Abstract: The flat cross-section map of transmission lines is a crucial basis for optimizing transmission line routes, reducing environmental impact, and lowering costs. Traditional methods for mapping flat cross-sections involve considerable labor and high risk, with low accuracy in estimating vegetation height and rare direct vegetation envelope lines to affect line design. To address this, a method for automatically extracting and drawing flat cross-sections and vegetation envelope lines of transmission lines based on airborne laser point clouds is proposed. The overall technical approach are described firstly. Then, key technologies are investigated in depth, including laser point cloud calculation and DSM construction, filtering and DEM construction, automatic extraction of flat cross-sections with adaptive intervals, and vegetation envelope line simplification algorithms. Finally, through practical cases, the DSM and DEM construction from laser point clouds, extraction of flat cross-sections and vegetation envelope lines, and their accuracy and efficiency are analyzed. Results show that laser point clouds provide high measurement accuracy, enabling fast, accurate, and automated extraction of flat cross-sections and automatic drawing of vegetation envelope lines, So offer significant technical support for optimizing transmission line routes and being worthy of widespread promotion and application.

Key words: UAV, LiDAR, transmission line flat section, vegetation envelope, point cloud filtering, DSM