1. Information Visualization: Trees Chris North cs3724: HCI

2. Info Visualization Review Multi-dimensional data vis Navigation strategies

3. Trees (Hierarchies) What is a tree? DAG, one parent per node items (can have attributes) + structure Data structure: parent ptr, array of children, LM child+RS Size: #nodes = b height ResultSet -> Tree? categorical Parent ptr Path name

4. Examples Example trees: book libraries, folders, family trees, threaded msgs NCAA march madness!!!! Aisles, websites, org charts Tasks: search, drill down, browsings Structural analysis, parents, children, Least common ancestor

5. 2 Approaches Connection node & link E.g. TreeView widget Containment node in node E.g. Venn diagram A CB A BC

6. Detail Only Dos: tree Whats the problem?

7. TreeView Widget Good for directed search tasks Good for text labeled nodes Not good for learning structure No attributes Apx 50 items visible Lose path to root for deep nodes Scroll bar! Error rate high Fitt’s Law? Too many small distant things

8. Mac Finder

9. Overview+Detail Maryland

10. Focus+Context Hyperbolic Tree (star tree) Radial; shrink with distance to center Drag to navigate Scalability? Xerox PARC, Inxight http://startree.inxight.com/

11. Miniaturization Disk Tree Xerox PARC

12. 3D ConeTrees Rotate subtrees Pro: Con: Xerox PARC

13. Ugh!

14. FSN SGI file system navigator Jurassic Park

15. 2 Approaches Connection node & link E.g. TreeView widget Containment node in node E.g. Venn diagram A CB A BC

16. Zooming TreeMaps Slice and Dice, space filling Node size & color encodes data attribute Zoom on subtrees Good for fixed-height trees Scalability? Maryland http://www.cs.umd.edu/hcil/treemap3/

17. “Squarified” TreeMap http://www.research.microsoft.com/~masmith/all_map.jpg

18. Cushion TreeMaps Free file directory browser Van Wijk http://www.win.tue.nl/sequoiaview/ Map of the Market http://www.smartmoney.com/marketmap/

19. Radial Containment SunBurst Radial slicing Animated zooming Focus+Context Georgia Tech

20. Sunburst vs. Treemap + Faster learning time: like pie chart + Details outward, instead of inward + Focus+context zooming - Not space filling - More space used by non-leaves All leaves on 1-D space, perimeter Treemap: 2-D space for leaves - Smaller scalability?

21. Multiple Foci? Focus on 2 distant regions simultaneously Microsoft Research