Abstract: According to the actual demand for the mapping of geographical conditions census, this paper proposes a simplified method considering the original topological relations of the patches. By constructing the topography of the patches, the simplification of the patches is transformed into the simplification of the shared arc which is classified. The corresponding simplified methods are used for different types of arcs. The results show that the method can maintain the structure of the patches and keep the map clean and tidy. The method conforms to the requirements of map mapping, which obtains the good application effect.

Key words: patches, topological relations, simplification, segment classification, geographical conditions census