干旱区生态环境知识资源中心

The quantitative evaluation of desertification extent with remotely sensed imagery has been a hot spot of remote sensing application research. The evaluation process should consider the principles of dominance, integration and so on. Traditional evaluation methods to desertification extent are usually carried out at the scale of discrete pixels, which fails to taken into account of the influence of adjacent pixels and results in noises on the evaluation result images, inducing the unilateralism result. If we try to use filters to reduce the noises, then the evaluation results will be wrong contrasting with its real result. Based on former researches and the geographic science principle, this paper discusses the method of assessing desertification extent at the scale of geographic unit, in which the geographic unit is determined by vegetation coverage index and spatial information. The test results show that this method provides more accurate assessment of the ground situation avoiding the limitations of traditional methods.