GIS中基于拓扑信息的矢量图形叠置方法

Algorithm on polygon overlaying based on topological information in GIS

针对GIS系统中实现无拓扑信息多边形叠置过程复杂的问题,提出了一种新的快速多边形叠置方法.通过在无拓扑矢量数据中局部引入拓扑关系,对同一结点连接的弧段,采用二叉树方法进行排序,构建最小多边形,完成无拓扑信息的矢量图形的重组,并对新算法与已有算法的结构进行了对比.研究结果表明,这种新的叠置算法实现过程简单,速度快,避免了全局构建拓扑关系数据量大、空间和时间关系复杂、维护和更新困难等问题.

Aiming at the difficulty of polygon overlaying for data with no topological information in the geographical information system （GIS） spatial database, a novel quick algorithm on polygon overlaying based on topological information is presented. Local topological information is imported to the altered polygon in this new algorithm. The arcs which are joined in the same node are ordered by means of bina sorting tree, and the minimal polygons are built by the right sequence of arcs, then polygon overlaying is finished. The new algorithm is compared with the existed algorithm, the resuits show that the process of polygon overlaying is predigested and the efficiency of it is improved by the new algorithm. The problems of mass data and the time-spatial complexity are avoided, and the difficulties of maintenance and updating for topological relationships are left out.