摘要
结构线是地貌形态的骨架线,是描述地貌形态时的控制线,它在地图制图综合、遥感数字图像处理和扩充GIS 系统的应用功能上均有重要的意义。文中给出了从等高线数据中确定特征点的算法,并对整个图幅内全部特征点的确定方法进行了改进:以整体分析与局部分析相结合,根据局部地形特征的不同,使用不同的阈值分区确定特征点。然后通过建立数学模型匹配特征点生成结构线。为了提高结构线的应用潜力,在生成结构线的同时提取了结构线的分级信息,并将生成的结构线按树结构组织存储。实验结果表明该方法对任何特征的地形等高线数据均适用, 而且最后生成的结构线具有较好的完整性和较高的精确性。
Terrain structure lines are the skeleton lines of the physiognomy and they mainly include ridge lines and valley lines. Terrain structure lines do not directly exist in the original contour data, but they can be derived from the original contour data. In a sense, they are more important than contours in Geographical Information System （GIS） because terrain structure lines can play an important role in the cartographic generalization, processing of terrain sensing digital image, construction of precise digital elevation model （DEM）, hydrographic analysis, mineral deposition, land erosion and extension, the other functions of GIS etc. With the rapid development of GIS, terrain analysis has attracted more attention of the researchers in this field. And the automatic extraction of terrain structure line is a very important problem in terrain analysis. The automatic extraction of terrain structure line usually includes two steps, namely, confirming feature points and linking the feature points to create the terrain structure lines. The first step is decisive for the eventual result and the method is different when using different algorithms. But the second step is always the same. An algorithm for confirming feature points on contours is presented in this paper and the process to confirm all feature points in the whole studied region is improved：according to the difference of the local landscape feature, the feature points in each local region are confirmed using different thresholds which are only adaptive to the local region instead of confirming all the feature points in the whole region using the same threshold. This improvement is very rational because the variation of the landscape is taken into account. Then, based on the established mathematical model, the terrain structure lines are acquired by matching all the feature points confirmed in the whole studied region. In order to make the extracted terrain structure lines more useful, all the terrain structure lines are organized in the form of tree structure and the grade of each branch is available. Because of the complexity and multiplicity of the terrain, few errors are likely to exist in the automatically extracted terrain structure lines, so few manual editing is sometimes necessary to correct these errors. Many experiments proved that the presented method adapts to all the different landscapes, furthermore, the terrain structure lines extracted by this method are integrated and precise.
出处
《地球信息科学》
CSCD
2005年第3期113-119,共7页
Geo-information Science
基金
国家基础测绘科技计划资助项目(项目编号:1469990324231)。
关键词
结构线
等高线
树结构
分级信息
terrain structure line
contour
tree structure
branch grade
