A Reusable 3D Visualization Component for the Semantic Web

Ontology visualization and exploration is not a trivial task as many issues can affect the effectiveness of interactions. As ontologies are, in the general case, quite connected graphs where concepts are the nodes and semantic relationships the edges, the problems include space allocation, edge superposition, scene over-crowding, etc. In this paper we propose a solution for the visualization and the exploration of ontologies using a 3-dimensional space, where information is represented on a 3D view-port enriched by visual cues. Our visualization tool aims at tackling representation issues of ontology models (as space allocation or the completeness and read-ability of displayed information) by adopting different views, at different granularities, in order to grant a constant navigability of the rendered model. Each provided view represents semantic information according to a different, task-based visualization paradigm, at a suitable level of detail. Besides being primarily implemented as a Protege plug-in, the proposed solution (named OntoSphere3D) is designed to be a reusable visualization component within Semantic Web applications; in fact, every scene can be exploited as a standalone facility that provides access to ontological data through an intuitive and appealing. 3D interface. A case-study, is presented, where re-usability is demonstrated by integrating the OntoSphere3D visualization inside an Eclipse-based tool for Web Service design (called Web Services Design Tool) developed by some of the authors in the context of another research project