Object-based directional query processing in spatial databases

Direction-based spatial relationships are critical in many domains, including geographic information systems (GIS) and image interpretation. They are also frequently used as selection conditions in spatial queries. In this paper, we explore the processing of object-based direction queries and propose a new open shape-based strategy (OSS). OSS models the direction region as an open shape and converts the processing of the direction predicates into the processing of topological operations between open shapes and closed geometry objects. The proposed strategy OSS makes it unnecessary to know the boundary of the embedding world and also eliminates the computation related to the world boundary. OSS reduces both I/O and CPU costs by greatly improving the filtering effectiveness. Our experimental evaluation shows that OSS consistently outperforms classical range query strategies (RQS) while the degree of performance improvement varies by several parameters. Experimental results also demonstrate that OSS is more scalable than RQS for large data sets.