1. Interactive Navigation of Large Graphs and Networks Tamara Munzner Stanford University Graphics Group, CS Dept

2. Overview zCognitive psychology wish list zInfoVis problems zGraph drawing examples ygraph == network ynode-link as in graph theory ynot bar charts

3. Interaction zFluid interaction is hallmark of modern CG zCan create non-real environments zExample: navigation yRW: rigid motion across fixed terrain yCG: distortion, warping of structure/space xwhen (if ever) is this useful?

4. Wanted: Prescriptive Advice zHave for static 2D yGestalt, Bertin, Mackinlay, etc zMy wish list: ydynamic, spatial xwhen are distortion (focus+context) systems useful?

5. Process z[Distill domain knowledge into explicit problem statement] zFind visual technique(s) to help solve problem with preattentive processing zFeedback: is system solving problem? yAre they using it? yDoes it help?

6. CP wish list, cont. zAnalyze what’s good when: yTease apart complex visual metaphors into constituent low-level components yConceptual framework, user studies zBackmapping: once know what it’s good for, what other domains can be abstracted into this problem?

7. Problems zScalability yreal-world datasets consistently outstrip tools zEfficacy ylack of rigor in evaluating viz systems zNovelty ycreating new visual metaphors is difficult zAdoption yend user buy-in

8. Graph drawing: traditional zStatic++ yinteractivity not inherent ypan/scroll/zoom substitute for really big paper zDoes not scale ysmall (dozens, hundreds, maybe thousands) yaggregation/abstraction of large datasets xgreat for expository, poor for exploratory zspring-force, circular, hierarchical, etc ydot, daVinci, Tom Sawyer, etc

9. Three Interactive Systems zGeographic: Planet Multicast zHyperbolic: H3/H3Viewer zImportance gradient: Constellation

10. Geographic: Planet Multicast zTarget users: Mbone maintainers zTechnique: arcs on globe [Eick95] zTask: identify long-haul misconfigurations

11. Planet Multicast excerpt zInteraction techniques: yclick on arc for tunnel info yrotate globe around center x selective occlusion yrotate around point on surface xhorizon view disambiguates

12. PM analysis zVisual popout: ylong-distance links ycluttered tunnel topology zLiteral & natural: no explanations needed zFiltering: intercity not intracity y4000 -> 700 yhemisphere occlusion

13. PM efficacy zgeog distance only approximates bottleneck sources yideal data uncollectable yfew false positives, many false negatives zIP address -> lat/lon mapping infeasible zAdoption: ymaintainer coauthor during development zDoes it help? yAnecdotal

14. Hyperbolic: H3Viewer zTarget users: webmasters, gawkers zTechnique: yuses 3D hyperbolic space for recursive hemispherical layout and navigation yspanning tree backbone with nontree links drawn on demand yguaranteed frame rate drawing algorithm zTask: show context of surfing choices

15. H3Viewer video

16. H3 analysis zVisual popout: ysubtree clusters zFiltering: yspanning tree in default case zScalability: y>100,000 nodes

17. H3 Efficacy zAdoption: yShips with SGI Irix 6.2-6.5 xminor user testing xuser feedback in the wild extremely minimal yPD code, other developers xnetworking, genetic algorithms zDoes it help? yReal user study prelim results promising

18. Importance Gradient: Constellation zTarget users: two linguists at MSR zTechniques: ycustom spatial layout, horiz gradient ycareful use of HSV to minimize clutter impact zTask: debug semantic network creation yfind implausible computed paths

19. Constellation video

20. Constellation analysis zVisual popout: yhotspots, highlighted structures zFiltering: none ydesign principle of avoiding hidden state zAdoption: TBD ystill under development ypros and cons of tiny user community

21. Conclusion zKey problem in the field: yEvaluating efficacy yScalability zExploration of the design space ythree quite different GD systems

22. Acknowledgements zPlanet Multicast: yEric Hoffman, Kim Claffy, Bill Fenner zSite Manager: yGreg Ferguson, Alan Braverman, Ken Kershner zConstellation: yFrancois Guimbretiere, George Robertson zAdvisor: Pat Hanrahan

23. More info zhttp://graphics.stanford.edu/~munzner ypapers ytalks ysoftware