The Study On Method Of Basins Identification And Foothill Lines Extraction Based On DEM

Digital Elevation Model(DEM)is the most important national fundamental geographic information data.DEM-based identification and feature extraction of geomorphic terrain are important application of digital terrain analysis in various study areas such as geography,geomorphology and geographical information science.Basin is a major landform type which consists of plains,hills and mountains.It is high around and low in the center in a basin-like shape.Basin can obstruct the air flow to a certain degree,and therefore,may have a great impact on regional climate,and there tends to be abundant mineral resources in its edge.According to the landform feature and geometric shape of the basin,the paper proposes the identification method of the basin on the basis of the related terrain factor and landform index.In addition,in order to better distinguish massif from flat ground,a more reasonable approach needs to be designed to extract the foothill line.The paper is mainly prepared in the following two aspects:Presenting a basins identification method based on morphological characteristics and geometrical characteristics of the basin.The proposed method first use K-Means clustering algorithm to divide the geomorphic types with the parameters of altitude and relief amplitude,and then establishes closure model that describes morphology of basin combining geometrical characteristics of the basin,and finally automatically identifies the basin area combining area,relative elevation and other geomorphological indicators.To the problem that only a single terrain factor is considered in extraction of the hillfoot line at present,dividing the massif parts according to the definition and connotation characteristics of hillfoot line and through combination of slope,plan curvature,profile curvature and other microscopic topographical factors,and extracts the hillfoot that splits the massif and flat ground combining the mountain's base height.