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This document provides an in-depth analysis of various tree visualization approaches including connection, containment, and methods for visualizing structure versus attributes. It specifically focuses on treemaps, discussing techniques like slice and dice, balanced trees, and space-filling representations. The evaluation of treemaps highlights their efficiency in representing quantitative attributes and combines structures with multiple attributes for enhanced clarity. The document also references tools and resources for practical application of these visualization methods, including links to relevant web projects.
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Trees 2 cs5984: Information Visualization Chris North
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
Treemaps (Shneiderman) • Slice and Dice • Alternate horizontal andvertical cuts for levels • Node area node attribute • Zoom onto nodes • Space-Filling • Structure + 3 attributes • Area, color, label
Treemaps Balanced trees
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
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 childspace as % of node space using size and direction • Draw Treemap (child, child space, direction)
Cushion Treemaps • Van Wijk
Squared Treemaps • Wattenberg • Van Wijk
Treemaps on the Web • Map of the Market: http://www.smartmoney.com/marketmap/ • People Map: http://www.truepeers.com/ • Coffee Map: http://www.peets.com/tast/11/coffee_selector.asp
DiskMapper • http://www.miclog.com/dmdesc.htm
Today • Stasko, “Sunburst”, web • Marcus, Marty
Assignment • Spring Break! • Read for Tues (Mar 13) • Beaudoin, “Cheops”, web • Satya, Sumithra • Furnas, “Fisheye View”, book pg 311
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