It is discovered that the correlation between msavi ( modified soil adjusted vegetation index ) and vegetation coverage is higher than that between ndvi ( normalized differential vegetation index ) and grassland coverage when the land cover is low . so msavi can be used as the main index of grassland desertification degree . in order to evaluate the precision of the result, different methods such as supervised classification, unsupervised classification and visual interpretation on image are tried respectively 本文將其作為草地沙化的分級(jí)指標(biāo),直接通過(guò)計(jì)算分級(jí),建立msavi等級(jí)與草地沙化程度的對(duì)應(yīng)關(guān)系,確定草地沙化的程度,然后將msavl分類(lèi)結(jié)果分別與目視解譯、監(jiān)督、非監(jiān)督分類(lèi)的結(jié)果進(jìn)行了精度比較,其精度高于監(jiān)督與非監(jiān)督分類(lèi),與典型區(qū)現(xiàn)場(chǎng)繪制和目視解譯結(jié)果的誤差為5.9,能滿(mǎn)足草地沙化監(jiān)測(cè)實(shí)際應(yīng)用要求。