| Chongqing is located in the southeast edge of Sichuan Basin, which is srounded by a few lines of mountains and plateaus forming an enclosed landscape environment. Chongqing is located at the confluence of two rivers (Yangtze River and Jialing River), with high mountains and steep slopes, exposed rock. So it is easy to break out landslides, ranking one of the worst landslide National 70 cities. After the establishment of municipality in 1997, there are several changes, such as the urban construction accelerated, many high-rise buildings emerged, transportation construction mileage increased, and a quantity of artificial side-slope near the city buildings and traffical mountains came into being. Under the double impact of natural conditions and human engineering activities, these situations will be a great inducing factor to landslide, because these slopes may result to deformation, consequently producing instability, and landslides happened. Luckily, the governments at all levels in Chongqing paid more and more attention to Landslide prevention in recent years, and launched a series of "geologic hazard risk zoning" and other prevention programs. How to efficiently use GIS and remote sensing technology to complete high quality and efficient landslide risk zoning and maximizely put these technologies into practice are the main points of this article.This paper, choosing Chongqing Landslide annual plan as the support data, explored the theory and practice of landslide from the perspective of geographic information system and remote sensing methods.The results are as follows:(1)Based on the analysis of research methods at home and abroad, selecting SPOT-5 panchromatic 2.5m and 10m multi-spectral images and Quickbird, aerial photos, DEM and some existed landslide data as basical data, on the platform of RS and GIS the author interpreted 5925 plots of landslide in Chongqing by successful using visul and man machine cooperation method to creat landslide explanation and interpretation symbology. After interpretation,63 superlarge and 3 large landslide points were randomly selected by repeatly field surveys and expert intervention to validate the results, which showed that interpretation of the results consistent with the actual situation in Chongqing. According to the interpreting results, Chongqing Landslide Management Information System had been designed by using File Geodatabase and ArcGIS Engine9.2 spatial database platform, which achieved three module functions:a landslide spatial database management, risk assessment and mapping management, a good foundation for the next landslide risk zoning.(2)By synthesis of landslide interpretation, landslide spatial database and management of geographic information system outcomes, landslide risk and vulnerability assessment factors had been scientificly selected. The author completed risk assessment and vulnerability assessment by the method of principle analysis of statistical analysis algorithms, GIS buffer analysis, overlay analysis, statistical analysis, three-dimensional factor analysis of the landslide to quantify the landslide data. According to vulnerability rank and risk classification, kriging interpolation, re-classification, digital conversion, expert interference correction in following to zoning risk and vulnerability districts. Defining 0.5 as the landslide risk and vulnerability weights, by linear overlaying, landslide risk assessment is divided into three landslide risk areas:high risk area, medium risk area and low risk area.(3)Making full use of geographic information systems and remote sensing principles, the author applied layer stacking and transparent set of three-dimensional visual effect to map six series of landslide risk maps, which provides direct instruction for the landslide year plan.The innovations of this article:(1)GIS spatial analysis had been completely introduced to comprehensive assessment of landslide risk zoning theories. AHP algorithm in GIS successfully quantified and evaluated the risk factors. The application of this technology is important for future landslide research methods, providing successful theory and practical experience for future similar studies.(2)On the basis of existed research, applying a more systematic study method of survey-interpretation-risk assessment-risk division-mapping technology, and combination of spatial analysis of geographic information systems, the landslide risk assessment program had been improved. Organizing the relative landslide risk zoning databases and applying the secondary development of management geographical information system is a successful combination of GIS development and application, and reflects the Landslide GIS trends as well.
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