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Visualizing Social Networks

Ryan Yee

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Plan

Introduction and terminology Vizster NodeTrix MatLink Applications to Multi-agent systems

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Terminology

Graph Model G = (V,E)

Graph Visualization Network / Node-Link Adjacency Matrix

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Node-Link

Vertices represented by nodes Edges represented by links

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Adjacency Matrix

Vertices represented by rows/columns Edges represented by cells

Edges are directed

A B C DABCD

A B C DABCD

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Node-link vs. Adjacency Matrix

Much easier to trace path in node-link Much easier to compare degree in matrix

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Problems…?

Social data is: Locally dense Traditional node-link excellent for overall structure

but less so for dense Adjacency excellent for dense structures but not

effective for overall structure

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Vizster: visualizing Online Social Networks (Heer, Boyd)

Visualization of friends Focuses on subset of known friends

Spring-based layout algorithm Spring strength based on vertex degree

Designed for finding clusters

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Vizster: 1 & 2 Degree

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Vizster: path finding

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Vizster: Focus

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Vizster: Searching

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Vizster: Xray Mode 1

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Vizster: Agglomerative Clustering

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Vizster: Xray Mode 2

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NodeTrix: A Hybrid Visualization of Social Networks (Henry, Fekete, McGuffin)

Overall layout is LinLog EnergyBased clustering

By default node-link visualization Interaction used to select subgraph and

transform into adjacency matrix Excellent for viewing clusters

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Nodetrix

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NodeTrix: Bridge Identification

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NodeTrix: Cliques

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MatLink: Enhanced Matrix Visualization for Analyzing Social Networks (Henry, Fekete)

Matlink is a adjacency matrix enhanced with links for the current path Nodes are the “row/columns”

Much easier to follow path Allows reordering of rows/columns:

find cliques easier

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Matlink: NL, MAT, MatLink

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Matlink

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Relation to Multi-agent systems

agents are sociable need to cooperate and communicate in order to

meet a goal Graph visualizations are more scalable than a

ladder visualization ladder visualization is messy for two to three

agents but ladder is used because it expresses time well

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Ladder vs. Node-Link

Alice Bob

what time is it?

5 o'clock

Thanks

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[1] J. Heer and D. Boyd. Vizster: Visualizing Online Social Networks. In Proceedings of the 2005 IEEE Symposium on Information Visualization, pages 33–40, 2005.

[2] N. Henry and J. Fekete. MatLink: Enhanced Matrix Visualization for Analyzing Social Networks. LECTURE NOTES IN COMPUTER SCIENCE, 4663:288, 2007.

[3] N. Henry, J.D. Fekete, and M.J. McGuffin. NodeTrix: A Hybrid Visualization of Social Networks. IEEE TRANSACTIONS ON VISUALIZATION AND COMPUTER GRAPHICS, pages 1302–1309, 2007.