| 摘要 |
PURPOSE: To obtain a method and device for three-dimensional geographical data generation which makes parts corresponding to not only ridges, but also valleys smooth and distinctively represents them. CONSTITUTION: A ridge and valley information extracting circuit 1 extracts information corresponding to the ridges or valleys from altitude data of the respective vertexes of aimed meshes. A mesh division direction determining circuit 2 performs a process for determining a division direction by using the extraction result. A drawing circuit 3 performs a process for drawing the meshes whose division direction is determined with two triangular polygons. A drawing process circuit 31 divides each mesh into two triangular polygons according to the division direction determined by the division direction determining process for the meshes and draws all the meshes. At a request for redrawing, a redrawing process circuit 32 repeats the drawing process. |
