资源环境科技发展态势分析平台

A river channel network is an important geomorphological feature in a catchment. A method to extract river channels in urban environments from a high-resolution digital elevation model (DEM) is introduced in this paper. The method utilizes terrain transition lines to delineate channel networks. First, terrain transition lines are extracted from the DEM. Then, shallow road ditches are removed based on elevation from the terrain transition lines, and then, noise is removed using the region growing method. Subsequently, most of the road ditches are removed by pixel block expansion, and then, the nonchannel pixels are removed by fitting a quadratic surface. The computational efficiency and accurate localization of river channel extraction using the proposed method is demonstrated using light detection and ranging (LiDAR) data for an urban environment in Johnson County, Iowa. The proposed method is effective for extracting channels and removing road ditches in this urban environment. A potential application of this method is to provide the river channels required for riverine flood modeling and geomorphological studies.