Progressive Graphical Simplification of Contour Lines Based on Topographical Feature Constraints

In order to reduce the points on contour lines, an optimized model based on progressive simplifying method for contour lines satisfied by the terrain feature constraints is proposed. Firstly the topographical characteristic points and feature lines are extracted Based on Constraint Delaunay TIN, and then constraints of the contour lines are analyzed systematically and quantified independently, And then the non-feature points, feature points, feature lines and the bends on the contour lines are deleted step by step according to the importance of constraints quantified, and simplified contour lines are achieved at last.