Site Division Based On GIS In Subsidence Area Of Shang Wan

This paper chooses subsidence area of Shang Wan as the study area, and does research on one project in this area as a result of its complete materials, and precise data. According the principle of classification of site type and the association with the fact of Shangwan, the predominant factors of site type have been theoretically choosed.The map of multi-factors of site type has been stacked up supported by GIS. Through the overlaying analysis of domestic factor monographic maps, the result of site classification can be worked out and related monographic map of subsided land in Shangwan by analysis of which we can quickly, visually and precisely recognize the distribution and specialty of the different site types. The result showed that :1. Combined with previous research result and actual situation investigation, aspect, slope and sand's thickness at the pit can be chosen as the main factor in subsidence area in Shangwan, and it can be obtained the mantic map of the different factor by GIS.2. According the comprehensive overlay analysis of the different factor, finally, it can be concluded the mastic map of the different factor in subsidence area in Shangwan. Base on the map, this study area can be divided 21 site type, they are half shady flat slope and middle soil layer of sand's thickness at the pit, shade flat slope and thin soil layer of sand's thickness at the pit, half sunny gentle slope and middle soil layer of sand's thickness at the pit, sunny flat slope and middle soil layer of sand's thickness at the pit, shady gentle slope and middle soil layer of sand's thickness at the pit, shady gentle slope and thin soil layer of sand's thickness at the pit, sunny gentle slope and middle soil layer of sand's thickness at the pit, sunny gentle slope and thin soil layer of sand's thickness at the pit, half sunny gentle slope and thin soil layer of sand's thickness at the pit, half sunny flat slope and thin soil layer of sand's thickness at the pit and so on. Among them, the amount of the half shady flat slope and middle soil layer of sand's thickness at the pit is the most, which accounts for 33.205 percent of the whole area. And the sun slope and thick soil layer of sand's thickness at the pit is the least, which accounts for 0.139 percent of the whole area.3. In combination with the vegetation growth situation, studying the site type of the vegetation construction and the species selection, on the basis of the ecological restoration principle, it can be obtained the suitable forestation mode in the study area. And the planting mode of the specific tree species mainly contain the mixed planting mode of the locust and buckthorn or willow and caragana etc.As well as planting simple arbor such as Simon poplar, willow and scotch pine.