干旱区生态环境知识资源中心

For the fragile-ecosystem arid land, the macro and integral information about the land cover types and area is important for the restoration and the improvement of the ecological environment. In this paper, the arid Gaotai County of Gansu Province, China, was taken as a study case to discuss classified method of the arid land based on various indexes. Taking the advantages of different temporal images into account, two TM images acquired in October and June respectively were selected to conduct the research. Firstly, a series of indexes such as NDVI, vegetation coverage, MNDWI, Albedo, Wetness and SI were calculated. Secondly, combining Robert algorithms and artificial experience methods, the integrated index threshold for distinguishing vegetation from other land types was calculated. Thirdly, using the threshold and decision tree classifier, the middle-high and low coverage vegetation were extracted from both two images. Fourthly, the vegetation areas from two images were combined to form the total vegetation cover types (Oasis), which was used to mask October images, and the outside of mask area was continually classified into the types such as the salinization land, water, bare land and wetlands and other land cover types with decision tree classifier. At last, combining all cover types together, the land cover classification map of whole county was produced. Compared with the land cover types interpreted from the high resolution images and field investigation points, this method was found achieving the accuracy of 91.5%. (C) 2011 Published by Elsevier Ltd. Selection and/or peer-review under responsibility of Conference ESIAT2011 Organization Committee.