Presentation on theme: "Trees and Cushions Jack van Wijk Eindhoven University of Technology Treemap Workshop, May 31, 2001 HCIL, University of Maryland."— Presentation transcript:
Trees and Cushions Jack van Wijk Eindhoven University of Technology Treemap Workshop, May 31, 2001 HCIL, University of Maryland
InfoVis at Eindhoven l Started 1998 l Focus: Trees and graphs Large data sets Use of computer graphics knowledge (textures, geometry, shading) to generate more effective visualizations
Trees (T) and Cushions (C) l T+C: Cushion treemaps (InfoVis’99) l T+C: Squarified treemaps (Vissym’00) l C: Voronoi diagrams (Vissym’01) l C: Enridged contour maps (Vis’01) l T: Botanical vis (InfoVis’01) l What next?
Cushion Treemaps Visualization of Hierarchical Information Jarke J. van Wijk Huub van de Wetering Eindhoven University of Technology IEEE InfoVis’99
Insight in structure of large trees l Why is my disk full? l What is our product portfolio? l How is this university organized? Fuzzy questions: Visualization needed
How to emphasize structure? l Color? l Linewidth? l Nesting? l Shading? Use shaded geometric model!
Ridges for more insight Binary tree Ridges
Ridge + rotated ridge = cushion += z = ax + bx + cy + dy + e 2 2
H = 0.75 level
H = 0.50 level
Demo May : 45,000 downloads
Squarified Treemaps Mark Bruls Kees Huizing Jarke J. van Wijk Eindhoven University of Technology Vissym’00, Amsterdam
l hard to compare sizes l hard to point at l waste of pixels l inaccurate size Thin rectangles (small leaves high in hierarchy e.g.,.cshrc)
How to avoid thin rectangles? (emphasize structure by other means) drop the single direction layout
Squarification algorithm 1. Start placing recs in one row 2. stop when aspect ratio stops getting better 3. repeat with remaining area and recs Recursive per level (just like standard treemap algorithm)
Back to Trees: Botanical Visualization of Huge Hierarchies Ernst Kleiberg, Huub van de Wetering, Jarke van Wijk InfoVis’01, San Diego
Idea l Botanical trees are easy to understand, yet contain a lot of branches and leaves l Can we use ideas from botanical modeling for InfoVis?
Strand model (Holton, 1994) l Mimics vascular system l Each leaf is connected to one strand l Branch = bundle of strands l Rules define when a branch is split First try: l Each directory is a branch l Each file is a leaf
Three problems l Continuing branches are hard to see l Long, thin branches emerge l Leaves are messy
Smoothed continuing branches
Contract long branches
Files: Phi-balls (Lintermann,99) One big file Many small files
Botanical modeling l Compact, natural visualization l Phyllotaxis = magic! l Many treasures to be discovered l Usability? l Botanical treemaps?
My treemap to-do list l Non-rectangular shapes/subdivisions circles, polygons? l Multivariate data color, texture? l Applications genealogy, data mining? l Evaluation