Edge concentration: a method for clustering directed graphs

Abstract

The display of a directed graph is a commonly used visual aid for representing relationships. However, some graphs contain so many edges that their display by traditional graph layout algorithms is virtually impossible because of the overwhelming number of crossings. Graphs representing large software systems and their configurations are particularly prone to this problem. Examples of such graphs include: graphs depicting a system's configuration, call graphs, graphs depicting import and export relationships between modules, and graphs depicting the “includes” relation among a system's source files.