COMPOSITE REGIONS IN TOPOLOGICAL QUERIES

Spatial data are at the core of many scientific information systems. T he design of suitable query languages for spatial data retrieval and a nalysis is still an issue on the cutting edge of research. The primary requirement of these languages is to support spatial operators. Unfor tunately, current systems support only simplified abstractions of geog raphic objects based on simple regions which are usually not sufficien t to deal with the complexity of the geographic reality. Composite reg ions, which are regions made up of several components, are necessary t o overcome those limits. The paper introduces a two-level formal model suitable for representing topological relationships among composite r egions. The contribution gives the needed formal background for adding composite regions inside a spatial query language with the purpose of answering topological queries on complex geographic objects.