| Land desertification is No. one of ten environmental issues in the world. Analyzing dynamic changes of land desertification and the establishment of land desertification combatting management information system may provide significant basis for land desertification control. This research takes the region along the Great Wall in northern Shaanxi as a study area and Landsat TM image at different periods was used to monitor land desertification types and degrees. Forest Resources Inventory data and other related information was combined to analyse land desertification status and its dynamic changes. Based on the data of land desertification dynamic changes and related data of natural conditions and socio-economic development, land desertification combatting management information system was established. The main results were as follows:1) Zhiluo state forest farm located in Yan'an City was taken as the research area, and Landsat TM/ETM image was used as data source. Land-use type map was obtained by supervised classification and compared to Forest Resources Inventory data to verify its accuracy.2) TM images of the year 2004 and 2008 were taken as data sources. Using the same method, the land type map and vegetation cover coefficients of our research area were obtained. Through analysing the type and extent of desertification classification index, we studied the dynamic changes of land desertification. The results showed that the main types of land desertification were wind erosion and water erosion in 2008, and the principal soil erosion degrees were light erosion and moderate, respectively. Compared with 2004, the area of severe and extremely severe desertification region was decreased, while the area of mild-desertification and undesertification region was increased. It indicated that the implementation of ecological projects in recent years has achieved some success.3) Database of desertification information in Shaanxi Province was established. Land desertification data and the related data of the natural environment, and socio-economic statistical data were collected, classified and sorted. The data was entered or imported into the Oracle database.4) Desertification combatting management information system of Shaanxi Province was developed. According to the requirement analysis, prototyping development methodology and C/S structure were used in our study. Taking Visual Basic as the develop environment and MapX as geographic information system tools, the system could be access by different users. And necessary functions, such as data browsing, query, statistics and thematic map production, were developed. |
