Supporting Direction Relations in Spatial Database systems

Abstract

Abstract: Direction relations (e.g., north, northeast) constitute an important class of user queries in Spatial Databases and Geographic Information Systems. However, little work has been done on the formalization and efficient processing of such relations. In this paper we define direction relations between two-dimensional objects and we show how they can be efficiently retrieved in existing DBMSs using alternative indexing methods. We also propose modifications of the traditional techniques that facilitate efficiency for several types of queries. Although for our experiments we use a small set of representative relations motivated by geographic applications, the results of this paper are directly applicable to any type of direction relations that may arise in different application domains.