A new directional query method for polygon dataset in spatial database

Abstract

Directional query is critical in many domains, especially in geographic information systems (GIS), which are also frequently used as selection conditions in spatial queries. In this paper, we explore the processing of directional queries based on MRD-tree and open shape model. The interior node of MRD-tree contains not only index entries but also data entries, where the data entry contains the pointer of actual spatial object in disk, the maximum boundary rectangle (MBR) and the maximum enclosed circle (MEC) of the spatial data object. And open shape model converts the processing of the direction predicates into the processing of topological operations between open shapes and closed geometry objects. So a number of spatial objects were excluded immensely to compute during the filter step, and it is unnecessary to know the boundary of the embedding world and also eliminates the computation related to the world boundary. Our experimental evaluation shows that directional query based on MRD-tree Index and open shape model consistently outperforms classical directional queries based on R-tree and range model while the degree of performance improvement varies by several parameters.