Approaches to the Representation of Qualitative Spatial Re Lationships for Geographic Databases

Qualitative spatial reasoning is important for many spatial in formation systems including GISs It is based on the manipulation of qual itative spatial relationships and is used to infer spatial relationships which are not stored explicitly in the Geographic DataBase GDB to answer spa tial queries given partial spatial knowledge and to maintain the consistency of the GDB This paper compares the basic approaches developed for ex pressing qualitative topological orientation and direction relationships An extension of one of the classi ed approaches is then used for the represen tation of directional relationships north south east etc between objects of arbitrary shapes and for the representation of ow direction relationships topological relationships between objects carrying ow e g road segments utility networks etc as required within a GIS