Study on the dynamic change of soil erosion in Hunan Province by "3S" technology

Dynamic change of soil erosion in Hunan province was investigated by the utilization of '3S' technology.The results showed that: ① The status of soil erosion in 1995 and 2000 indicated that in the spatial distribution it decreased in a saddle pattern from the eastern and western side to central section in the east-west direction and long wave in the south-north direction;② The main soil erosion of Hunan Province in 1995 were hydraulic erosion,gravitation erosion and engineering erosion,the hydraulic erosion was the main erosion of them and apart 98.85% of total erosion in 1995.And only the hydraulic erosion exist in 2000;③ The area of soil erosion declined as the time went.Compared with 1995,the area of soil erosion decreased by 728.55km2 in 2000.Apparently,some intensity grades of soil erosion aggravated and others weakened.The increased area of some intensity grades of soil erosion was a feint that resulted from the transformation by the treatment of soil erosion regions of a graver intensity grade or more;④ By the precision test,the average estimation precision was 89.83 percent.