This document discusses network graphs and how to visualize them using Gephi. It defines graphs as mathematical concepts composed of nodes and edges. Nodes represent actors or entities, while edges show relationships between nodes. Edges can be directed, showing a one-way relationship, or undirected, showing a mutual relationship. Centrality measures how connected nodes are based on the number of edges. The document also discusses other measures like modularity and formatting data using CSV files with node and edge tables.

1. 1
Network Graphs
Visualizing with Gephi

2. 2
Graphs
 Mathematical concept
 Composed of two elements
 Nodes
 Edges

3. 3
Nodes
 Actors, entities
 Expressed as points on the graph
 Anchors for ...

4. 4
Edges
 Express a relationship between nodes
 Represented as a line between two nodes

5. 5
Two types of edges
 Directed
 One-way relationship
 Author → Book
 Graph composed of
only directed edges is a
“force-directed graph”
 Undirected
 Expresses a simple
relationship
 Mutual applied equally to
both nodes
 Friend ↔ Friend

6. 6
Edges & Centrality
 Centrality is a measure of connected-ness
 i.e. numbers of edges for each node
 Centrality measures can be quite exotic
 Various scopes of centrality

7. 7
Other measures
 Modularity
 Insular / densely connected communities
 In-degree / Out-degree
 Only applies to directed graphs
 How many ways can you “travel” to Node A from any other node?

8. 8
Formatting data
 CSV – Comma Separated Values

9. 9
Formatting data
 Edge table
 Source
 Target
 Weight
 Node table
 ID
 Label
 Attributes

10. 10
Data!
http://myweb.fsu.edu/mmiguez/doc/gephiData01.csv
http://myweb.fsu.edu/mmiguez/doc/gephiData02.csv