Geometry Characteristic and the Tracing of Flown Lines Combined to Extract Terrain Structure Lines

A new method for automatic extraction of structure lines is developed by the new(idea) includes 3D physical analysis and 2D geometrical analysis.The new idea is based on the fact that the flown line whose start point is a valley point at upriver always flows along the lowest direction,and the flown line is also a valley line.A real contour map was used as testing data.As the result,the valley lines extracted automatically by this method can basically represent the topographic features of the corresponding topographical map.The new method takes advantages of 2D geometrical analysis and 3D terrain analysis and it is effective.