytical reasoning process. In previous works we presented the Spherical Layout, a technique for 3D tree visualization that provides an excellent base to achieve those key features. The layout was implemented using the TriSphere algorithm, a method that discretized the spheres's surfaces with triangles to achieve a uniform distribution of the nodes. The goal of this work was centered in a new algorithm for the implementation of the Spherical layout; we called it the Weighted Spherical Centroidal Voronoi Tessellations (WSCVT). In this paper we present a detailed description of this new implementation and a comparison with the TriSphere algorithm.}, url = {http://arxiv.org/abs/0912.3974} } @INPROCEEDINGS{Larrea2009a, author = {Martin Larrea and Dana Urribarri and Sergio Martig and Silvia Castro}, title = {User Experience with {Spherical Layout}}, pages = {272--276}, abstract = {The 3D tree visualization faces multiples challenges: the selection of an appropriate layout and the use of proper interactions will help the information understanding. A good combination of these two elements (layout + interactions) will result in a visualization that effectively conveys the key features of a complex structure or system to a wide range of users and permits the analytical reasoning process. In previous work we have presented the Spherical layout; this layout allows the representation of larger information sets, at different levels of detail in a 3D environment. The goal of this work was centered in a user experience for this layout. We developed a file browser application based on the Spherical layout, called Brows.AR, and compared it with Windows File Browser. The results of this experience are shown in this paper.}, url = {http://www.iadis.net/dl/Search_list_open.asp?code=6147}, year = {2009}, booktitle = {CGVCVIP'09: Proceedings of the International Conference on Computer Graphics, Visualization, Computer Vision and Image Processing}, editor = {Yingcai Xiao and Tomaz Amon and Piet Kommers}, publisher = {IADIS}, isbn = {9789728924843} } @PATENT{Leah2008, author = {Robert Leah and Kenneth Parzygnat and Robert Uthe}, title = {Intelligent positioning of items in a tree map visualization}, number = {US 7429987 (B2)}, year = {2008}, abstract = {Displaying data from a data set in a tree map visualization is provided by prioritizing the data in the data set so as to associate a priority with respective elements of the data in the data set. A tree map visualization is generated based on the data set where a location of bounding boxes in the tree map is based on the priority associated with the corresponding element. Tree maps having locations of bounding boxes that are based on a priority associated with the bounding boxes are also provided.}, url = {http://www.freepatentsonline.com/7429987.html} } @MISC{Leclair2010, author = {Andrew LeClair}, title = {Directory Tree, A data visualization mashup}, url = {hhttp://www.andrewleclair.com/archive.html}, year = {2010}, note = {retrieved 09-JAN-2012} } @TECHREPORT{Lee2008, author = {Bongshin Lee and Lev Nachmanson and George G. Robertson and Jonathan Carlson and David Heckerman}, title = {Det. ({Distance Encoded Tree}): A Scalable Visualization Tool for Mapping Multiple Traits to Large Evolutionary Trees}, institution = {Microsoft Research}, year = {2008}, number = {MSR-TR-2008-97}, abstract = {Evolutionary biologists are often interested in finding correlations among biological traits (or attributes) across a number of species, as such correlations may lead to testable hypotheses about the underlying function. Because some species are more closely related than others, computing and visualizing these correlations must be done in the context of the evolutionary tree that relates the species. Although dozens of visualizations for correlated traits have been developed over the decades, the recent explosive growth in the number of traits and species has created a need for a visualization that can scale to dozens of traits mapped to thousands of species and their evolutionary tree to allow the interactive exploration of complex interactions. In this paper, we introduce Det., called detective, an evolutionary tree visualization that allows biologists to see multiple attributes of leaf nodes. We describe a new tree layout algorithm to represent different branch lengths and several visualization and intereaction techniques to address user requirements. We also report informal feedbacks we collected from evolutionary biologists.}, url = {http://research.microsoft.com/apps/pubs/default.aspx?id=70606} } @ARTICLE{Lee2009, author = {Bongshin Lee and Lev Nachmanson and George Robertson and Jonathan M. Carlson and David Heckerman}, title = {{PhyloDet}: A scalable visualization tool for mapping multiple traits to large evolutionary trees}, journal = {Bioinformatics}, year = {2009}, volume = {25}, pages = {2611--2612}, number = {19}, abstract = {Evolutionary biologists are often interested in finding correlations among biological traits across a number of species, as such correlations may lead to testable hypotheses about the underlying function. Because some species are more closely related than others, computing and visualizing these correlations must be done in the context of the evolutionary tree that relates species. In this note, we introduce PhyloDet (short for PhyloDetective), an evolutionary tree visualization tool that enables biologists to visualize multiple traits mapped to the tree.}, doi = {10.1093/bioinformatics/btp454} } @PATENT{Lee2009a, author = {Bongshin Lee and Lev Nachmanson and George G. Robertson}, title = {Visualizing tree structure with different edge lengths}, number = {US 2009/0198725 A1}, year = {2009}, abstract = {A system described herein includes a receiver component that receives multiple data elements, wherein each of the data elements has a common attribute, and wherein the several data elements are hierarchically related. The system may further include an assignor component that independently assigns each of the multiple data elements to one of a plurality of layers, wherein a data element is assigned to a layer based at least in part upon a value of the common attribute that corresponds to the data element. The system may also include a renderer component that receives assignments made by the assignor component and graphically renders a tree structure based at least in part upon the assignments. Furthermore, a color bar can be generated that includes one or more rows based at least in part upon content of the tree structure.}, url = {http://www.freepatentsonline.com/y2009/0198725.html} } @INPROCEEDINGS{Liang2012, author = {Jie Liang and Quang Vinh Nguyen and Simeon Simoff and Mao Lin Huang}, title = {Angular Treemaps -- A New Technique for Visualizing and Emphasizing Hierarchical Structures}, pages = {74--80}, abstract = {Space-filling visualization techniques have proved their capability in visualizing large hierarchical structured data. However, most existing techniques restrict their partitioning process in vertical and horizontal direction only, which cause problem with identifying hierarchical structures. This paper presents a new space-filling method named Angular Treemaps that relax the constraint of the rectangular subdivision. The approach of Angular Treemaps utilizes divide and conquer paradigm to visualize and emphasize large hierarchical structures within a compact and limited display area with better interpretability. Angular Treemaps generate various layouts to highlight hierarchical sub-structure based on user's preferences or system recommendations. It offers flexibility to be adopted into a wider range of applications, regarding different enclosing shapes. Preliminary usability results suggest user's performance by using this technique is improved in locating and identifying categorized analysis tasks.}, doi = {10.1109/IV.2012.23}, year = {2012}, booktitle = {IV'12: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Stefan Bertschi and Camilla Forsell and Jimmy Johansson and Sarah Kenderdine and Francis T. Marchese and Muhammad Sarfraz and Liz Stuart and Anna Ursyn and Theodor G. Wyeld and Hanane Azzag and Mustapha Lebba and Gilles Venturini}, publisher = {IEEE Computer Society}, isbn = {9780769547718} } @INPROCEEDINGS{Liang2013, author = {Jie Liang and Simeon Simoff and Quang Vinh Nguyen and Mao Lin Huang}, title = {Visualizing large trees with divide \& conquer partition}, pages = {79--87}, abstract = {While prior works on enclosure approach, guarantees the space utilization of a single geometrical area, mostly rectangle, this paper proposes a flexible enclosure tree layout method for partitioning various polygonal shapes that break through the limitation of rectangular constraint. Similar to Treemap techniques, it uses enclosure to divide display space into smaller areas for its sub-hierarchies. The algorithm can partition a polygonal shape or even an arbitrary shape into smaller polygons, rotated rectangles or vertical-horizontal rectangles. The proposed method and implementation algorithms provide an effective interactive visualization tool for partitioning large hierarchical structures within a confined display area with different shapes for real-time applications. We demonstrated the effective of the new method with a case study, an automated evaluation and a usability study.}, doi = {10.1145/2493102.2493112}, year = {2013}, booktitle = {VINCI'13: Proceedings of the International Symposium on Visual Information Communication and Interaction}, publisher = {ACM Press}, isbn = {9781450319881} } @ARTICLE{Liang2015, author = {Jie Liang and Quang Vinh Nguyen and Simeon Simoff and Mao Lin Huang}, title = {Divide and Conquer Treemaps: Visualizing large trees with various shapes}, journal = {Journal of Visual Languages and Computing}, year = {2015}, volume = {31}, pages = {104--127}, number = {Part A}, abstract = {Most existing treemaps achieve the space utilization of a single geometrical area, mostly rectangle. Limiting visualization to rectangles could block the human capability on graph recognition, including orientation, shape and differentiation etc. To relax rectangular constraint, we propose a flexible enclosure approach with three algorithms. It partitions large hierarchical structures within a confined display area with different shapes for real-time applications. Our approach is based on the combination of Divide-and-Conquer method and the treemap paradigm. The partitioning algorithms generate three types of layouts with polygonal, angular and rectangular titling, which are flexible to be used separately or combined. We present technical details including the visualization results in the experiments and in the cases studies with real data sets. We evaluated the visualization based on graph drawing aesthetics and optimization criteria. Our usability study shows that (1) treemaps with layout variability support utilization of human capability in graph perception and (2) treemaps adopted in different shaped containers could have a positive impact on user satisfaction and awareness during visual data exploration.}, doi = {10.1016/j.jvlc.2015.10.009} } @INPROCEEDINGS{Liggesmeyer2009, author = {Peter Liggesmeyer and Jens Heidrich and J\"urgen M\"unch and Robert Kalckl\"osch and Henning Barthel and Dirk Zeckzer}, title = {Visualization of Software and Systems as Support Mechanism for Integrated Software Project Control}, pages = {846--855}, abstract = {Many software development organizations still lack support for obtaining intellectual control over their software development processes and for determining the performance of their processes and the quality of the produced products. Systematic support for detecting and reacting to critical process and product states in order to achieve planned goals is usually missing. One means to institutionalize measurement on the basis of explicit models is the development and establishment of a so-called Software Project Control Center (SPCC) for systematic quality assurance and management support. An SPCC is comparable to a control room, which is a well known term in the mechanical production domain. One crucial task of an SPCC is the systematic visualization of measurement data in order to provide context-, purpose-, and role-oriented information for all stakeholders (e.g., project managers, quality assurance managers, developers) during the execution of a software development project. The article will present an overview of SPCC concepts, a concrete instantiation that supports goal-oriented data visualization, as well as examples and experiences from practical applications.}, doi = {10.1007/978-3-642-02574-7_94}, year = {2009}, booktitle = {Human-Computer Interaction. Novel Interaction Methods and Techniques: Proceedings of the HCI International}, editor = {Julie A. Jacko}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642025761}, } @INPROCEEDINGS{Limberger2017, author = {Daniel Limberger and Willy Scheibel and Matthias Trapp and J\"urgen D\"ollner}, title = {Mixed-Projection Treemaps: A novel approach mixing {2D} and {2.5D} Treemaps}, pages = {164--169}, abstract = {This paper presents a novel technique for combining 2D and 2.5D treemaps using multi-perspective views to leverage the advantages of both treemap types. It enables a new form of overview+detail visualization for tree-structured data and contributes new concepts for real-time rendering of and interaction with treemaps. The technique operates by tilting the graphical elements representing inner nodes using affine transformations and animated state transitions. We explain how to mix orthogonal and perspective projections within a single treemap. Finally, we show application examples that benefit from the reduced interaction overhead.}, doi = {10.1109/iV.2017.67}, year = {2017}, booktitle = {IV'17: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Mark W. McK. Bannatyne and Fatma Bouali and Nuno Miguel Soares Datia and Georges Grinstein and Dennis Groth and Weidong Huang and Malinka Ivanova and Sarah Kenderdine and Minoru Nakayama and Joao Moura Pires and Muhammad Sarfraz and Marco Temperini and Anna Ursyn and Gilles Venturini and Theodor G. Wyeld and Jian J. Zhang}, publisher = {IEEE Computer Society}, isbn = {9781538608326} } @INPROCEEDINGS{Lin1999, author = {Y.-B. Lin and Zevi Miller and Manley Perkel and Dan Pritikin and Ivan Hal Sudborough}, title = {On mapping complete binary trees into grids and extended grids}, pages = {242--247}, abstract = {We consider one-to-one, congestion one layouts of complete binary trees into 2-D grids and extended 2-D grids. For such a layout of the complete binary tree $T_h$ of height h into the square $n\times n$ grid we consider the layout's expansion ratio r=n*n/(2^(h+1) -1). For r the least expansion among layouts of $T_h$ into grids, we obtain the bounds 1.122<=r<=1.4656 for large h and n. For layouts into extended grids we similarly obtain bounds 1.03<=r<=1.115. The upper bounds are improvements on previous work, while the lower bounds are the first such to appear.}, doi = {10.1109/ISPAN.1999.778946}, year = {1999}, booktitle = {I-SPAN'99: Proceedings of the International Symposium on Parallel Architectures, Algorithms, and Networks}, editor = {Albert Y. Zomaya and D. Frank Hsu and Oscar Ibarra and Susumu Horiguchi and David Nassimi and Michael Palis}, publisher = {IEEE Computer Society}, isbn = {0769502318} } @ARTICLE{Lin2003, author = {Y.-B. Lin and Zevi Miller and Manley Perkel and Dan Pritikin and Ivan Hal Sudborough}, title = {Expansion of layouts of complete binary trees into grids}, journal = {Discrete Applied Mathematics}, year = {2003}, volume = {131}, pages = {611--642}, number = {3}, abstract = {Let $T_h$ be the complete binary tree of height h. Let M be the infinite grid graph with vertex set Z^2, where two vertices (x1,y1) and (x2,y2) of M are adjacent if and only if |x1-x2|+|y1-y2|=1. Suppose that T is a tree which is a subdivision of $T_h$ and is also isomorphic to a subgraph of M. Motivated by issues in optimal VLSI design, we show that the point expansion ratio $n(T)/n(T_h)=n(T)/(2^(h+1)-1)$ is bounded below by 1.122 for h sufficiently large. That is, we give bounds on how many vertices of degree 2 must be inserted along the edges of $T_h$ in order that the resulting tree can be laid out in the grid. Concerning the constructive end of VLSI design, suppose that T is a tree which is a subdivision of $T_h$ and is also isomorphic to a subgraph of the $n\times n$ grid graph. Define the expansion ratio of such a layout to be $n*n/n(T_h)=n*n/(2^(h+1)-1)$. We show constructively that the minimum possible expansion ratio over all layouts of $T_h$ is bounded above by 1.4656 for sufficiently large h. That is, we give efficient layouts of complete binary trees into square grids, making improvements upon the previous work of others. We also give bounds for the point expansion and expansion problems for layouts of Th into extended grids, i.e. grids with added diagonals.}, doi = {10.1016/S0166-218X(02)00550-4} } @INPROCEEDINGS{Lin2005, author = {Chun-Cheng Lin and Hsu-Chun Yen}, title = {On Balloon Drawings of Rooted Trees}, pages = {285--296}, abstract = {Among various styles of tree drawing, balloon drawing, where each subtree is enclosed in a circle, enjoys a desirable feature of displaying tree structures in a rather balanced fashion. We first design an efficient algorithm to optimize angular resolution and aspect ratio for the balloon drawing of rooted unordered trees. For the case of ordered trees for which the center of the enclosing circle of a subtree need not coincide with the root of the subtree, flipping the drawing of a subtree (along the axis from the parent to the root of the subtree) might change both the aspect ratio and the angular resolution of the drawing. We show that optimizing the angular resolution as well as the aspect ratio with respect to this type of rooted ordered trees is reducible to the perfect matching problem for bipartite graphs, which is solvable in polynomial time. Aside from studying balloon drawing from an algorithmic viewpoint, we also propose a local magnetic spring model for producing dynamic balloon drawings with applications to the drawings of galaxy systems, H-trees, and sparse graphs, which are of practical interest.}, doi = {10.1007/11618058_26}, year = {2005}, booktitle = {GD'05: Proceedings of the International Symposium on Graph Drawing}, editor = {Patrick Healy and Nikola S. Nikolov}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540314257}, } @ARTICLE{Lin2007, author = {Chun-Cheng Lin and Hsu-Chun Yen}, title = {On Balloon Drawings of Rooted Trees}, journal = {Journal of Graph Algorithms and Applications}, year = {2007}, volume = {11}, pages = {431--452}, number = {2}, abstract = {Among various styles of tree drawing reported in the literature, balloon drawing enjoys a desirable feature of displaying tree structures in a rather balanced fashion. Each subtree in the balloon drawing of a tree is enclosed in a circle. Along any path from the root node, the radius of each circle reflects the number of descendants associated with the root node of the subtree. In this paper, we investigate various issues related to balloon drawings of rooted trees from the algorithmic viewpoint. First, we design an efficient algorithm to optimize the angular resolution and the aspect ratio for the balloon drawings of rooted unordered trees. For the case of ordered trees for which the center of the enclosing circle of a subtree need not coincide with the root of the subtree, flipping the drawing of a subtree (along the axis from the parent to the root of the subtree) might change both the aspect ratio and the angular resolution of the drawing. We show that optimizing the angular resolution as well as the aspect ratio with respect to this type of rooted ordered trees is reducible to the perfect matching problem for bipartite graphs, which is solvable in polynomial time. In addition, a related problem concerning the optimization of the drawing area can be modelled as a specific type of nonlinear programming for which there exist several robust algorithms in practice. With a slight modification to the balloon drawing, we are able to generate the drawings of galaxy systems, H-trees, and sparse graphs, which are of practical interest.}, doi = {10.7155/jgaa.00153} } @INPROCEEDINGS{Lin2007a, author = {Chun-Cheng Lin and Hsu-Chun Yen}, title = {Balloon Views of Source Code and Their Multiscalable Font Modes}, pages = {53--58}, abstract = {The majority of program editors available on the market support the view of a directory-explorer style to display only those code lines of interest. Among them, the fisheye and the fractal views of source code (in which each line has a value reflecting the degree of interest and importance) have received a lot of attention in the literature. In information visualization, drawing trees based on fractal theory also plays an interesting role as the so-called balloon drawing of hierarchical data includes two models: the fractal and the SNS (subtrees with nonuniform sizes) models. It is therefore natural to consider a new source code visualization style based on the SNS model of balloon drawing. A main feature of the SNS view is that the value of each line reflects the number of its descendants when the source code is viewed as a tree structure. Unlike the view of a directory-explorer style, the multiscalable font mode (which was originally utilized in the fractal view of source code) displays all the lines in such a way that each line has the font size proportional to its value. In this paper, we investigate various issues concerning the multiscalable font modes of the fish-eye, the fractal, and the SNS views of source code, in hope of providing guidelines for the programmer to better comprehend the program code in practice.}, doi = {10.1109/IV.2007.30}, year = {2007}, booktitle = {IV'07: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Remo Aslak Burkhard and Georges Grinstein and Urska Cvek and Marjan Trutschl and Liz Stuart and Theodor G. Wyeld and Gennady Andrienko and Jason Dykes and Mikael Jern and Dennis Groth and Anna Ursyn}, publisher = {IEEE Computer Society}, isbn = {0769529003} } @ARTICLE{Lin2007b, author = {Yaw-Ling Lin and Po-Shun Yu}, title = {Visualizing Phylogenetic Trees by Spring-Embedder Models}, journal = {Journal of Computers}, year = {2007}, volume = {18}, number = {2}, abstract = {A phylogenetic tree is a graphical representation of the evolutionary relationship between taxonomic groups. The term phylogeny refers to the evolution or historical development of a plant or animal species, or even a human tribe or similar group. In order to make ourself to understand the structure of phylogenetic tree. We present a spring-embedder model for drawing rooted and unrooted phylogenetic trees with straight edges. Our heuristic strives for uniform edge lengths, and we develop it in analogy to forces in natural systems, for a simple, elegant, conceptually intuitive, and efficient algorithm. These algorithms are implemented on a web-based phylogeny visualization system that interoperates with existing tools developed for phylogenetic processing including CLUSTAL W, PHYLIP, PAUP. The molecular biologists can also manually construct their phylogenetic tree via existing system in, e.g., the Phylip format produced by CLUSTAL W as input format of the web system to which this data is to be fed.}, url = {http://www.joc.iecs.fcu.edu.tw/Published%20Vol_18_No_2.files/10_JOC95006_PRINT.pdf} } @MASTERSTHESIS{Lin2008, author = {Xiaochuan Lin}, title = {Algorithm for Improving the Aspect Ratio of Treemaps}, school = {Dalhousie University, Halifax, CA}, year = {2008}, url = {http://web.cs.dal.ca/~farrag/lin.doc} } @ARTICLE{Lin2010, author = {Chun-Cheng Lin and Hsu-Chun Yen and Sheung-Hung Poon and Jia-Hao Fan}, title = {Complexity analysis of balloon drawing for rooted trees}, journal = {arXiv.org e-print service}, year = {2010}, volume = {arXiv:1004.2338v1}, abstract = {In a balloon drawing of a tree, all the children under the same parent are placed on the circumference of the circle centered at their parent, and the radius of the circle centered at each node along any path from the root reflects the number of descendants associated with the node. Among various styles of tree drawings reported in the literature, the balloon drawing enjoys a desirable feature of displaying tree structures in a rather balanced fashion. For each internal node in a balloon drawing, the ray from the node to each of its children divides the wedge accommodating the subtree rooted at the child into two sub-wedges. Depending on whether the two sub-wedge angles are required to be identical or not, a balloon drawing can further be divided into two types: even sub-wedge and uneven sub-wedge types. In the most general case, for any internal node in the tree there are two dimensions of freedom that affect the quality of a balloon drawing: (1) altering the order in which the children of the node appear in the drawing, and (2) for the subtree rooted at each child of the node, flipping the two sub-wedges of the subtree. In this paper, we give a comprehensive complexity analysis for optimizing balloon drawings of rooted trees with respect to angular resolution, aspect ratio and standard deviation of angles under various drawing cases depending on whether the tree is of even or uneven sub-wedge type and whether (1) and (2) above are allowed. It turns out that some are NP-complete while others can be solved in polynomial time. We also derive approximation algorithms for those that are intractable in general.}, url = {http://arxiv.org/abs/1004.2338v1} } @ARTICLE{Lin2011, author = {Chun-Cheng Lin and Hsu-Chun Yen and Sheung-Hung Poon and Jia-Hao Fan}, title = {Complexity analysis of balloon drawing for rooted trees}, journal = {Theoretical Computer Science}, year = {2011}, volume = {412}, pages = {430--447}, number = {4-5}, abstract = {In a balloon drawing of a tree, all the children under the same parent are placed on the circumference of the circle centered at their parent, and the radius of the circle centered at each node along any path from the root reflects the number of descendants associated with the node. Among various styles of tree drawings reported in the literature, the balloon drawing enjoys a desirable feature of displaying tree structures in a rather balanced fashion. For each internal node in a balloon drawing, the ray from the node to each of its children divides the wedge accommodating the subtree rooted at the child into two sub-wedges. Depending on whether the two sub-wedge angles are required to be identical or not, a balloon drawing can further be divided into two types: even sub-wedge and uneven sub-wedge types. In the most general case, for any internal node in the tree there are two dimensions of freedom that affect the quality of a balloon drawing: (1) altering the order in which the children of the node appear in the drawing, and (2) for the subtree rooted at each child of the node, flipping the two sub-wedges of the subtree. In this paper, we give a comprehensive complexity analysis for optimizing balloon drawings of rooted trees with respect to angular resolution, aspect ratio and standard deviation of angles under various drawing cases depending on whether the tree is of even or uneven sub-wedge type and whether (1) and (2) above are allowed. It turns out that some are NP-complete while others can be solved in polynomial time. We also derive approximation algorithms for those that are intractable in general.}, doi = {10.1016/j.tcs.2010.10.015} } @ARTICLE{Linsen2011, author = {Lars Linsen and Sabine Behrendt}, title = {Linked Treemap: A {3D} Treemap-nodelink layout for visualizing hierarchical structures}, journal = {Computational Statistics}, year = {2011}, volume = {26}, pages = {679--697}, number = {4}, abstract = {Hierarchical structures are present in many different areas of our daily life as well as in sciences. Visualization methods are quite commonly applied to support comprehension of the more complex structures. Nodelinks and treemaps are two widely spread directions of such visualization methods. Visualizations using nodelinks have the advantage of explicitly displaying the hierarchical relations between entities. Visualizations using treemaps, on the other hand, allow for a good global understanding of the present entities and some of their properties. We present a visualization tool for hierarchical structures that combines the advantages of treemaps and nodelinks by naturally incorporating them into a 3D layout. The nodelink is built upon the treemap in a direction orthogonal to the treemap plane. Our visualization tool supports various navigation techniques suitable for different analysis tasks. First, the user interaction allows users to render subtrees of the nodelink transparently. Second, the various levels can be explored separately in an intuitive fashion by sliding its plane through the orthogonal nodelink layout and, thus, moving the treemap to the respective level of the hierarchy. Third, zooming into regions of interest is supported by using a focus+context technique that operates on the combined 3D layout. We demonstrate the efficacy and efficiency of our system for visual exploration purposes in a case study that uses our system as a file explorer. In this context, we perform a user study that evaluates our approach and allows for a comparison to other existing approaches.}, doi = {10.1007/s00180-011-0272-2} } @INPROCEEDINGS{Liu2006, author = {Shixia Liu and Nan Cao and Hao Lv and Hui Su}, title = {The visual funding navigator: Analysis of the {NSF} funding information}, pages = {882--883}, abstract = {This paper presents an interactive visualization toolkit for navigating and analyzing the National Science Foundation (NSF) funding information. Our design builds upon an improved 2.5D treemap layout and the stacked graph to contribute customized techniques for visually navigating and interacting with the hierarchical data of NSF programs and proposals. Furthermore, an incremental layout method is adopted to handle information on a large scale. The improved treemap visualization will help to visually analyze the static funding related data and the stacked graph is utilized to analyze the time-series data. Through these visual analysis techniques, research trends of NSF, popular NSF programs are quickly identified.}, doi = {10.1145/1183614.1183778}, year = {2006}, booktitle = {CIKM'06: Proceedings of the ACM International Conference on Information and Knowledge Management}, publisher = {ACM Press}, isbn = {1595934332} } @INPROCEEDINGS{Liu2008, author = {Shixia Liu and Nan Cao and Hao Lv}, title = {Interactive Visual Analysis of the {NSF} Funding Information}, pages = {183--190}, abstract = {This paper presents an interactive visualization toolkit for navigating and analyzing the National Science Foundation (NSF) funding information. Our design builds upon the treemap layout and the stacked graph to contribute customized techniques for visually navigating and interacting with the hierarchical data of NSF programs and proposals, supporting visual search and analysis, and allowing the user to make informed decision. In this visualization toolkit, we propose two visualization techniques to simplify the navigation of the hierarchical data: 2.5 Dimensional treemaps to make the hierarchical structure more easily to be recognized, and labeled treemap to help the user to get a clear overview of the content of the structure and make the internal area of rectangles correspond to the weights of the data set. Furthermore, an incremental layout method is adopted to handle information on a large scale. The improved treemap visualization will help to visually analyze the static funding data and the stacked graph is utilized to analyze the time-series data. Through these visual analysis techniques, research trends of NSF, popular NSF programs are quickly identified. The primary contribution is a demonstration of novel ways to effectively present and analyze NSF funding data.}, doi = {10.1109/PACIFICVIS.2008.4475475}, year = {2008}, booktitle = {PacificVis'08: Proceedings of the IEEE Pacific Visualization Symposium}, editor = {Issei Fujishiro and Hua Li and Kwan-Liu Ma}, publisher = {IEEE Computer Society}, isbn = {9781424419661} } @INPROCEEDINGS{LiWei2013, author = {Gong Li-wei and Chen Yi and Zhang Xin-yue and Sun Yue-hong}, title = {A hierarchical data visualization algorithm: Self-adapting Sunburst algorithm}, pages = {185--190}, abstract = {Sunburst is a hierarchical data visualization method which is filled by radial sectors, for the problem that sectors of Sunburst are placed in disorder and space utilization rate is low, Self-Adapting Sunburst Algorithm (SASA) has been proposed. Nodes are allocated their areas according to their attribute value, and siblings of same parents are made in ascending order according to the size of areas, adjusting the position of sectors. Meanwhile, based on total number of nodes in each layer, SASA dynamically determines width of this circular ring, following the principle "more nodes wider circular ring and fewer nodes thinner circular ring", and in this way, it can optimize the size of nested ring in Sunburst and improve space utilization rate. Finally, User Locating Efficiency (ULE) and Arc Ratio (AR) is put forward to examine SASA, Experimental results show that this algorithm can indeed optimize sector's arrangement, as well as make space utilization better.}, doi = {10.1109/ICVRV.2013.36}, year = {2013}, booktitle = {ICVRV'13: Proceedings of the International Conference on Virtual Reality and Visualization}, editor = {Xiaopeng Zhang and Zhong Zhou and Qing Wang and Xun Luo}, publisher = {IEEE Computer Society}, isbn = {9780769551500} } @ARTICLE{Lott2015, author = {Steffen C. Lott and B\"orn Vo{\ss} and Wolfgang R. Hess and Claudia Steglich}, title = {{CoVennTree}: A new method for the comparative analysis of large datasets}, journal = {Frontiers in Genetics}, year = {2015}, volume = {6}, pages = {1--21}, number = {43}, abstract = {The visualization of massive datasets, such as those resulting from comparative metatranscriptome analyses or the analysis of microbial population structures using ribosomal RNA sequences, is a challenging task. We developed a new method called CoVennTree (Comparative weighted Venn Tree) that simultaneously compares up to three multifarious datasets by aggregating and propagating information from the bottom to the top level and produces a graphical output in Cytoscape. With the introduction of weighted Venn structures, the contents and relationships of various datasets can be correlated and simultaneously aggregated without losing information. We demonstrate the suitability of this approach using a dataset of 16S rDNA sequences obtained from microbial populations at three different depths of the Gulf of Aqaba in the Red Sea. CoVennTree has been integrated into the Galaxy ToolShed and can be directly downloaded and integrated into the user instance.}, url = {http://journal.frontiersin.org/Journal/10.3389/fgene.2015.00043} } @INPROCEEDINGS{Lou2008, author = {Xinghua Lou and Shixia Liu and Tianshu Wang}, title = {{FanLens}: A Visual Toolkit for Dynamically Exploring the Distribution of Hierarchical Attributes}, pages = {151--158}, abstract = {Radial, space-filling visualization is very useful for representing the distribution of attributes in hierarchical data; however it also suffers from its drawbacks in terms of view transition, context preservation, thin slices, flexibility and large sized data support. To address these problems, we propose FanLens, an enhancement upon existing approaches with new features like incremental layout and fisheye distortion based selecting. This visual toolkit also features dynamic hierarchy specification, dynamic visual property mapping, smooth animation, etc. We illustrate the effectiveness of our technique with two examples of case study and results from informal user experiments.}, doi = {10.1109/PACIFICVIS.2008.4475471}, year = {2008}, booktitle = {PacificVis'08: Proceedings of the IEEE Pacific Visualization Symposium}, editor = {Issei Fujishiro and Hua Li and Kwan-Liu Ma}, publisher = {IEEE Computer Society}, isbn = {9781424419661} } @INPROCEEDINGS{Lu2008, author = {Hao R. L\"u and James Fogarty}, title = {Cascaded {Treemaps}: Examining the Visibility and Stability of Structure in {Treemaps}}, pages = {259--266}, abstract = {Treemaps are an important and commonly-used approach to hierarchy visualization, but an important limitation of treemaps is the difficulty of discerning the structure of a hierarchy. This paper presents cascaded treemaps, a new approach to treemap presentation that is based in cascaded rectangles instead of the traditional nested rectangles. Cascading uses less space to present the same containment relationship, and the space savings enable a depth effect and natural padding between siblings in complex hierarchies. In addition, we discuss two general limitations of existing treemap layout algorithms: disparities between node weight and relative node size that are introduced by layout algorithms ignoring the space dedicated to presenting internal nodes, and a lack of stability when generating views of different levels of treemaps as a part of supporting interactive zooming. We finally present a two-stage layout process that addresses both concerns, computing a stable structure for the treemap and then using that structure to consider the presentation of internal nodes when arranging the treemap. All of this work is presented in the context of two large real-world hierarchies, the Java package hierarchy and the eBay auction hierarchy.}, url = {http://portal.acm.org/citation.cfm?doid=1375714.1375758}, year = {2008}, booktitle = {GI'08: Proceedings of the Graphics Interface Conference}, editor = {Lyn Bartram and Chris Shaw}, publisher = {Canadian Information Processing Society}, isbn = {9781568814230} } @PATENT{Lu2013, author = {Hao Lu and Shi Xia Liu and Martin Wattenberg and Xi Jun Ma}, title = {Constructing a {Labeled Treemap} with Balanced Layout}, number = {US 8443281 B2}, year = {2013}, abstract = {The present invention provides a method and system for constructing a labeled treemap with balanced layout. A range of possible densities of leaf nodes based on designated weights of the leaf nodes and a designated treemap region is determined. A range of possible densities is then searched for a density that could be fitted on and a labeled treemap that could fit on the density. The labeled treemap is presented on a specified display region. By introducing the concept of density into labeled treemap, the present invention ensures the area of region occupied by each leaf node in the constructed labeled treemap is approximately corresponding to the weight of the node, and avoids the case of invisible leaf node in a treemap.}, url = {http://www.freepatentsonline.com/8443281.html} } @INPROCEEDINGS{Luboschik2007, author = {Martin Luboschik and Heidrun Schumann}, title = {Explode to Explain -- Illustrative Information Visualization}, pages = {301--307}, abstract = {Due to complexity, modern visualization techniques for large data volumes and complex interrelationships are difficult to understand for non-expert users and even for expert users the visualization result may be difficult to interpret. Often the limited screen space and the risk of occlusion hinders a meaningful explanation of techniques or datasets by additional visual elements. This paper presents a novel way how views from information visualization can be adapted by the use of the well-known illustrative technique "exploded view", to successfully face the problems described above. The application of exploded views gains screen space for an explanation in a smart way and acts explanatory itself. With our approach of illustrating visual representations, the understanding of complex visualization techniques is eased and new comprehensible views on data are given.}, doi = {10.1109/IV.2007.50}, year = {2007}, booktitle = {IV'07: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Remo Aslak Burkhard and Georges Grinstein and Urska Cvek and Marjan Trutschl and Liz Stuart and Theodor G. Wyeld and Gennady Andrienko and Jason Dykes and Mikael Jern and Dennis Groth and Anna Ursyn}, publisher = {IEEE Computer Society}, isbn = {0769529003} } @ARTICLE{Manning1988, author = {Joseph Manning and Mikhail J. Atallah}, title = {Fast detection and display of symmetry in trees}, journal = {Congressus Numerantium}, year = {1988}, volume = {64}, pages = {159--169}, abstract = {The automatic construction of good drawings of abstract graphs is a problem of practical importance. Displaying symmetry appears as one of the main criteria for achieving goodness. An expression is obtained for the maximum number of axial symmetries of a tree which can be simultaneously displayed in a single drawing, and an algorithm is presented for constructing such a maximally-symmetric drawing. Similar results are also obtained for rotational symmetries in trees. The algorithms run in time which is linear in the size of the tree, and hence are optimal.} } @INPROCEEDINGS{Marriott2007, author = {Kim Marriott and Peter Sbarski}, title = {Compact layout of layered trees}, pages = {7--14}, abstract = {The standard layered drawing convention for trees in which the vertical placement of a node is given by its level in the tree and each node is centered between its children can lead to drawings which are quite wide. We present two new drawing conventions which reduce the layout width to be less than some maximum width while still maintaining the essential layered drawing convention. These conventions relax the requirement that a parent must be exactly placed midway between its children, and instead make this a preference which can be violated if this is required for the layout to fit into the required width. Both drawing conventions give rise to a simple kind of quadratic programming problem. We give an iterative gradient projection algorithm for solving this kind of problem, and also a linear time heuristic algorithm. Our algorithms are practical: a tree with three thousand nodes can be laid out in less than a hundred milliseconds with either algorithm.}, url = {http://dl.acm.org/citation.cfm?id=1273751}, year = {2007}, booktitle = {ACSC'07: Proceedings of the Australasian Conference on Computer Science}, editor = {Gillian Dobbie}, publisher = {Australian Computer Society}, isbn = {1920682430} } @ARTICLE{Marriott2011, author = {Kim Marriott and Peter Sbarski and Tim van Gelder and Daniel Prager and Andy Bulka}, title = {{Hi-Trees} and Their Layout}, journal = {IEEE Transactions on Visualization and Computer Graphics}, year = {2011}, volume = {17}, pages = {290--304}, number = {3}, abstract = {We introduce hi-trees, a new visual representation for hierarchical data in which, depending on the kind of parent node, the child relationship is represented using either containment or links. We give a drawing convention for hi-trees based on the standard layered drawing convention for rooted trees, then show how to extend standard bottom-up tree layout algorithms to draw hi-trees in this convention. We also explore a number of other more compact layout styles for layout of larger hi-trees and give algorithms for computing these. Finally, we describe two applications of hi-trees: argument mapping and business decision support.}, doi = {10.1109/TVCG.2010.45} } @MASTERSTHESIS{Matela2010, author = {Mateusz Matela}, title = {Metody wizualizacji dla zmieniajacych sie w czasie zbiorow danych o strukturze hierarchicznej}, school = {Poznan University of Technology}, year = {2010}, url = {http://project.carrot2.org/publications/matela-2010-foamtree.pdf} } @MISC{Matela2011, author = {Mateusz Matela and Dawid Weiss}, title = {{FoamTree}: Physics-inspired tree map}, url = {http://carrotsearch.com/foamtree}, year = {2011}, note = {retrieved 18-JUN-2011} } @ARTICLE{Meier1996, author = {John Meier and Clifford A. Reiter}, title = {Fractal representations of {Cayley} graphs}, journal = {Computers and Graphics}, year = {1996}, volume = {20}, pages = {163--170}, number = {1}, abstract = {The visualization of Cayley graphs for many groups is possible using 3-D models. Most of our examples are Cayley graphs of infinite groups where we exploit automatic structures to efficiently produce computer images of the Cayley graphs. The infinite groups are visualized using fractal rescaling so that the infinite graph projects into a bounded domain. Varying the color choice for these fractal representations of the Cayley graphs allows the visual recognition of features such as positivity of the total exponent of the words.}, doi = {10.1016/0097-8493(95)00101-8} } @TECHREPORT{Melancon1998, author = {Guy Melan\c{c}on and Ivan Herman}, title = {Circular drawings of rooted trees}, institution = {Centrum voor Wiskunde en Informatica}, year = {1998}, number = {INS-R9817}, abstract = {We describe an algorithm producing circular layouts for trees, that is drawings, where subtrees of a node lie within circles, and these circles are themselves placed on the circumference of a circle. The complexity and methodology of our algorithm compares to Reingold and Tilford's algorithm for trees. Moreover, the algorithm naturally admits distortion transformations of the layout. This, added to its low complexity, makes it very well suited to be used in an interactive environment.}, url = {http://repository.cwi.nl/search/fullrecord.php?publnr=4602} } @INPROCEEDINGS{Metaxas1994, author = {Panagiotis T. Metaxas and Grammati E. Pantziou and Antonis Symvonis}, title = {Parallel h-v drawings of binary trees}, pages = {487--495}, abstract = {In this paper we present a method to obtain optimal h-v and inclusion drawings in parallel. Based on parallel tree contraction, our method computes optimal (with respect to a class of cost functions of the enclosing rectangle) drawings in O(log2n) parallel time by using a polynomial number of EREW processors. The method can be extended to compute optimal inclusion layouts in the case where each leaf l of the tree is represented by rectangle l x*l y. Our method also yields an NC algorithm for the slicing floorplanning problem. Whether this problem was in NC was an open question.}, doi = {10.1007/3-540-58325-4_215}, year = {1994}, booktitle = {ISAAC'94: Proceedings of the International Symposium on Algorithms and Computations}, editor = {Ding-Zhu Du and Xiang-Sun Zhang}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {3540583254}, } @ARTICLE{Metaxas1998, author = {Panagiotis T. Metaxas and Grammati E. Pantziou and Antonis Symvonis}, title = {A note on parallel algorithms for optimal h-v drawings of binary trees}, journal = {Computational Geometry}, year = {1998}, volume = {9}, pages = {145--158}, number = {3}, abstract = {In this paper we present a method to obtain optimal h-v drawings in parallel. Based on parallel tree contraction, our method computes optimal (with respect to a class of cost functions of the enclosing rectangle) drawings in O(log2n) parallel time by using a polynomial number of EREW processors. The number of processors reduces substantially when we study minimum area drawings. Our work places the problem of obtaining optimal size h-v drawings in NC, presenting the first algorithm with polylogarithmic time complexity.}, doi = {10.1016/S0925-7721(96)00018-1} } @INPROCEEDINGS{Miller2011, author = {Robert Miller and Vadim Mozhayskiy and Ilias Tagkopoulos and Kwan-Liu Ma}, title = {{EVEVis}: A Multi-Scale Visualization System for Dense Evolutionary Data}, year = {2011}, pages = {143--150}, abstract = {Evolutionary simulations can produce datasets consisting of thousands or millions of separate entities, complete with their genealogical relationships. Biologists must examine this data to determine when and where these entities have changed, both on an individual basis and on a population-wide basis. Therefore, desirable features of a visualization system for evolutionary data are the capability of showing the status of the population at any given moment in time, good scalability, and smooth transition between high-level and low-level views. We propose a multi-scale visualization method, including a novel tree layout that both shows population status over time and can easily scale to very large populations. From this layout, the user can navigate to visualizations for moments in time or for individual entities. We demonstrate the effectiveness of the visualization on an existing evolutionary simulation called EVE: Evolution in Variable Environments.}, doi = {10.1109/BioVis.2011.6094059}, year = {2011}, booktitle = {BioVis'11: Proceedings of the IEEE Symposium on Biological Data Visualization}, publisher = {IEEE Computer Society} } @INPROCEEDINGS{Miyazaki2009, author = {Reiko Miyazaki and Takayuki Itoh}, title = {An Occlusion-Reduced 3D Hierarchical Data Visualization Technique}, pages = {38--43}, abstract = {Occlusion is an important problem to be solved for readability improvement of 3D visualization techniques. This paper presents an occlusion reduction technique for cityscape-style 3D visualization techniques. The paper first presents an algorithm for occlusion reduction. It generates bounding boxes of 3D objects on the 2D display space, moves them to reduce their overlap, and finally reversely projects their movements onto the 3D space. The paper then presents an application of the algorithm to our own hierarchical data visualization technique, and a music browser based on the technique. The paper also shows several numerical evaluations that denote the effectiveness of the presented technique.}, doi = {10.1109/IV.2009.32}, year = {2009}, booktitle = {IV'09: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Liz Stuart and Theodor G. Wyeld and Mikael Jern and Gennady Andrienko and Nasrullah Memon and Reda Alhajj and Remo Aslak Burkhard and Georges Grinstein and Dennis Groth and Anna Ursyn and Jimmy Johansson and Camilla Forsell and Urska Cvek and Marjan Trutschi and Francis T. Marchese and Carsten Maple and Andrew J. Cowell and Andrew Vande Moere}, publisher = {IEEE Computer Society}, isbn = {9780769537337} } @INPROCEEDINGS{Mizukoshi2006, author = {Daisuke Mizukoshi and Yukio Hori and Tomonori Gotoh}, title = {Extension models of {Cone Tree} Visualizations to Large scale Knowledge base with Semantic Relations}, pages = {19--20}, abstract = {Cone Tree is an appealing interactive 3D visualization model for hierarchical data structure. In any prior studies, data objects for visualization were constructed by only tree structure, which contained small number of data and nodes. Subject domains in real world for visualization studies have highly complicated relations, which cannot to be expressed in a few nodes and only hierarchical structure. In this paper, we proposed the visualization technique based on cone tree model to apply for a large-scale knowledge base, which has complicated data structure. The EDR Electronic Dictionary as a large-scale knowledge base was used in our study. The visualization system fro EDR was implemented with Java 3D. This paper describes the technique and the implemented system, and discusses some problems on the technique.}, url = {http://wscg.zcu.cz/wscg2006/Papers_2006/Poster/C89-full.pdf}, year = {2006}, booktitle = {WSCG'06: Proceedings of the International Conference in Central Europe on Computer Graphics, Visualization and Computer Vision}, editor = {Joaquim Jorge and Vaclav Skala}, publisher = {University of West Bohemia}, isbn = {8086943046}, } @ARTICLE{Moen1990, author = {Sven Moen}, title = {Drawing dynamic trees}, journal = {IEEE Software}, year = {1990}, volume = {7}, pages = {21--28}, number = {4}, abstract = {A tree-drawing algorithm that addresses the weaknesses of current approaches to constructing graphical user interfaces is presented. Present algorithms either do not let you draw tree nodes of varying shapes and sizes or they draw such trees in a way that does not produce trees as compact as they could be, which is especially important when diagramming a large system. Also, they cannot reuse layout information when the trees changes, so after every change the layout must be recomputed and the tree redrawn. The main difference between these traditional approaches and the author's approach is that his algorithm is more geometric. Unlike other algorithms, it uses an explicit representation of node and subtree contours, and it stores every contour as a polygon. It has three advantages over traditional algorithms. It allows one to draw trees with nodes of any polygonal shape compactly. The data structure supports insert and delete operations on subtrees. It is simple to implement, yet flexible.}, doi = {10.1109/52.56447} } @INPROCEEDINGS{MohammadiAragh2005, author = {Mahnas Jean Mohammadi-Aragh and T. J. Jankun-Kelly}, title = {MoireTrees: Visualization and Interaction for Multi-Hierarchical Data}, pages = {231--238}, abstract = {Visualizing hierarchical data is one of the core areas of information visualization. Most of these techniques focus on single hierarchies - hierarchies with a single root element and a single path to each element. In contrast, this work focuses on the browsing of multi-hierarchies - hierarchies with multiple roots or multiple paths per element. A radial focus+context display algorithm and interaction methods are introduced to explore such multi-hierarchical data. A series of examples demonstrate the effectiveness of our new visualization.}, doi = {10.2312/VisSym/EuroVis05/231-238}, year = {2005}, booktitle = {EuroVis'05: Proceedings of the Joint Eurographics - IEEE VGTC Symposium on Visualization}, editor = {Ken Brodlie and David Duke and Kenneth I. Joy}, publisher = {Eurographics Association}, isbn = {3905673193} } @INPROCEEDINGS{Mondal2011, author = {Debajyoti Mondal and Muhammad Jawaherul Alam and Md. Saidur Rahman}, title = {Minimum-Layer Drawings of Trees}, pages = {221--232}, abstract = {A layered drawing of a tree T is a planar straight-line drawing of T, where the vertices of T are placed on some horizontal lines called layers. A minimum-layer drawing of T is a layered drawing of T on k layers, where k is the minimum number of layers required for any layered drawing of T. In this paper we give a linear-time algorithm for obtaining minimum-layer drawings of trees.}, doi = {10.1007/978-3-642-19094-0_23}, year = {2011}, booktitle = {WALCOM'11: Proceedings of the International Workshop on Algorithms and Computation}, editor = {Naoki Katoh and Amit Kumar}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783642190933}, } @INPROCEEDINGS{Moret2009, author = {Philippe Moret and Walter Binder and Danilo Ansaloni and Alex Villaz\'on}, title = {Visualizing Calling Context profiles with Ring Charts}, pages = {33-36}, abstract = {Calling context profiling is an important technique for analysing the performance of object-oriented software with complex inter-procedural control flow. A common data structure is the Calling Context Tree (CCT), which stores dynamic metrics, such as CPU time, separately for each calling context. As CCTs may comprise millions of nodes, there is need for a condensed visualization that eases the location of performance bottlenecks. In this paper, we introduce Calling Context Ring Charts, a new compact visualization for CCTs, where callee methods are represented in ring segments surrounding the caller's ring segment. In order to reveal hot methods, their callers, and callees, the ring segments can be sized according to a chosen dynamic metric.}, doi = {10.1109/VISSOF.2009.5336425}, year = {2009}, booktitle = {VisSoft'09: Proceedings of the IEEE International Workshop on Visualizing Software for Understanding and Analysis}, editor = {Michele Lanza and Hausi A. M\"uller and Margaret-Anne Storey}, publisher = {IEEE Computer Society}, isbn = {9781424450251} } @ARTICLE{Moret2010, author = {Philippe Moret and Walter Binder and Alex Villaz\'on and Danilo Ansaloni and Abbas Heydarnoori}, title = {Visualizing and exploring profiles with calling context ring charts}, journal = {Software -- Practice and Experience}, year = {2010}, volume = {40}, pages = {825--847}, number = {9}, abstract = {Calling context profiling is an important technique for analyzing the performance of object-oriented software with complex inter-procedural control flow. The Calling Context Tree (CCT) is a common data structure that stores dynamic metrics, such as CPU time, separately for each calling context. As CCTs may comprise millions of nodes, there is a need for a condensed visualization that eases the localization of performance bottlenecks. In this article, we discuss Calling Context Ring Charts (CCRCs), a compact visualization for CCTs, where callee methods are represented in ring segments surrounding the caller's ring segment. In order to reveal hot methods, their callers, and callees, the ring segments can be sized according to a chosen dynamic metric. We describe two case studies where CCRCs help us to detect and fix performance problems in applications. A performance evaluation also confirms that our implementation can efficiently handle large CCTs.}, doi = {10.1002/spe.985} } @INPROCEEDINGS{Munzner1997, author = {Tamara Munzner}, title = {H3: laying out large directed graphs in {3D} hyperbolic space}, pages = {2--10}, abstract = {We present the H3 layout technique for drawing large directed graphs as node-link diagrams in 3D hyperbolic space. We can lay out much larger structures than can be handled using traditional techniques for drawing general graphs because we assume a hierarchical nature of the data. We impose a hierarchy on the graph by using domain-specific knowledge to find an appropriate spanning tree. Links which are not part of the spanning tree do not influence the layout but can be selectively drawn by user request. The volume of hyperbolic 3-space increases exponentially, as opposed to the familiar geometric increase of euclidean 3-space. We exploit this exponential amount of room by computing the layout according to the hyperbolic metric. We optimize the cone tree layout algorithm for 3D hyperbolic space by placing children on a hemisphere around the cone mouth instead of on its perimeter. Hyperbolic navigation affords a Focus+Context view of the structure with minimal visual clutter. We have successfully laid out hierarchies of over 20,000 nodes. Our implementation accommodates navigation through graphs too large to be rendered interactively by allowing the user to explicitly prune or expand subtrees.}, doi = {10.1109/INFVIS.1997.636718}, year = {1997}, booktitle = {InfoVis'97: Proceedings of the IEEE Symposium on Information Visualization}, editor = {John Dill and Nahum D. Gershon}, publisher = {IEEE Computer Society}, isbn = {0818681896} } @ARTICLE{Munzner1998, author = {Tamara Munzner}, title = {Exploring large graphs in {3D} hyperbolic space}, journal = {IEEE Computer Graphics and Applications}, year = {1998}, volume = {18}, pages = {18--23}, number = {4}, abstract = {Drawing graphs as nodes connected by links is visually compelling but computationally difficult. Hyperbolic space and spanning trees can reduce visual clutter, speed up layout, and provide fluid interaction. This article briefly describes a software system that explicitly attempts to handle much larger graphs than previous systems and support dynamic exploration rather than final presentation. It then discusses the applicability of this system to goals beyond simple exploration. A software system that supports graph exploration should include both a layout and an interactive drawing component. I have developed new algorithms for both layout and drawing (H3 and H3Viewer). The H3Viewer drawing algorithm remains under development, so this article presents preliminary results. I have implemented a software library that uses these algorithms. It can handle graphs of more than 100,000 edges by using a spanning tree as the backbone for the layout and drawing algorithms.}, doi = {10.1109/38.689657} } @INPROCEEDINGS{Munzner1998a, author = {Tamara Munzner}, title = {Drawing Large Graphs with {H3Viewer} and {Site Manager}}, pages = {384--393}, abstract = {We demonstrate the H3Viewer graph drawing library, which can be run from a standalone program or in conjunction with other programs such as SGI's Site Manager application. Our layout and drawing algorithms support interactive navigation of large graphs up to 100,000 edges. We present an adaptive drawing algorithm with a guaranteed frame rate. Both layout and navigation occur in 3D hyperbolic space, which provides a view of a large neighborhood around an easily changeable point of interest. We find an appropriate spanning tree to use as the backbone for fast layout and uncluttered drawing, and non-tree links can be displayed on demand. Our methods are appropriate when node or link annotations can guide the choice of a good parent from among all of the incoming links. Such annotations can be constructed using only a small amount of domain-specific knowledge, thus rendering tractable many graphs which may seem rather densely connected at first glance.}, doi = {10.1007/3-540-37623-2_30}, year = {1998}, booktitle = {GD'98: Proceedings of the International Symposium on Graph Drawing}, editor = {Sue H. Whitesides}, publisher = {Springer}, series = {Lecture Notes in Computer Science}, isbn = {9783540654735}, } @PHDTHESIS{Munzner2000, author = {Tamara Munzner}, title = {Interactive visualization of large graphs and networks}, school = {Stanford University}, year = {2000}, abstract = {Many real-world domains can be represented as large node-link graphs: backbone Internet routers connect with 70,000 other hosts, mid-sized Web servers handle between 20,000 and 200,000 hyperlinked documents, and dictionaries contain millions of words defined in terms of each other. Computational manipulation of such large graphs is common, but previous tools for graph visualization have been limited to datasets of a few thousand nodes. Visual depictions of graphs and networks are external representations that exploit human visual processing to reduce the cognitive load of many tasks that require understanding of global or local structure. We assert that the two key advantages of computer-based systems for information visualization over traditional paper-based visual exposition are interactivity and scalability. We also argue that designing visualization software by taking the characteristics of a target user's task domain into account leads to systems that are more effective and scale to larger datasets than previous work. This thesis contains a detailed analysis of three specialized systems for the interactive exploration of large graphs, relating the intended tasks to the spatial layout and visual encoding choices. We present two novel algorithms for specialized layout and drawing that use quite different visual metaphors. The H3 system for visualizing the hyperlink structures of web sites scales to datasets of over 100,000 nodes by using a carefully chosen spanning tree as the layout backbone, 3D hyperbolic geometry for a Focus+Context view, and provides a fluid interactive experience through guaranteed frame rate drawing. The Constellation system features a highly specialized 2D layout intended to spatially encode domain-specific information for computational linguists checking the plausibility of a large semantic network created from dictionaries. The Planet Multicast system for displaying the tunnel topology of the Internet's multicast backbone provides a literal 3D geographic layout of arcs on a globe to help MBone maintainers find misconfigured long-distance tunnels. Each of these three systems provides a very different view of the graph structure, and we evaluate their efficacy for the intended task. We generalize these findings in our analysis of the importance of interactivity and specialization for graph visualization systems that are effective and scalable.}, url = {http://graphics.stanford.edu/papers/munzner_thesis/} } @ARTICLE{Munzner2003, author = {Tamara Munzner and Fran\c{c}ois Guimbreti\'ere and Serdar Tasiran and Li Zhang and Yunhong Zhou}, title = {{TreeJuxtaposer}: Scalable tree comparison using Focus+Context with guaranteed visibility}, journal = {ACM Transactions on Graphics}, year = {2003}, volume = {22}, pages = {453--462}, number = {3}, abstract = {Structural comparison of large trees is a difficult task that is only partially supported by current visualization techniques, which are mainly designed for browsing. We present TreeJuxtaposer, a system designed to support the comparison task for large trees of several hundred thousand nodes. We introduce the idea of "guaranteed visibility", where highlighted areas are treated as landmarks that must remain visually apparent at all times. We propose a new methodology for detailed structural comparison between two trees and provide a new nearly-linear algorithm for computing the best corresponding node from one tree to another. In addition, we present a new rectilinear Focus+Context technique for navigation that is well suited to the dynamic linking of side-by-side views while guaranteeing landmark visibility and constant frame rates. These three contributions result in a system delivering a fluid exploration experience that scales both in the size of the dataset and the number of pixels in the display. We have based the design decisions for our system on the needs of a target audience of biologists who must understand the structural details of many phylogenetic, or evolutionary, trees. Our tool is also useful in many other application domains where tree comparison is needed, ranging from network management to call graph optimization to genealogy.}, doi = {10.1145/882262.882291} } @MISC{Nadeau2008, author = {David Robert Nadeau}, title = {Visualizing large trees and graphs using a {3D} cone tree layout}, url = {http://nadeausoftware.com/node/83}, year = {2008}, note = {retrieved 30-MAY-2011}, abstract = {Tree and graph structures are often visualized as 2D linear tree diagrams with labeled dots and connecting lines. But when the data grows beyond several dozen nodes, these diagrams become large and awkward. This article looks at a 3D Cone Tree scheme for visualizing trees and graphs with several thousand nodes. I outline the layout algorithm, show examples, and discuss strengths and weaknesses for the approach.} } @INPROCEEDINGS{Neumann2006, author = {Petra Neumann and Sheelagh Carpendale and Anand Agarawala}, title = {{PhylloTrees}: Phyllotactic Patterns for Tree Layout}, pages = {59--66}, abstract = {Motivations for drawing hierarchical structures are probably as diverse as datasets to visualize. This ubiquity of tree structures has lead to a manifold of tree layout algorithms and tree visualization systems. While many tree layouts exist, increasingly massive data sets, expanding computational power, and still relatively limited display space make tree layout algorithms a topic of ongoing interest. We explore the use of nature's phyllotactic patterns to inform the layout of hierarchical data. These naturally occurring patterns provide a non-overlapping, optimal packing when the total number of nodes is not known a priori. We present PhylloTrees, a family of expandable tree layouts based on these patterns.}, doi = {10.2312/VisSym/EuroVis06/059-066}, year = {2006}, booktitle = {EuroVis'06: Proceedings of the Joint Eurographics - IEEE VGTC Symposium on Visualization}, editor = {Beatriz Sousa Santos and Thomas Ertl and Kenneth I. Joy}, publisher = {Eurographics Association}, isbn = {3905673312} } @PATENT{Newman2005, author = {Paula S. Newman and Stuart K. Card}, title = {Method and apparatus for the viewing and exploration of the content of hierarchical information}, number = {US 6944818 B2}, year = {2005}, abstract = {A method for the conversion and display of tree-structured information to a "treetable", a table-like display structure, in which each path from a root to a leaf node is represented by a single column, and cells representing the immediate successors of a node are placed immediately under that node. Variation in the amount of space given to cells within particular columns is used to allow more detail to be given for selected paths and subtrees. Extraction of subparts of a treetable into another such structure is used for deeper exploration of trees. The treetable structure is also suitable for use as a selector and guide to the reading, in auxiliary displays, of the concatenated node content associated with either (a) individual columns (representing full paths), or (b) all successors to a given node.}, url = {http://www.freepatentsonline.com/6944818.html} } @PATENT{Newman2005a, author = {Paula S. Newman and Stuart K. Card}, title = {Method and apparatus for the construction and use of table-like visualizations of hierarchic material}, number = {US 6976212 B2}, year = {2005}, abstract = {A method for the conversion and display of tree-structured information to a "treetable", a table-like display structure, in which each path from a root to a leaf node is represented by a single column, and cells representing the immediate successors of a node are placed immediately under that node. Variation in the amount of space given to cells within particular columns is used to allow more detail to be given for selected paths and subtrees. Extraction of subparts of a treetable into another such structure is used for deeper exploration of trees. The treatable structure is also suitable for use as a selector and guide to the reading, in auxiliary displays, of the concatenated node content associated with either (a) individual columns (representing full paths), or (b) all successors to a given node.}, url = {http://www.freepatentsonline.com/6976212.html} } @INPROCEEDINGS{Nguyen2000, author = {Trong Dung Nguyen and Tu Bao Ho and Hiroshi Shimodaira}, title = {A visualization tool for interactive learning of large decision trees}, pages = {28--35}, abstract = {Decision tree induction is certainly among the most applicable learning techniques due to its power and simplicity. However learning decision trees from large datasets, particularly in data mining, is quite different from learning from small or moderately sized datasets. When learning from large datasets, decision tree induction programs often produce very large trees. How to efficiently visualize trees in the learning process, particularly large trees, is still questionable and currently requires efficient tools. The paper presents a visualization tool for interactive learning of large decision trees, that includes a new visualization technique called T2.5D (Trees 2.5 Dimensions). After a brief discussion on requirements for tree visualizers and related work, the paper focuses on presenting developing techniques for two issues: (1) how to visualize efficiently large decision trees; and (2) how to visualize decision trees in the learning process}, doi = {10.1109/TAI.2000.889842}, year = {2000}, booktitle = {ICTAI'00: Proceedings of the Internationals Conference on Tools with Artificial Intelligence}, publisher = {IEEE Computer Society}, isbn = {0769509096} } @INPROCEEDINGS{Nguyen2002, author = {Quang Vinh Nguyen and Mao Lin Huang}, title = {A Space-Optimized Tree Visualization}, pages = {85--92}, abstract = {We describe a new method for the visualization of tree structured relational data. It can be used especially for the display of very large hierarchies in a 2-dimensional space. We discuss the advantages and limitations of current techniques of tree visualization. Our strategy is to optimize the drawing of trees in a geometrical plane and maximize the utilization of display space by allowing more nodes and links to be displayed at a limit screen resolution. We use the concept of enclosure to partition the entire display space into a collection of local regions that are assigned to all nodes in tree T for the display of their sub-trees and themselves. To enable the exploration of large hierarchies, we use a modified semantic zooming technique to view the detail of a particular part of the hierarchy at a time based on user's interest. Layout animation is also provided to preserve the mental map while the user is exploring the hierarchy by changing zoomed views.}, doi = {10.1109/INFVIS.2002.1173152}, year = {2002}, booktitle = {InfoVis'02: Proceedings of the IEEE Symposium on Information Visualization}, editor = {Pak Chung Wong and Keith Andrews}, publisher = {IEEE Computer Society}, isbn = {076951751X} } @INPROCEEDINGS{Nguyen2002a, author = {Quang Vinh Nguyen and Mao Lin Huang}, title = {Improvements of {Space-Optimized Tree} for Visualizing and Manipulating Very Large Hierarchies}, pages = {75--81}, abstract = {This paper describes some improvements over the original Space-Optimized Tree technique for the visualization and manipulation of very large hierarchies. The new system uses an improved algorithm to calculate geometrical layouts and it also provides better navigation capability. We introduce our new layout algorithm that can make more consistence of the display than the original layout technique made. We also combine DualView (a new focus+context technique) with the current modified semantic zooming in order to interactively navigate through the large and very large hierarchies.}, url = {https://dl.acm.org/citation.cfm?id=1164106}, year = {2002}, booktitle = {VIP'02: Proceedings of the Pan-Sydney Area Workshop on Visual Information Processing}, editor = {Jesse S. Jin and Peter Eades and David Dagan Feng and Hong Yan}, publisher = {Australian Computer Society/CRPIT}, isbn = {1920682015} } @ARTICLE{Nguyen2003, author = {Quang Vinh Nguyen and Mao Lin Huang}, title = {Space-optimized tree: A connection+enclosure approach for the visualization of large hierarchies}, journal = {Information Visualization}, year = {2003}, volume = {2}, pages = {3--15}, number = {1}, abstract = {This paper describes a new approach, space-optimized tree, for the visualization and navigation of tree-structured relational data. This technique can be used especially for the display of very large hierarchies in a two-dimensional space. We discuss the advantages and limitations of current techniques of tree visualization. Our strategy is to optimize the drawing of trees in a geometrical plane and maximize the utilization of display space by allowing more nodes and links to be displayed at a limited screen resolution. Space-optimized tree is a connection+enclosure visualization approach that recursively positions children of a subtree into polygon areas and still uses a node-link diagram to present the entire hierarchical structure. To be able to handle the navigation of large hierarchies, we use a new hybrid viewing technique that combines two viewing methods, the modified semantic zooming and a focus+context technique. While the semantic zooming technique can enlarge a particular viewing area by filtering out the rest of tree structure from the visualization, the focus+context technique allows the user to interactively focus, view and browse the entire visual structure with a reasonable high-density display.}, doi = {10.1057/palgrave.ivs.9500031} } @INPROCEEDINGS{Nguyen2004, author = {Quang Vinh Nguyen and Mao Lin Huang}, title = {Hierarchical Information Visualization using ENCCON Model}, year = {2004}, abstract = {This paper describes a new efficient approach for visualizing large hierarchical information. Our technique is based on the connection + enclosure visualization model from which the area division is used for the recursive positioning of nodes, while a node-link diagram is still drawn to present the entire hierarchical structure. We inherit the advantages of Space-Optimized (SO) Tree technique that can enhance the usability of display space by using area division. However, we replace a set of polygons used in SO Tree by a set of rectangles for the area division. This not only decreases the computation cost in calculating geometrical polygons, but also greatly reduces the human perceptual and cognitive loads spent on understanding the underlying hierarchical structure. We use semantic zooming technique to enlarge a particular viewing area and filter out the rest of structure that is less interested. The navigation is accommodated by animation in order to preserve the mental map.}, url = {http://www.actapress.com/PaperInfo.aspx?PaperID=16436}, year = {2004}, booktitle = {SE'04: Proceedings of the IASTED International Conference on Software Engineering}, editor = {M. H. Hamza}, publisher = {ACTA Press}, isbn = {0889863814} } @INPROCEEDINGS{Nguyen2004a, author = {Quang V. Nguyen and Mao L. Huang}, title = {Visualising file-systems using {ENCCON} model}, pages = {61--65}, abstract = {This paper describes a new approach for visualising the file structures. Our technique uses an enclosure + connection (ENCCON) approach that provides an overall view of the entire file/directory hierarchy that gives a better understanding of the folder-folder and folder-file relationships, and therefore makes easier for the navigation. We firstly use the rectangular regions to present the folders. This allows the user to immediately percept the location, size (number of files contained) and other properties of any particular folder. To enrich the visual attributes of the file structure, we also use a node-link diagram to present the "belonging" relationships. This "belonging" relationship includes folder-folder and folder-file relationships. We use a semantic zooming technique to enlarge the display of files and folders in a particular focused area. The animation is also accommodated in order to preserve the mental map [Bartram 1997] during the navigation.}, url = {http://portal.acm.org/citation.cfm?id=1082121.1082131}, year = {2004}, booktitle = {VIP'04: Proceedings of the Pan-Sydney Area Workshop on Visual Information Processing}, editor = {Massimo Piccardi and Tom Hintz and Sean He and Mao Lin Huang and David Dagan Feng}, publisher = {Australian Computer Society/CRPIT}, isbn = {192068218X} } @ARTICLE{Nguyen2005, author = {Quang Vinh Nguyen and Mao Lin Huang}, title = {{EncCon}: An approach to constructing interactive visualization of large hierarchical data}, journal = {Information Visualization}, year = {2005}, volume = {4}, pages = {1--21}, number = {1}, abstract = {This paper describes a new technique called EncCon for visualizing and navigating large hierarchical information. This technique consists of two components: visualization and navigation. Visualization uses a fast enclosure+connection method to calculate the geometrical layout for the display of large hierarchies in a two-dimensional space. Our technique uses a rectangular division algorithm for recursively positioning the graph. This visualization aims to maximize the utilization of display space while retaining a good geometrical layout as well as a clear (explicit) presentation of the hierarchical structure of graphs. This paper also presents an experimental evaluation of EncCon's layout algorithm. Besides the layout algorithm, EncCon uses a new focus+context viewing technique for the navigation of large hierarchies. We use the zooming+layering concept to achieve the focus+context viewing, rather than the traditional enlarge+embedded concept, which is used by most of the available focus+context techniques. Technically, it employs semi-transparency to achieve the display of two layers of information in z-coordination at the same visualization. Both context view and detail view are drawn at two separate layers. These layers are then displayed in an overlapped manner at the same physical screen space.}, doi = {10.1057/palgrave.ivs.9500087} } @INPROCEEDINGS{Nguyen2014, author = {Quang Vinh Nguyen and Simeon Simoff and Mao Lin Huang}, title = {Using visual cues on {DOITree} for visualizing large hierarchical data}, booktitle = {IV'14: Proceedings of the International Conference on Information Visualisation}, editor = {Ebad Banissi and Mark W. McK. Bannatyne and Francis T. Marchese and Muhammad Sarfraz and Anna Ursyn and Gilles Venturini and Theodor G. Wyeld and Urska Cvek and Marjan Trutschl and Georges Grinstein and Vladimir Geroimenko and Sarah Kenderdine and Fatma Bouali}, publisher = {IEEE Computer Society}, year = {2014}, pages = {1--6}, abstract = {This paper extends a previous work on node link tree visualization and interaction by providing visual clues on hidden structures. We adopt the effectiveness of DOI Tree, a multi-focal tree layout algorithm, for exploring large hierarchical structures. The advantages of visualization are its most familiar mapping for users, its capability on providing multiple focused nodes, and its dynamic rescaling of substructures to fit the available space. By providing various methods of topological previews of substructure including simple icon view, tree view and tree map view, we provide better understanding the topology of hidden branches.}, doi = {10.1109/IV.2014.21} } @ARTICLE{Nocaj2012, author = {Arlind Nocaj and Ulrik Brandes}, title = {Computing Voronoi Treemaps: Faster, Simpler, and Resolution-independent}, journal = {Computer Graphics Forum}, year = {2012}, volume = {31}, pages = {855--864}, number = {3}, abstract = {Voronoi treemaps represent hierarchies as nested polygons. We here show that, contrary to the apparent popular belief, utilization of an algorithm for weighted Voronoi diagrams is not only feasible, but also more efficient than previous low-resolution approximations, even when the latter are implemented on graphics hardware. More precisely, we propose an instantiation of Lloyd's method for centroidal Voronoi diagrams with Aurenhammer's algorithm for power diagrams that yields an algorithm running in O(n*logn) rather than Omega(n*n) time per iteration, with n the number of sites. We describe its implementation and present evidence that it is faster also in practice.}, doi = {10.1111/j.1467-8659.2012.03078.x} } @INPROCEEDINGS{ODonnell2006, author = {Richard O'Donnell and Alan Dix and Linden J. Ball}, title = {Exploring the {PieTree} for Representing Numerical Hierarchical Data}, pages = {239--254}, abstract = {This paper describes the first full implementation and evaluation of an area-based tree visualization known as the PieTree. The PieTree was first proposed in papers in 1998 and 2000 but has never been fully implemented and evaluated. Informal evaluation was used to enhance the usability of the PieTree and compare it with the more well-known TreeMap. A controlled experiment considered parallel views' effect on task performance time. There were substantial differences between kinds of tasks and in participants' styles of use. Whilst suggesting that further development of PieTrees is worthwhile the experiments underline the importance of careful task fit.}, doi = {10.1007/978-1-84628-664-3_18}, year = {2006}, booktitle = {People and Computers XX -- Engage: Proceedings of the Human Computer Interaction 2006}, editor = {Nick Bryan-Kinns and Ann Blandford and Paul Curzon and Laurence Nigay}, publisher = {Springer}, isbn = {9781846285882}, } @INPROCEEDINGS{Onak2008, author = {Krzysztof Onak and Anastasios Sidiropoulos}, title = {Circular Partitions with Applications to Visualization and Embeddings}, pages = {28--37}, abstract = {We introduce a hierarchical partitioning scheme of the Euclidean plane, called circular partitions. Such a partition consists of a hierarchy of convex polygons, each having small aspect ratio, and satisfying specified volume constraints. We apply these partitions to obtain a natural extension of the popular Treemap visualization method. Our proposed algorithm is not constrained in using only rectangles, and can achieve provably better guarantees on the aspect ratio of the constructed polygons. Under relaxed conditions, we can also construct circular partitions in higher-dimensional spaces. We use these relaxed partitions to obtain improved approximation algorithms for embedding ultrametrics into d-dimensional Euclidean space. In particular, we give a polylog(Delta)-approximation algorithm for embedding n-point ultrametrics into R^d with minimum distortion (Delta denotes the spread of the metric). The previously best-known approximation ratio for this problem was polynomial in n. This is the first algorithm for embedding a non-trivial family of weighted graph metrics into a space of constant dimension that achieves polylogarithmic approximation ratio.}, doi = {10.1145/1377676.1377683}, year = {2008}, booktitle = {SCG'08: Proceedings of the Symposium on Computational Geometry}, publisher = {ACM Press}, isbn = {9781605580715} } @INPROCEEDINGS{Ong2005, author = {TeongJoo Ong and John J. Leggett and Unil Yun}, title = {Visualizing Hierarchies and Collection Structures with Fractal Trees}, pages = {31--40}, abstract = {This paper addresses the need for better information access to digital library collections. Without proper visualization tools, organizational and structural information is often lost or suppressed by digital library interfaces. We discuss a 2D fractal tree visualization tool that can be used to more accurately present the structure, organization and interrelation of collection metadata.}, doi = {10.1109/ENC.2005.53}, year = {2005}, booktitle = {ENV'05: Proceedings of the Mexican International Conference on Computer Science}, editor = {Vladimir Estivill-Castro and J. Alfredo Sanchez}, publisher = {IEEE Computer Society}, isbn = {0769524540} } @ARTICLE{Opatrny2000, author = {Jaroslav Opatrny and Dominique Sotteau}, title = {Embeddings of complete binary trees into grids and extended grids with total vertex-congestion 1}, journal = {Discrete Applied Mathematics}, year = {2000}, volume = {98}, pages = {237--254}, number = {3}, abstract = {Let G and H be two simple, undirected graphs. An embedding of the graph G into the graph H is an injective mapping f from the vertices of G to the vertices of H, together with a mapping which assigns to each edge [u,v] of G a path between f(u) and f(v) in H. The grid M(r,s) is the graph whose vertex set is the set of pairs on nonnegative integers, {(i,j): 0<=i