Abstract: 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 landscape 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 terrain factors are applied to the DEM interpolation. Finally, the regular triangulated network is structured 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.

Key words: geographic national condition monitoring, landscape surface area, terrain factor, DEM, Taylor series, spatial interpolation