Visualizing dynamic directed and weighted graphs with an additional hierarchical organization of the graph vertices is a challenging task. Many data dimensions have to be represented at the same time:

• the graph vertices
• the adjacency edges induced by the graph
• the weights of the adjacency edges
• the inclusion edges induced by the hierarchy
• the evolution of the graph over time

Traditional approaches use a time-to-time mapping and show the time-varying graph data as animated sequences of node-link diagrams. Though this visualization strategy is very intuitive it also has some drawbacks:

• if the graphs are very dense, i.e. have many edges, visual clutter occurs caused by many edge crossings
• animation leads to cognitive efforts for a viewer to preserve his mental map
• sophisticated layout algorithms are needed to circumwent the two former mentioned problems that have a high run time complexity