地理信息系统文献翻译——摘要：地形图最重要的元素之中，地形骨架线是连接峡谷最深点的山谷线，也是连接脊线最高点的山脊线。为了从地形图上获得有关土地形式正确和足够的信息，骨架线必须和等高线一起被考虑和描绘。他们的提取物在不同区域都很重要。他们可以自动地将等高线，数字高程模型或数字图像聚合在一起，不需要土地测量或者摄影模式，在这项研究中，使用了一项从数字高程模型提取山脊线和山谷线的，名为“RidgeValleyAxisPicker”的项目。它是以昌等人（1998）开发的是被资料和多边形间隙（PPA）算法为基础的。“RidgeValleyAxisPicker”和PPA有两个方面的不同：（1）配置不用于对目标识别的步骤，因此，所有的高点作为目标考虑。（2）分支还原过程反复地进行。在10米格网的距离之间，所有在案例研究中使用的数字高程模型的点自动地从比例尺为1:5000地图的模式中收集起来。研究的最后，我从几个方面在同等比例尺的原始地形图的结果中进行比较。在结论中，虽然本文中所描述的关于从DEM中自动提取地形骨架线的方法，可以相当迅速地操作大量的数据，但也有一些关于对提取线制图的问题。

1.引言：

地形图最重要的元素之中，地形骨架线是连接峡谷最深点的山谷线，也是连接脊线最高点的山脊线。地形的骨架线，即山脊线和山谷线是地形图中非常重要的，不可分割的部分。为了从地形图上获得有关土地形式正确和足够的信息，骨架线必须和等高线一起被考虑和描绘。通过在一个只能用等高线代表的地形图中添加地形骨架线的方法，使一些土地的形式结构（如山体，长矛，山脊，山谷等）变得更加可读。

他们可以自动地将等高线，数字高程模型或数字图像聚合在一起，不需要土地测量或者摄影模式。当用任何已知的方法（大地测量，摄影测量调查，自动提取制图）来产生骨架线时都必须注意，骨架线必须反映地形特征，而且等高线的弯曲必须精确（柔伊，1984年）。

地形骨架线的提取物在不同领域具有极大的重要性，如水文应用，军事应用，推广研究，政治边界的确定，最陡坡远足和登山的路径的发现，土地类型的土壤或岩石地形高低程度的描述和决策。排水网络，即山谷线，也可以在地理信息系统中，为土地系统分析和水文资源管理（马克，1984年）形成一个重要元素。因此，许多科学家研究了从高程数据中提取排水网络，以确定水资源和解决水文问题......

ABSTRACT:

Terrain skeleton lines, among the most significant elements of topographical maps, are the valley lines that connect the deepest points of valleys, and the ridge lines that connect the highest points of ridges. In order to obtain correct and enough information about land forms from a topographical map, skeleton lines have to be considered and portrayed together with contours. Their extraction has a great importance in the different areas. They can be gathered from contours, digital elevation models (DEMs) or digital images automatically besides land surveying or photogrammetric stereomodels. In this study, a program called ‘RidgeValleyAxisPicker’ written for extracting ridge and valley lines from DEMs is used. It is based on the algorithm of Profile Recognition and Polygon Breaking (PPA) developed by Chang, et al. (1998). ‘RidgeValleyAxisPicker’ differs with PPA from two aspects: (1) profiles are not used in target recognition step and thus all height points are considered as targets, (2) branch reduction process is performed iteratively. All of the DEM points in 10 meter grid distance that are used in the case study are automatically collected from a stereomodel for a map at the scale 1: 5000. At the end of the study, the results are compared with the original topographic maps at the same scale from several aspects. In conclusion, although the method described in this paper for automatic extraction of terrain skeleton lines from DEMs can be working with huge amount of data quite rapidly, there are some cartographic problems on the extracted lines.

1.INTRODUCTION

Terrain skeleton lines, among the most significant elements of topographical maps, are the valley lines that connect the deepest points of valleys, and the ridge lines that connect the highest points of ridges. Terrain skeleton lines, i.e. valley and ridge lines are very important and inseparable part of topographical maps. In order to obtain correct and enough information about land forms from a topographical map, skeleton lines have to be considered and portrayed together with contours. Some of the land form structures (e.g. hills, pikes, ridges, valleys etc.) become more readable by adding terrain skeleton lines in a topographical map which can only be represented with contours.

Besides skeleton lines are obtained from land surveying or photogrammetric methods, they can be extracted from elevation data automatically. While producing skeleton lines for a topographical map in any of the known ways (geodetic surveys, photogrammetric surveys and automatic extraction cartographically) care must always be taken, that skeleton lines must reflect the characteristics of terrain and the contour lines bend precisely on them (Yoeli, 1984).

Extraction of terrain skeleton lines has a great importance in the different areas where topographical maps are used such......