Using digital processing method of remote sensing and GIS

TM images in 1996 are interpreted and the database of the sandy land in Gansu province is established. It includes TM image

graph (scale 1∶100 000) and its attributing database. In order to interpret correctly

the interpreting insignia system of sandy land on TM images has been established through analyzing the relative reference and images and then been corrected in the fields. The definition of the sandy land is covered by sand

the vegetation is lower than 5%

and it includes sand desert. Through the study practice and analyzing of sandy land databases

the following conclusions can be gained: (1) In Gansu province

there is as much as 2 750 863 hm2 sandy land occupying 6.054% of the area. And of the 86 county units of the province

there is 32 counties distributed by sandy land. (2) Comparing with traditional methods

there are many advantages using digital processing method to establish the sandy land database such as

mapping rapidly

high accuracy and lower expenses. (3) With the same interpreting insignia and graphical database and attributing database that are well matched with image database

the sandy land can be monitored accurately in large scales.