The twin grid file: A nearly space optimal index structure

Abstract

Index structures for points, supporting spatial searching, usually suffer from an undesirably low storage space utilization. We show how a dynamically changing set of points can be distributed among two grid files in such a way that storage space utilization is close to optimal. Insertions and deletions trigger the redistribution of points among the two grid files. The number of bucket accesses for redistributing points and the storage space utilization vary with the selected amount of redistribution efforts. Typical range queries — the most important spatial search operations — can be answered at least as fast as in the standard grid file.