We present a first treatment dealing with the semantics of visual spatial query languages for geographic information systems using a suitable description logic. This decidable space logic is described and its usefulness for geographic information systems is exemplified. The logic supports the specification of a semantics, reasoning about query subsumption and about applying default knowledge. 1 Introduction For accessing spatial databases or geographic information systems (GIS), di#erent query specification techniques have been proposed. For instance, the visual spatial query system VISCO developed in our group [9, 13] can be used to query a spatial database (GIS) in a visual way. In contrast to conventional textual query systems the user is not required to learn a complicated textual query language in order to e#ectively use an information system. Users can query the database by drawing diagrammatic representations of what is to be retrieved from the spatial information system....

We present a first treatment dealing with the semantics of visual spatial query languages for geographic information systems using a suitable description logic. This decidable space logic is described and its usefulness for geographic information systems is exemplified. The logic supports the specification of a semantics, reasoning about query subsumption and about applying default knowledge. 1