The Objects Interaction Matrix for Modeling Cardinal Directions in Spatial Databases

Besides topological relations and approximate relations, cardinal directions have turned out to be an important class of qualitative spatial relations. In spatial databases and GIS they are frequently used as selection criteria in spatial queries. But the available models of cardinal relations suffer from a number of problems like the unequal treatment of the two spatial objects as arguments of a cardinal direction relation, the use of too coarse approximations of the two spatial operand objects in terms of single representative points or minimum bounding rectangles, the lacking property of converseness of the cardinal directions computed, the partial restriction and limited applicability to simple spatial objects only, and the computation of incorrect results in some cases.