A Window Retrieval Algorithm for Spatial Databases Using Quadtrees

An algorithm is presented to answer window queries in a quadtree-based spatial database environment by retrieving the covering blocks in the underlying spatial database. It works by decomposing the window operation into suboperations over smaller window partitions. These partitions are the quadtree blocks corresponding to the window. Although a block b in the underlying spatial database may cover several of the smaller window partitions, b is only retrieved once. As a result, the algorithm generates an optimal number of disk I/O requests to answer a window query (i.e., one request per covering block). The algorithm uses an auxiliary main-memory data structure, called the active border, which requires additional storage of O(n), for a window query of size n n. An analysis of the algorithm's execution time and space requirements are given, as are some experimental results.

• Type: Conference
• Year: 1995
• Where: GIS
• Authors: Walid G. Aref, Hanan Samet
• Keywords: Automated Reasoning, GIS 1995, Smaller Window Partitions, Spatial Database, Window