In this paper we consider various spatial relationships that are of general interest for retrieving data from multimedia databases. We present a unified representation of spatial objects for both topological and directional relations. Such a representation is based on Allen's temporal interval algebra. We also present a set of spatial inference rules, which allow us to make heterogeneous spatial relation deductions from existing directional and topological relations. For example, if we know A north of B, B overlap with C, and C north of D, then we derive A above D. Since all the rules are propositional Horn clauses, they can be easily integrated into any multimedia database by using either a simple inference engine or a lookup table.