An algorithm for implementing the differentiation of spatial topological relations between lines based on Oracle Spatial Topology Data Model

To extend the applications of Oracle Spatial Topology Data Model (OSTDM) within spatial relations, the study presents an algorithm for OSTDM to determine the nine elements of the 9-intersection matrix that can be used to differentiate the 33 kinds of spatial topological relations between the two lines described in the 9-intersection model. Three elements about the boundary of line A can be determined by using the two extreme nodes of the line A to differentiate the spatial topological relations with line B. Two elements about the boundary of line B can be determined by using the two extreme nodes of the line B to differentiate the spatial topological relations with line A. Three elements about the interior of line A and line B can be determined by using both edges of the two lines to differentiate the spatial topological relations with each other. The last one element about the exterior of line A and line B can be determined by using the infiniteness of the exterior of spatial lines. The algorithm was designed to avoid the use of Oracle Spatial functions and thus can be run faster, and was proved to be valid by practice in programming.