顾及非线性地形因子的地表面积计算

研究地表面积统计数学模型及其影响因素,消除不同分辨率DEM计算所得地表面积的差异,对综合利用多尺度DEM数据精确统计和监测地表面积具有重要意义。本文研究提出了一种顾及复杂地形因子的地表面积统计方法。该方法首先利用泰勒级数逼近原理对微观地形因子进行最小二乘估计,然后利用这些地形因子对DEM和多边形区域边界进行加密,最后利用加密后的DEM和多边形边界构建地表三角网统计地表面积。试验表明,在局部地形因子显著的山区或丘陵地区,使用不同分辨率DEM所统计的地表面积存在较大的差异,而顾及地形因子的地表面积统计方法可明显提高低分辨率DEM地表面积统计精度。

Surface Area Computation with Regard to Nonlinear Terrain Factors

Mitigating the differences of the surface areas computed by DEM data with different resolutions is meaningful in precisely doing area statistics and monitoring area changes .In this paper ,we discuss the mathematical models to the surface area computation and give the influences to the computational accuracy .An area computation method of polygons on the l andscape surface is proposed and this method has taken local terrain factors into account .Firstly ,the least squares estimation of these local terrain factors is achieved by employing the Taylor series expansion of the spatial function ,then these estimated terrainfactorsareappliedtotheDEMinterpolation.Finally,theregulartriangulatednetworkisstructured to approximate the theoretical area of the landscape surface .Experiments show that ,in the mountainous area or hilly region where the nonlinear topographic signal is prominent ,the computational area heavily relies on the space resolution of the DEM data and the impact to the surface area computation is very serious .However ,due to the using of terrain factors estimated ,the area computation strategy proposed can significantly improve the precision of the computed area from the low resolution DEM .