Reasoning Of Cardinal Direction Relations Based On MBR

With the developing of the spatial database technology, the applications of Qualitative spatial reasoning in the areas of geographic information system are more and more rich and clorful. As a part of the spatial reasoning, the researching for spatial relation's composing comes into being. Among this, a kind of problems has been paid much attention of, which we know a series of spatial object and cardinal direction relations between them, judge weither the net is consistency or not, and how to find a consistent scenario.Firstly, this paper introduce the direction relations reasoning which based on the spatial objects' minimum bounding rectangle, give the algorithm of consistency checking and advance the algorithm of finding a consistent scenario.Secondly, the models of MBR are crude approximations of the objects which can not describe the real direction relations of these objects. To overcome the limitations of these models so that improved reasoning can be performed, the coarse direction relation matrix is introduced. We use the direction relation matrix to describe the direction relations of these objects' MBRs. Under this circumstance we discuss all types of direction relations' composing theory, and give the method of computing the inverse direction relations based on matrix.Finally, we introduce the mothed to judge the convex relations of MBR, and give the algorithm to judge the convex relations of matrix. Integrating the mothed of composing and computing the inverse direction, we advanced the algorithm of consistency checking and finding a consistent scenario based on matrix.These research about cardinal direction relations reasoning, makefoundation for cardinal direction relations reasoning based on the real object.