RS-GIS-Based Current Situation And Prevention Of Partition Research Into The Rocky-desertification

Rocky-desertification is a process of land degenerating results from the vegetation destruction, soil erosion and bedrock exposed which occurs in karst area as a result of the natural evolution and the unreasonable human activities under the frail ecological conditions. In western China, following the desertification and soil erosion, rocky-desertification has become the third largest ecological problem which deteriorates the regional ecological environment, declines the land productivity, and causes the shortage of water resources and regional poverty. The significance of rocky-desertification governance is to guarantee the ecology security, narrow the gap among regions and promote social harmony. Only with the fully awareness of status of rocky-desertification, forming reasons, scientific prevention works of different rocky-desertification regions,corresponding choices of adjustment measures and models to local conditions, can we effectively prevent and control desertification.In this paper, we take Fengjie in Chongqing as an instance to study remote sensing interpretation by the methods of GIS automatic extraction of desertification information and man-computer interactive interpretation modify rocky-desertification which supports by the remote sensing and geographic information system.The computer automatic extraction of desertification information is based on the secondary image analysis system of MAPGIS, which based on the TM images of different grade rocky-desertification in the terrain on the brightness range differences establish classified rules. And using the percentage statistical classifier developed by land resources remote sensing center aerogeophysical of China, we can quickly extract desertification information. Comparing with traditional visual interpretation, the precision of this method is higher. When doing researches in small area information extraction of remote sensing image computer cartography, we found that the key link of the accuracy in drawing information is the second analysis. When we correct the results of link information analysis classification we got in the first time point by point, it can be found that the more sample points we correct, the higher precision the results is. This paper is divided into six parts, the main contents and conclusions are:1. To carry on the preparatory work of rocky desertification remote sensing, including selection of remote sensing image based data, collection and pretreatment, and carbonate distribution drawing.2. Using the secondary image analysis system which is developed by aerogeophysical center for remote sensing of land and resources of China and based on MAPGIS platform, we can realize the automatic interpretation of rocky desertification information. With the auxiliary modification in the form of man-computer interactive interpretation, the interpretation accuracy and precision can be improved. This part is the focus of this article.3. By the wild work, we can examine the results of remote sensing to rocky-desertification.4. The operation platform is Arc Map9.0and the ARC/INFO9.0which carries on the statistical analysis to the results of remote sensing data. The conclusion is that the rocky-desertification land of Fengjie is1108.91km2, accounting for27.05%of the whole land area; Potential rocky-desertification land is560.99km2, accounting for13.69%of the land area. In the rocky-desertification land, mild rocky-desertification is342.21km2; moderate rocky-desertification is628.17km2; severe rocky-desertification and the extremely severe rocky-desertification are138.53km2, which the proportion of them to the whole rocky-desertification area is30.86%,56.65%and12.49%, respectively.5. Through the investigation of distribution of rocky desertification, combining with the results of remote sensing interpretation, we can analysis the formation mechanisms of rocky desertification. The conclusion shows that human factors are main reasons to the rocky-desertification, accounting for98.97%. On the other hand, natural factors account1.03%only. In human factors, the rates of all factors to rocky-desertification can be ordered from the highest to the lowest which is excessive logging, inappropriate management methods, industrial pollution and overgrazing.6. On the basis of present study on rocky-desertification and rocky-desertification formation mechanism, it can be divided into different rocky-desertification prevention and control regions scientifically. Aiming at the different natural environmental conditions, social economic conditions and rocky-desertification status of each region, we can choose different governance approaches and modes against the local conditions. Such as infrastructure construction, water conservation project in the construction of basic farmland, returning farmland to forest (grass),terrance, planting of special economic fruit tree and normal trees.All of them are effective measures for karst rocky-desertification governance.