甘肃省沙地的全数字方式遥感宏观研究

Macro scale Study on Sandy Land of Gansu Province Using Remote Sensing in Digital Way

以ＴＭ 影象为信息源，在全数字方式下运用遥感技术与地理信息系统技术结合建立了甘肃省沙地的ＴＭ 图象数据库、图形数据库和属性数据库。用该方法建立空间数据库不仅速度快、精度高，而且数据库具有完整性和一致性高，不同期数据可比性强等特点，可广泛应用于其它空间分布问题的分析研究工作中。通过对已建立的沙地数据库的分析得出甘肃省沙地广泛分布，土地沙漠化现象严重，全省有沙地面积２ ７５０ ８６３ ｈｍ ２ ，占全省总面积的６ ．０５４ ％ 。在８６ 个县区级行政区域单元中３２ 个县市有沙地分布。

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 hm 2 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.