RADIAL EDGE SPLATTING FOR VISUALIZING DYNAMIC DIRECTED GRAPHS

University of TrierKeywords: Graph visualization, node-link diagrams, radial layout, splattingAbstract: We describe and discuss a novel radial version of a scalable dynamic graph visualization. The radial layoutencodes dynamic directed graphs on narrow rings of a circle. The temporal evolution of the graph is mapped torings that grow outward from the center of the circle. Graph vertices are placed equidistantly at the borderlinesof each ring. Graph edges are displayed as curved lines starting from a source on the inner borderline of thering and pointing to a target on the outer borderline. To better perceive link directions and structures of largedatasets, visual clutter is reduced by exploiting an edge splatting approach that generates density elds of thedisplayed edges. The radial layout emphasizes newer graphs, displayed in the larger, outer parts of the circle.As a benet, edge lengths are reduced in comparison to the non-radial visualization. Moreover, the radiallayout guarantees the symmetry of the visualization under shifting of vertices. We illustrate the usefulness ofthe diagrams by applying them to call graph data of the open source software project Cobertura.