Topographic feature line automatic extraction algorithm

The invention discloses a topographic feature line automatic extraction algorithm. The algorithm comprises the following steps: constructing a triangulated irregular network TIN according to existing elevation data; extracting a 3R triangle; traversing to generate a node binary tree; generating a terrain control line by using the node binary tree; simplifying a terrain control line; and assigning elevation to the terrain control line. The high-precision digital elevation model obtained by using the existing basic surveying and mapping data and the method for automatically extracting the topographic feature lines can meet the three-level precision index of 1: 2000DEM, is applied to provincial-level live-action three-dimensional high-precision geographic scene production, greatly improves the production efficiency, and has the advantage of greatly reducing the cost compared with other similar algorithms. The method has the characteristics of high efficiency, few thresholds, less manual intervention, passing of