The retrieval of direction relations using R-trees

Abstract

R-trees and related structures, like R+-trees and R*- trees, have been used to answer queries involving topological information about objects represented by their minimum bounding rectangles (MBRs). This paper describes how the R-tree method can be used for the storage and retrieval of direction relations. Direction relations deal with order in space, as for instance, left, above, north, southeast etc. In this paper we define direction relations between points and extend the definitions to relations between objects. Then we present our tests regarding the retrieval of direction relations between objects using R-trees and discuss the representational properties of MBR approximations with respect to directions in 2D space.