A comparison of set-based and graph-based visualizations

The visualisation of hierarchical information sets has been a staple of Information Visualisation since the field came into being in the early 1990’s. However, at present, support for visualising the correlations between multiple, overlapping sets of hierarchical information has been lacking. This is despite the realisation that for certain tasks this information is as important as the information that forms the individual hierarchies. In response to this, we have produced two early visualisation prototypes, one based on a graph visualisation, and the other on a set-based metaphor, that endeavour to display such information in a readily perceived form to potential users. The science of botanical taxonomy is used as an example of a field where such a visualisation would be useful, and also as a resource for example information sets that the prototypes can act upon. Technical and perceptual issues involved in the design and implementation of both prototypes are discussed. Following this, informal user testing on both prototypes is described, which utilised user observation techniques to elicit qualitative feedback from the taxonomists. These findings are then used to emphasise the shortcomings and advantages of each prototype, and from these probable issues for future prototyping and development are drawn