Implementation of a Perfect Rewriting Algorithm for Ontology Based Query Answering over Spatial Databases
Providing reasoning in GIS domains is a demanding task due to the size of the data that are stored in secondary memory. This is also the case for query answering over spatio-thematic ontologies which act as an interface to the GIS data and filter unintended models. Solving this problem by compiling the ontology into an SQL query works only in those cases in which such a compilation, first-order logic (FOL) rewritability, is theoretically possible. Combining lightweight description logics like DL-Lite that are tailored towards FOL-rewritability with spatial calculi like the region connection calculus in a näıve way can prohibit FOL-rewritability. But if assumption on the completeness and the consistency of the spatial data are made and the combination is done in a controlled way combinations of DL-Lite and the region connection calculus result that are sufficiently expressive to model GIS data and at the same time allow for computationally feasible query answering.