形态特征约束的地形鞍部点提取方法

Terrain Saddle Point Extraction Method Constrained by Morphological Features

鞍部点是重要的地形特征点,是构建地形结构点簇不可或缺的部分,准确提取鞍部点是开展山地地形空间结构与特征分析的基本内容和基础支撑。本文从鞍部点的形态特征出发,依据其独特的等高线空间拓扑关系,构建了致密等高线缩小逼近鞍部范围,进而确定鞍部点位置的新型的地形鞍部点提取模型。该模型融入形态特征约束机制,探测和提取地形鞍部点,实验结果表明:该模型快速简便,能有效过滤大量伪鞍部点,提取的鞍部点位置精确度和数量准确度高,所获取的鞍部点符合地貌学认知,是一种高效高质量的鞍部点提取方法。

The saddle point is one of the important terrain feature points that reflect the undulation and change of the earth’s surface.The accurate extraction of the saddle point is the basic content and basic support for the analysis of the spatial relationship and structural characteristics of the terrain.The existing DEM-based saddle point extraction algorithm does not realize the accurate judgment of the spatial relationship between the saddle point and the surrounding ridge lines,valley lines,and mountain vertices,resulting in different degrees of deficiencies in the extraction results.This paper analyses the morphological characteristics of saddle points,and based on its unique spatial topological relationship of contour lines,a new terrain saddle point extraction model is constructed to narrow the range of the saddle to determine the position of the saddle point.The model incorporates a morphological feature constraint mechanism to detect and extract terrain saddle points.Comparing with common DEM data extraction methods based on regular grids,this method fully takes into account the geomorphological cognition law of saddle points to get rid of limit by the size of the analysis window.The fast and simple model can effectively filter a large number of false saddle points and achieve saddle points with high position accuracy and quantity accuracy,which are in line with geomorphological cognition.This method is an efficient and high-quality saddle point extraction method.At the same time,it also provides a new research idea for the extraction of terrain feature points that are more integrated into the constraints of geoscience knowledge.