等高线树构建及高保真DEM构建

Constructing contour tree and DEM construction of high fidelity

研究正负地貌等高线(含未闭合等高线)的空间关系。首先将未闭合等高线分为完全开放等高线和贴边等高线,分别进行自动闭合处理。然后使用多边形叠加分析的方法判断闭合等高线之间的关系,构建等高线树。通过对等高线树结构的遍历,获取格网点高程值的上下界,将上下界输入到高精度曲面建模区域优化控制方法进行约束优化控制模拟,能保证模拟结果的回放等高线与原始等高线的最大距离不超过一个栅格的宽度。最后对高斯合成曲面和扫描矢量化等高线两个实例进行论证。

How to generate contour tree of positive and negative topography from open contour lines, half-open contour lines and closed contour lines is proposed. Half-open contour lines and open contour lines are separated and handled respectively. Then a polygon overlay function is used to decide the spatial relation between closed contours, resulting in contour trees. Through navigating the tree of contour lines, height bounds for every grid in the research region can be deduced, which is then used with HASMROC（region optimum control） method to construct DEM of fidelity. The maximum deviation distance of derived contours is less than the width of the grid of the DEM. Two case studies are given, one is contours from mathematical surface, another is from the manually vectorizing contours lines.