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SIMS 247: Information Visualization and Presentationjeffrey heer

Tree VisualizationOct 26, 2005 

 

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today

• administrivia• tree visualization• design exercise

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administrivia

• How are project proposals coming along?• If you have questions, concerns, or are seeking

advice, come to my office hours!!– Today, 1-2:30pm - 210 South Hall– Appointments also possible

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Graphs and Trees

• Graphs: – Representations of structured, connected data– Consist of a set of nodes (data) and a set of edges

(relations)

• Trees: – Graphs with a specific structure

• connected graph with n-1 edges

– Representations of data with natural hierarchy– Nodes are either parents or children

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Tree Visualization

• File Hierarchyin computer

• Need to navigate through the hierarchy to find a particular file

• Two common problems: “Where am I?” and “Where is the file that I am looking for?”

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Tree Visualization

• Organizational Chart

http://www.cs.umd.edu/hcil/spacetree/

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Tree Visualization• Tournaments

taken from “To Draw A Tree” by Pat Hanrahan

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Tree Visualization

• Family Trees

taken from “To Draw A Tree” by Pat Hanrahan

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Tree Visualization• Family Trees

taken from “To Draw A Tree” by Pat Hanrahan

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Tree Visualization• Evolutionary

Trees

taken from “To Draw A Tree” by Pat Hanrahan

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Tree Visualization

• Evolutionary Trees

taken from “To Draw A Tree” by Pat Hanrahan

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Tree Visualization

• Assembly Instructions

taken from “To Draw A Tree” by Pat Hanrahan

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Tree Visualization Approaches• Node-Link Diagrams

– Reingold-Tilford Layout– Radial Layout– Indented Layout– Cone Trees & Balloon Trees– Hyperbolic Trees

• Enclosure Diagrams– TreeMaps– Voronoi TreeMaps– Jigsaw Maps

• Alternative Approaches– Icicle Trees– Sunburst Diagrams– Cascaded Lists

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Top-down layout

Uses separate dimensions for breadth and depth

breadth --> width depth --> height

Reingold-Tilford Layout

tidier drawing of trees - reingold, tilford

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Radial Layout

Places children on increasing larger radii

A top-down layout converted into polar co-ordinates

breadth --> angle depth --> radius

gnutellavision – yee, fisher, dhamija, hearst

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Indented Layout

Places all items along vertically spaced rows

Uses indentation to show parent child relationships

Breadth and depth end up fighting for space resources

breadth --> height, locality depth --> height, indentation

microsoft file explorer

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Cone Trees

Top-down tree layout in three dimensions

Shadows provide 2D structure

Can also make “Balloon Trees” – 2D version of ConeTree

cone tree – robertson, mackinlay, and card

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Balloon Trees

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

• flattened cone trees

herman, melancon, and marshall

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Hyperbolic Trees

Places nodes using hyperbolic geometry

This is then projected into “normal” space

hyperbolic tree – lamping, raoh3 viewer – tamara munzner

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TreeMaps

Space-filling technique that divides space recursively

Segments space according to ‘size’ of children nodes

map of the market – wattenberg / smartmoney.com

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Voronoi TreeMaps

• TreeMaps that divide space using arbitrary polygons based on Voronoi tesselations.

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

voronoi treemaps - balzer and deussen

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Jigsaw Maps

• Space-filling technique from Martin Wattenberg - a mathematical experiment at trying to achieve a “perfect” layout.

• Uses the mathematics of space-filling curves.

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

jigsaw maps - martin wattenberg

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Icicle Trees

• Edges implied by adjacency and spatial relationship.

icicle tree in the infovis toolkit - jean-daniel fekete

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Sunburst Diagrams• Radial version of icicle trees.

sunburst diagram - john stasko

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Cascaded Lists

• Display one selected group of silbings at a time• Mac OS X File System Browser

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

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More advanced trees…• We can augment the approaches we’ve seen

so far with additional visualization and interaction techniques. Some examples:

• Degree-of-Interest Trees / SpaceTree– top-down node-link diagrams with focus+context

• Elastic Hierarchies– node-link diagrams crossed with treemaps

• Dual Trees– bi-directional top-down node-link diagrams– developed for genealogical graphs

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degree-of-interest trees

doitrees - heer, card

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elastic hierarchies

• hybrid of node-link diagrams and treemaps

elastic hierarchies - zhao, mcguffin, chignell

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dual-trees

• a bidirectional tree visualization designed for navigating genealogical graphs (family “trees”)

QuickTime™ and aTIFF (LZW) decompressor

are needed to see this picture.

dual-trees - mcguffin, balakrishnan

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So what technique to use?• A cautionary tale:

– CHI Browse-off and evaluation of the hyperbolic tree– What makes the difference: the car or the driver?

• Reading– People read faster by scanning in lines (not arcs!)

• Convention– Does your application domain have established

conventions? How can you leverage or augment those?

• Designs with multiple visual components– How much screen real-estate do you give the tree?– (Sometimes that indented tree works the best!)

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Design Exercise

• Brainstorm new visualizations for family “trees”• Choose an aspect *NOT* covered by current designs• Here are some of the complications to consider:

– People as individuals / Couples as reproductive units– Ordering by Generation vs. Time– Divorce/Death/Remarriage– Polygamy– Incest (!)– Social vs. Biological lineages?

• Think of important questions a visualization should answer, use them to motivate the design– Are two people related? In how many ways?

• Work in groups of 3 or more. You will be asked to briefly present your ideas to the class on Monday!

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