The assessment model of rocky desertification was built using remote sensing technique

geographic information system technique and principal component analysis method

which was used to assess the present situation of rocky desertification in typical karst mountain area of North Guangdong Province based on TM images of 2004.The results showed that rocky desertification was still severe in study area

the area of most severe

severe and moderate grades of rocky desertification took up 74.03% of the total rocky desertification land

and these rocky desertificated lands mainly distributed in the middle part of Yangshan County and the north west part of Ruyuan County.The assessment results showed little difference with the data of field survey

which indicated that it was a feasible method to assess rocky desertification with the information of rocky desertification landscape extracting from RS images using principal component analysis method with ArcGIS software.