SemaSun: Visualization of Semantic Knowledge based on an improved Sunburst Visualization Metaphor

Ontologies have become an established data model for conceptualizing knowledge entities and describing semantic relationships between them. They are used to model the concepts of specific domains and are widespread in the areas of the semantic web, digital libraries and multimedia database management. To gain the most possible benefit from this data model, it is important to offer adequate visualizations, so that users can easily acquire the knowledge. Most ontology visualization techniques are based on hierarchical or graph-based visualization metaphors. This may result in information-loss, visual clutter, cognitive overload or context-loss. In this paper we describe a new approach of ontology visualization technique called SemaSun that is based on the sunburst visualization metaphor. We improved this metaphor, which is naturally designed for displaying hierarchical data, to the tasks of displaying multiple inheritance and semantic relations. This approach also offers incremental ontology exploring to reduce the cognitive load without losing the informational context.