Chart Representation Instruments NAM, Javis, Otter, H3Viewer - PowerPoint PPT Presentation

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Chart Representation Instruments NAM, Javis, Otter, H3Viewer PowerPoint Presentation
Chart Representation Instruments NAM, Javis, Otter, H3Viewer

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Chart Representation Instruments NAM, Javis, Otter, H3Viewer

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  1. Graph Visualization Tools NAM, Javis, Otter, H3Viewer Burton Filstrup

  2. Motivation • “Visual depictions of graphs and networks are external representations that exploit human visual processing to reduce the cognitive load of a task.” – Tamara Munzer • “A picture is worth a thousand words.” –Some Wise Guy

  3. Presentation Overview • Introduction to graph visualization • Tools • NAM/Javis • Otter • H3Viewer • Tool Comparison

  4. Visualization Tasks • Graph Layout • Interaction • Animation

  5. Graph Layout • Most useful layout algorithms are NP complete • Geographic Layout (Otter) • Hierarchical (Otter, H3Viewer) • Distortion-Based Layout (H3Viewer) • Topological Force-Directed Layout (NAM) • Gradient Descent, Simulated Annealing

  6. Interaction • Pan, zoom (All) • Rotate, translate, scale (Otter, H3Viewer) • Distort (H3Viewer) • Filter/color (Otter, H3Viewer) • Link to associated information (Otter, H3Viewer)

  7. Animation • Packet Flows (NAM, Javis) • Evolution

  8. NAM & Javis • Network animator • Integrated with NS • Developed at Berkeley • Source is available in C++ (NAM) or Java (Javis) • Input file is an NS trace • Demo

  9. NAM Input • Can define events for nodes, links, queues, packets, agents • Define a node event n -t * -s 69 -v circle -c grey -z 0.177110 • Define a link event l -t * -s 66 -d 67 -r 512000.000000 -D 0.010000 -c grey -o 236.6deg -l 0.012432

  10. Otter • 2-D graph visualization tool • Developed at CAIDA • Viewer source is available in Java • Input file is typically generated by a Perl script

  11. Otter Input • Can define nodes, links, paths • Nodes and links can be assigned to groups for filtering and coloring • Define node (w/position): N 3 32.715278 -117.156389 medusa.sdsc.edu(198.17.46.10) • Define link and associate a value with it: L 1 2 0 V 1 2 1'1

  12. H3Viewer • Scalable 3-D visualization tool • Developed by Tamara Munzer at Stanford • Library available in C++/OpenGL

  13. H3Viewer Input • Can define nodes, links • Nodes can be assigned to groups for filtering and coloring • A node definition’s location in the input file determines its position in the tree • Many H3Viewer features are currently available only through the API – MST policy, filtering, coloring…

  14. Graph Layout Comparison • NAM • Force-directed approach is not scalable • Poor manual layout support • Otter • Hierarchical layout is not scalable • Allows manual/geographic layout • Layout doesn’t work for general graphs • H3Viewer • Quasi-hierarchical layout is highly scalable • Layout doesn’t work for general graphs

  15. Interaction Comparison • NAM • Animates packet flows • Otter • Provides extensive navigation controls • Allows coloring/filtering of nodes & links • H3Viewer • Provides intuitive, effortless navigation • Allows coloring/filtering of nodes & links

  16. Ease of Use • NAM • Input files can be generated automatically by NS • Otter • Simple input file format • Easily customizable node values • H3Viewer • Complicated input files • Viewers are primarily implemented on IRIX • Well-defined library API

  17. References • NAM • http://imj.ucsb.edu/~ksarac/nstutorial/ns.html • Javis • ftp://cs.ucl.ac.uk/nets/src/jns/javis • Otter • http://www.caida.org/ • H3Viewer • http://graphics.stanford.edu/papers/h3/