METHOD AND APPARATUS FOR EFFICIENT PROXIMITY SEARCHING

A method and apparatus to improve proximity searching. An area containing a population of points is subdivided into a plurality of regions at index time. The population of points and the regions are textual keyed. Attribute(s) are determined corresponding to at least a subset of points from the population. Each attribute or pair of attributes is assigned a bitmap, the bitmap having entries corresponding to the regions in the area. Each entry of the bitmap corresponding to a region having at least one point to which the attribute applies is set. The attribute is then stored in an index with its bitmap. At query time, scanning the bitmap for set bits identifies all potentially relevant regions. These regions may be searched in increasing distance from a spatial origin without incurring the cost of searching fruitless regions.