Spatial Database Querying with Logic Languages

Several d&rent data structures, generally grouped in Raster and Vectors representation models, are used to store images and all hinds of spatial data. One solution, for a spatial data manipulation language to be independent of the storage model, is to base the language on the spatial relations of objects (i.e. the positions of objects relative to each other). This paper proposes a logic intermediate language allowing a declarative querying. We show that this language can be easily computed by a procedural execution using a small set of operators. This language enables expression of direction and topological spatial relations and ensures a physical data independence and the processing can benefit from spatial access methods. The language is composed of two complementary sub-languages. The first one uses an object approximate and results in the selection of a set of candidate objects, which are investigated more in detail using the second one.