Study On The Structured Generalization Method Of Contour Lines

As one of the important thesis in map generalization, generalization of relief forms is always the most complex and important aspect and is researched by many scholars all over the world. Based on comprehensive analysis of the existed research on generalization of relief forms, the idea of manual generalization and construction are adopted in this paper. Based on the above ideas, research and experiment on platform generalization is done. Main content and innovation of the research are:1. The contour lines disconnection processing and its application. A new method based on space cognitive is proposed, and automatic tracking and connecting of disconnected lines are realized, based on which contour tree is constructed.2. Algorithm of finding characteristics vertexes of vector contour lines and algorithm of contour lines simplification. An algorithm of finding characteristics vertexes of contour lines based on the furthest visibility condition is proposed.3. Extraction of terrain structure lines based on vector data of contour lines and the establishment of hierarchical relationship. According to the grade of feature points in one group and relevant characteristics of terrain structure lines, structure lines of terrain is connected and their hierarchical relationship is established.4. Guided by the hierarchical relationship of terrain structure lines, the structured generalization method of contour lines is studied. Structured generalization method based on contour lines and DEM are designed separately and a parabolic two-way fitting method used in deleting valley is proposed.