基于面积保持的Douglas-Peucker改进算法的多边形化简

Using Modified Douglas-Peucher Algorithm Based on Area Preservation to Simplify Polygons

面状数据的化简是空间数据多尺度表达和制图综合必须处理的关键问题,有些面状的地理要素要求简化前后面积保持一致,并且不破坏原来的拓扑关系。因此必须对原有的线化简算法做适当的改进。提出对要化简的多边形根据其与相邻多边形的邻接关系,对邻接线段分别化简,以保持原来的拓扑关系;并在采用Douglas-Peucker算法化简时,加入面积平衡的约束条件,构造"平衡线",使化简前后保持面积一致。通过对实验数据化简结果的分析,改进的算法能很好保持化简前后面积及拓扑的一致性,但较Douglas-Peucker算法化简结果,其化简率较小一些。

Polygon simplification is the key issue of cartography generalization and multi-scale representation of spatial data, polygon simplification of some features requires preserving the area and topology relationship, so the line simplification algorithms must be modified to simplify polygon. According to the adjacency relation of the polygons, this paper simplifies the segments of polygon step by step and preserves original topology relationship; when using Douglas-Peucker algorithm to simplify the segment, construct the balance line with area balance constraints. Experimental result showed that this method can not only kept the topology relationship of the polygons, but also maintained the equal of area before and after simplification, but the data compression ratio was lower the Douglas- Peucker algorithm .