pax

Hierarchical diagrams are well-suited for visualizing the structure and decomposition of complex systems. With the advent of UML 2.0, in particular the new composite structure diagram, hierarchical models have entered the modeling mainstream. However, the current tools poorly support hierarchical modeling and visualization. Simple explosive zooming is the most common means for navigating through hierarchies; some tools even visualize the complete hierarchy in a single large diagram. The line routing algorithms used by the current tools are poorly suited to this task: for example, they produce lines that run across nodes or overlap with other lines. In this paper, we present a novel algorithm for line routing in hierarchical models which, together with our previous work on node positioning, yields visualizations of hierarchical models that can easily be browsed and edited. In particular, our algorithm (i) produces an esthetically appealing layout, (ii) routes in real-time, and (iii) preserves the secondary notation of the diagrams as far as possible.

A Novel Algorithm for Line Routing in Hierarchical Diagrams

A Novel Algorithm for Line Routing in Hierarchical Diagrams

actions