Graph Drawing Aesthetics and the Comprehension of UML Class Diagrams: An Empirical Study

Many existing automatic graph layout algorithms are unrelated to any particular semantic domain. Designers of such algorithms tend to conform to layout aesthetics, and claim that by doing so, the resultant diagram is easy to understand. Few algorithms are designed for a specific domain, and there is no guarantee that the aesthetics used for generic layout algorithms will be useful for the visualisation of domain-specific diagrams (for example, visual programs, or entity-relationship diagrams). This paper describes a study which aimed to identify the most important aesthetics for the automatic layout of UML class diagrams from a human comprehension point of view. The results suggest that for specific domains, the actual semantics of the given graph may need to be considered before an appropriate graph drawing can be produced.