1. cs5984: Information Visualization Chris North
Trees 2
cs5984: Information Visualization
Chris North

2. 2 Approaches Connection (node & link) Containment (node in node)
Structure vs. attributes
Attributes only (multi-dimensional viz)
Structure only (1 attribute, e.g. name)
Structure + attributes A B C A B C

3. Containment Approach

4. Treemaps (Shneiderman)
Slice and Dice
Alternate horizontal and vertical cuts for levels
Node area  node attribute
Zoom onto nodes
Space-Filling
Structure + 3 attributes
Area, color, label

5. Treemaps

6. Treemaps
Balanced trees

7. Treemaps ~ 1000 nodes Quantitative attributes
Good combination of structure + attributes
For unbalanced trees, structure more difficult
Learning time: 20 min
Evaluation: major performance boost over outliner
Bad aspect ratios: long narrow rectangles
Large scale or deep causes solid black

8. Treemap Algorithm Calculate sizes:
Recurse to children
My size = sum children sizes
Draw Treemap (node, space, direction)
Draw node rectangle in space
Alternate direction
For each child:
Calculate child space as % of node space using size and direction
Draw Treemap (child, child space, direction)

9. Cushion Treemaps
Van Wijk

10. Squared Treemaps
Wattenberg
Van Wijk

11. Treemaps on the Web
Map of the Market:
People Map:
Coffee Map:

12. DiskMapper

13. Today
Stasko, “Sunburst”, web
Marcus, Marty

14. Assignment Spring Break! Read for Tues (Mar 13)
Beaudoin, “Cheops”, web
Satya, Sumithra
Furnas, “Fisheye View”, book pg 311

15. Projects Data Structure Viz Tool Data Structure Viz Evaluation
Biotech Viz
Network Traffic Viz
High-Dimensional Parameter Space Viz
Chat Log Viz
Web Snap
List Viz / Menu UI
Data Density and Distraction