Hierarchical Edge Bundling

A compound graph is a frequently encountered type of data set. Relations are given between items, and a hierarchy is defined on the items as well. Hierarchical Edge Bundling is a new method for visualizing such compound graphs. Our approach is based on visually bundling the adjacency edges, i.e., non-hierarchical edges, together. We realize this as follows. We assume that the hierarchy is shown via a standard tree visualization method. Next, we bend each adjacency edge, modeled as a B-spline curve, toward the polyline defined by the path via the inclusion edges from one node to another. This hierarchical bundling reduces visual clutter and also visualizes implicit adjacency edges between parent nodes that are the result of explicit adjacency edges between their respective child nodes. Furthermore, hierarchical edge bundling is a generic method which can be used in conjunction with existing tree visualization techniques.

Sample Visualizations

../_images/hiearchical-edge-bundling.png

Hierarchical edge bundling of SaltStack services and their relations (cca 100 nodes)