1 / 29

Cone Trees and Collapsible Cylindrical Trees

Cone Trees and Collapsible Cylindrical Trees. Joshua Foster February 19, 2003. Papers. Cone Trees: Animated 3D Visualizations of Hierarchical Information Collapsible Cylindrical Trees: A Fast Hierarchical Navigation Technique. Goals of Cone Trees.

fabiano-knight
Download Presentation

Cone Trees and Collapsible Cylindrical Trees

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Cone Trees andCollapsible Cylindrical Trees Joshua Foster February 19, 2003

  2. Papers • Cone Trees: Animated 3D Visualizations of Hierarchical Information • Collapsible Cylindrical Trees: A Fast Hierarchical Navigation Technique

  3. Goals of Cone Trees • 3D visualization (display more information in same screen space) • Interactive animation (shifts some of the cognitive load to human visual perception system)

  4. 2D Aspect Ratio • Most real-life hierarchies tend to be broad, shallow, and unbalanced • 2D graph-building algorithms lay out a tree based on 2 parameters: • b – number of children per node (branching factor) • l – number of levels • Aspect ratio =

  5. Examples b = 2, l = 5, aspect ratio = 3.2 b = 3, l = 4, aspect ratio = 6.75

  6. Aspect Ratio vs. Number of Levels

  7. Aspect Ratio (cont’d) • Cone Tree aspect ratio is fixed at 4:3 (1.25) • Cone diameter and level height adjusted to accommodate • Side effect: Number of levels limited to 10

  8. User Perceptions • “Fisheye” view – selected objects are brighter, closer, and larger • Shadows provide depth information • Animation provides information about relationships

  9. User Interaction: Gardening • Gardening consists of two operations: • Pruning allows unwanted sublevels to be “cut” from the tree • Growing adds sublevels back in • Additional operations: • Prune Others: remove all the siblings of a selected node

  10. User Interaction (cont’d) • Changing Tree Structure: • User may drag a node (and its entire substructure) to a new place on the tree • Searching: • User may search nodes for text or properties • Search produces a relevancy bar at each node

  11. Applications • File browser • Organizational structure of a company • Company operating plan • Cone tree manipulation used to ‘restructure’ projects

  12. Problems? • Fixed aspect ratio imposes limits on tree size • Limits are roughly 1000 nodes, 10 levels, and maximum branching factor of 30 • Animation is more effective for unbalanced trees

  13. Papers • Cone Trees: Animated 3D Visualizations of Hierarchical Information • Collapsible Cylindrical Trees: A Fast Hierarchical Navigation Technique

  14. Goals of Collapsed Cylindrical Trees (CCT) • What they don’t do: • Visualize the entire tree structure • Provide insight into complex hierarchies • What they do do: • Allow quick navigation through hierarchies, find and perform an action on a specific node

  15. Motivation • Problems: • Simple GUI operations such as selecting menu items require long vertical mouse movements • Screen space may be limited (ex: cellphone displays) • Solution: • Map list items onto a rotating cylinder

  16. CCT Approach • Developed for webpage navigation • Individual nodes are important, not the entire tree • Tree navigation with other techniques: • Tree maps, cone trees, etc: too cluttered, hard to find individual node • Hyperbolic trees: node positions constantly changing, hard to build up “muscle memory”

  17. Example: Sitemap Navigation

  18. Layout • Every parent node is a cylinder, with the facets listing its child nodes • Children of the root node are shown in parallel • Child cylinders are nested • Endless cylinder concept

  19. User Interaction • Any node can be reached with a series of short mouse movements • Vertical mouse movements over a cylinder cause rotation • Mousing over a facet causes the child cylinder to appear

  20. Building “Muscle Memory” • Facets are always the same size • The selected cylinder is always the same width • Therefore, mouse movements are quickly memorized and become automatic

  21. Size Limitations • No more than 7 top-level nodes • Branching factor unlimited (due to endless cylinder concept) • Maximum number of nodes: • numrc * numfd = 7 * 206 = 4.48x108

  22. Applications • WWW sitemap navigation • Table of contents for Internet radio guides, manuals, tutorials, etc.

  23. User Perceptions • Fun to use • Comprehensible to persons with no 3D / visualization experience • Balanced: • More information than with traditional menus • Less information than with cone trees, treemaps, etc.

  24. Virtual Reality Markup Language (VRML) • Allows specification of 3D scenes through which the user can navigate • One .VRML file contains each object description • User can navigate through the scene: • “Walk” (6 degrees of freedom) • “Seek” (click an object and move closer toward it) • “Examine” (rotate or zoom the whole scene)

  25. Implementation • XML tree representation • Use Java to convert XML to VRML files and Javascript

  26. Performance • Acceptable frame rate with 300-node tree on a 750 MHz PC with mid-range video card • At most numrc + d - 1 cylinders shown at once

  27. Possible Enhancements • To increase number of root children: • Matrix-style layout • Toroidal cylinder arrangement

  28. Questions?

More Related