The xBR+-tree: an efficient access method for points

Abstract. Spatial indexes, such as those based on Quadtree, are impor-tant in spatial databases for efficient execution of queries involving spatial constraints. In this paper, we present improvements of the xBR-tree (a member of the Quadtree family) with modified internal node structure and tree building process, called xBR+-tree. We highlight the differ-ences of the algorithms for processing single dataset queries between the xBR and xBR+-trees and we demonstrate performance results (I/O effi-ciency and execution time) of extensive experimentation (based on real and synthetic datasets) on tree building process and processing of single dataset queries, using the two structures. These results show that the two trees are comparable, regarding their building performance, however, the xBR+-tree is an overall winner, regarding spatial query processing