Techniques for the Refinement of Orthogonal Graph Drawings

Current orthogonal graph drawing algorithms produce drawings which are generally good. However, many times the quality of orthogonal drawings can be significantly improved with a postprocessing technique, called refinement, which improves aesthetic qualities of a drawing such as area, bends, crossings, and total edge length. Refinement is separate from layout and works by analyzing and then fine-tuning the existing drawing in an efficient manner. In this paper we define the problem and goals of orthogonal drawing refinement, review measures of a graph drawing’s quality, and introduce a methodology which efficiently refines any orthogonal graph drawing. We have implemented our techniques in C++ and conducted experiments over a set of drawings from five well known orthogonal drawing systems. Experimental analysis shows our techniques to produce an average 37% improvement in area, 23% in bends, 25% in crossings, and 37% in total edge length.