On past-time indexing of moving objects

Tracking of mobile objects trajectories is one of many modern applications supported by Spatiotemporal databases. Within the context of this application, queries about the present, future or past positions of the objects need to be answered. Several indexing methods have been proposed to efficiently handle such spatiotemporal queries. In the current paper, we propose a method for indexing the historic (past) positions of moving objects called XBR-tree, a quadtree-like technique that is able to handle both timestamp and window queries. Moreover, we compare experimentally this with other methods proposed in the literature for the same purpose. In particular, we compare XBR-trees with PMR-trees, structures also related to quadtrees and MV3R-trees, R-tree based structures.