Mapping the land slope and the land slope grade of the Sichuan Province based on the DEM

The first land survey of China has been implemented based on the traditional survey methods, and the inaccuracy of area for different land use type is not suitable for the need of land use management until now. In order to supply the spatial pattern and accurate area of the difference land use type, the government carried out the Second land investigation on 2009, and the land slope mapping and the land slope grade map is the basic and key work for the Second land investigation. The present paper develops a calculating model of land slope and computer software to analyze the topography and geomorphology of the Sichuan Province using the topography data. The land slope map and land slope grade map is constructed according to DEM data, and the result have been validated by experiment zone. The result of the land slope map and land grade map for the Sichuan Province shows that the result is credible to the Second National Land Investigation.