Standard for Spatial Relations in SDTS

Toward a Standard for Spatial Relations in SDTS and Geographic Information Systems

David Mark, Max Egenhofer, and A. Rashid Shariff

Abstract

SDTS, the U.S. Spatial Data Transfer Standard, provides methods for describing topology, metrics, attributes, and categorizations of individual spatial objects and the entities they represent. It does not yet, however, include methods for formally describing spatial relations. Addition of formal spatial relation definitions to SDTS requires a suite of spatial relations with sufficient expressive power to capture the same distinctions in spatial relations that people make when reasoning about or describing spatial information. Recent evidence suggests that a formal model of spatial relations called the 9-intersection provides a sound basis for characterizing spatial relation. However, spatial relations meaningful to end users often seem to be compound relations, aggregates of two or more of the 9-intersection primitives. In addition to formal definitions, SDTS and similar standards should include formal definitions and names for selected compound spatial relations. Relevant completed research is reviewed and an agenda for filling out the details is outlined.