The Analysis of Land Desertification Changing of Minqin County in Recent 30 Years
近30年来民勤土地荒漠化变化遥感分析

Aided by GPS, geometric correction of aero photos of 70s, TM images of 80s and 90s were accurately done for desertification analysis. And they were also consolidated to the same projection. Based on setting up of accordant interpretation keys and managing and analyzing of desertification land information by GIS, dynamic change of desertification land was investigated in Minqin County of Gansu Province, a typical desertification region. The results show: the area of desertification land in Minqin County tends to enlarging in recent 30a. However, the spreading rate was slow down since 1985. The areas of active dune and semi active dune are increasing continually while the areas of fixed dune and semi fixed dune were controlled effectively. Finally, the reasons of desertification changing of this region were discussed in two aspects including both natural environment and social factors by fieldwork and data analyzing.