A Unified Approach for Indexed and Non-Indexed Spatial Joins
Most spatial join algorithms either assume the existence of a spatial index structure that is traversed during the join process, or solve the problem by sorting, partitioning, or on-the-fly index construction. In this paper, the authors develop a simple plane-sweeping algorithm that unifies the index-based and non-index based approaches. This algorithm processes indexed as well as non-indexed inputs, extends naturally to multi-way joins, and can be built easily from a few standard operations. They present the results of a comparative study of the new algorithm with several index-based and non-index based spatial join algorithms.