一种基于谷地填充的DEM综合方法

The DEM Generalization Based on the Filling Valley Coverage

提出一种基于次要谷地特征识别与填充的结构化DEM综合方法,该方法将地理层次的综合决策与几何层次综合操作整合到一起,以水文重要性作为谷地取舍的依据,对被舍弃的次要谷地填充其覆盖区域使局部地形变得平滑,从而实现DEM综合。该方法的原理基于如下考虑:地貌形态是内力和外力作用共同影响的结果,内力地质构造形成主要形态,外力侵蚀作用形成次要形态。旨在获得地貌主体特征简化表达的DEM综合可看做是一个弃除外力作用、还原内力作用的过程。通过实验及与其他基于图像处理算法(如重采样、低通滤波)的比较,发现本方法能够较好地保持地形特征的主体结构。

This study presents a structured approach to generalize DEM data through the identification of minor valley and filling the corresponding grids. The generalization process includes two steps： geographic decision and geometric operation. According to the hydrological significance, the unimportant valley branches are detected and then the corresponding coverage isfilled by raising the terrain to make the terrain surface smoother. The motivation of this method is based on the consideration that topographic form is the integrated result of internal and external forces with the former constructing the main landform and the latter generating the minor tandform. The terrain generalization is to obtain the original and main landform by reducing effects by external force. In contrast to the conventional algorithms based on the image processing, such as resample or low-pass filter, this method is able to remain the main geographical characteristics more effectively in terrain representation.