PieVis: Interactive Graph Visualization Using a Rings-Based Tree Drawing Algorithm for Children and Crust Display for Parents

The quality of a graph drawing algorithm is often measured by its edge crossings, angular resolution, aspect ratio, and node labeling. Algorithms for drawing trees in general are segregated from algorithms for drawing graphs. In this paper we present a graph visualization system that uses a novel interconnection between a tree drawing algorithm and graph drawing techniques. First, the graph is transformed into a tree and nodes that have multiple parent connections within the graph are duplicated within the tree. While some of the connection information is lost during this transformation, the multiple connections can be regained by interactively displaying the details based on the degree of interest. We use an edgeless rings-based visualization which allows edge crossings and angular resolution issues to be eliminated and has a desirable aspect ratio of 1. Finally, a circular labeling method is used that provides user-friendly labels that do not overlap and clearly show node affiliation.