Representing and reasoning over topological relations in OWL

Representing topological information for the Semantic Web often involves qualitative defined natural language terms such as "Into" or "Overlapping". This can be the case when exact coordinates of spatial regions are not available, they are incomplete or unreliable. Topological spatial relations are the most important aspect of spatial representation and reasoning, thus embedding such relations into an ontology along with their semantics as expressed using reasoning rules is an important issue. In this work we propose a representation of RCC-5 topological relations using OWL object properties and axioms, combined with reasoning rules expressed using SWRL embedded into the ontology. Three alternative representations are proposed and compared: the first is based on a straightforward implementation of the path consistency method for spatial reasoning, the second is an optimized version of the path consistency based representation implemented using an alternative representation of the topological equality relation and the third is based on the decomposition of RCC-5 relations to simpler ones. To the best of our knowledge this is the first work dealing with topological RCC-5 relations representation for the Semantic Web. In addition, our work improves the performance of topological RCC-8 relations reasoning when the best method, in terms of reasoning time, for RCC-5 relations is applied over RCC-8 relations.