Index structure for managing multi-levels of road networks on distributed environment

With a view to attaining the shareability and consistency of map information under a distributed environment, we propose a multi-level/multi-theme map information model to maintain maps in consistency with original source datasets. However, the distributed management of spatial datasets results in a complex maintenance processing, especially when the modification refers to several datasets. To solve this problem effectually, in this paper we propose an index structure, the MOR-tree (multi-levels-object-relation tree), for organizing the integrated maintenance procedure. The MOR-tree is an extension of the R-tree index structure with the ability of indexing spatial objects of multi-levels in one hierarchy and recording relations among objects at different levels. The performance of MOR-tree is also evaluated with a prototype system in this paper.