On Coherent Indented Tree Visualization of RDF Graphs

Indented tree has been widely used to organize information and visualize graph-structured data like RDF graphs. Given a starting resource in a cyclic RDF graph as root, there are different ways of transforming the graph into a tree representation to be visualized as an indented tree. It would be interesting to investigate whether and how these different representations influence the user’s browsing experience. In this paper, we address this issue from the coherence aspect (i.e. the percentage of non-reversed edges) of tree representation. We aim to smooth the user’s reading experience by visualizing an optimal indented tree in the sense of featuring the fewest reversed edges, which often cause confusion and interrupt the user’s cognitive process due to lack of a general, effective way of presentation. To achieve this, we propose a two-step approach that is proven to generate such an optimal tree representation for a given RDF graph and a specified starting resource. We also empirically show the difference in coherence between tree representations of real-world RDF graphs generated by our approach and two popular baseline approaches. These different tree representations lead to a significance difference in user experience in our preliminary user study, which reports a notable degree of dependence between coherence and user experience.