建立数字高程模型的多边形区域法

Polygon region method of digital elevation model generation

针对利用等高线地形图建立数字高程模型(DEM)时传统方法需先提取离散点数据、构建大量不规则三角形网(TIN)的繁琐过程,提出简便的多边形区域法.对等高线进行完整性处理并按多边形编号存储,利用既有的等高线及其单边邻接关系将整个地形图划分为相互独立的多边形区域,形成DEM模型;通过搜索查询点所在的多边形区域及对应的等高线高程值,采用距离加权平均法计算查询点的高程.该方法建立的DEM模型明显减少了网格数量和存储空间,高程插值计算精度不低于TIN法.利用多边形区域替代传统的TIN,建模效率提高,适合于建立大型的DEM.

In order to avoid the tedious work in the traditional method generating Digital Elevation Model （DEM） based on the contour map, which picks out vast discrete points and then establishes large Triangulated Irregular Networks （TIN）, the polygon region method was proposed. The disconnected contour line was processed perfectly and saved as polygon, and the unilateral adjacent contour line array data was formed. By the array data, the whole contour map was divided into independent polygon regions and the DEM was established. When inquiring about the altitude of any point in the DEM, the polygon region the point located in should be＇found and the altitude was figured out by distance-weighted average method according to the corresponding elevation value of contour line. The method reduces the number of mesh and the data storage space of the DEM significantly with the same precision as the TIN in altitude inquiring. While replacing the traditional TIN with the polygon region, the polygon method is suitable for large scale DEM generation with higher efficiency.