Wanzhou District Of Gis Landslide Hazard Evaluation Studies

With constant improvement of the theories of GIS and rapid development of technology, the technology of GIS has been widely applied to all the current fields related to spatial information beyond the initial limited field. In particular, since 1990s the further improvement of GIS theories has made various commercial software of GIS with powerful functions and a lot of practical software of GIS appear, which advances the GIS to develop in all applied fields. Moreover, with the forthcoming sluicing of the reservoir of Three Gorges, such geological hazards in the reservoir area as landslide and rockfall are becoming more and more. Even Chinese government has transferred special funds of four billion yuan for solving this problem. In this background, it is emergent to apply the latest technology of GIS to the researches on the geographical hazards. This paper focuses on the core problem of the research of geographical hazards, hazard assessment, takes geological hazards of landslide in Wanzhou as an example and attempts to use the technology of GIS in hazard assessment of landslide so as to solve such problems in past geographical hazard assessment as low efficiency, bad accuracy, and waste of time and strength and to make hazard assessment of landslide informed and scientific. In the process of researching, this paper constructs a workflow based on ArcGIS to have the hazard assessment of landslide with Logistic Regression analysis and Information Value Method. On the basis of mapping unit of 50m×50m the paper makes use of Logistic Regression analysis and Information Value Method respectively to have a hazard assessment of landslide on main urban areas of Wanzhou and gets a hazard map finally. The research in this paper makes the following achievements:(1) A set of complete technological assessment route and work process based on GIS hazard assessment is set up specially for the mountain area of Wanzhou. This system includes problem analysis â†' establishment of standards â†' preparation of assessment factors in GIS environment â†' building database of hazard assessment â†' model analysis of hazard assessment â†' confirmation of results of hazard assessment and GIS presentation.(2) The fundamental methods of coordinating GIS and professional statistic software to input and output data to have a hazard assessment of landslide are concluded.(3) The function of spatial analysis of GIS is made full use of. The fundamental methods and work process with the analysis function of spatial overlap of raster data to have a hazard assessment of landslide are foundout.(4) The logistic regression analysis mode and Information Value Method are successfully used to have a hazard assessment of landslide and have had an ideal effect.(5) The hazard map is got by two kinds of methods of hazard assessment. Afterthe analysis two kinds of assessment results both show that the most dangerous area in main urban area of Wanzhou distributes the area along both sides of ZhuXiHe and the left side of Yangtze River. This result agrees with the actual distribution of landslide, which proves that the assessment result is effective.It is proved by practice that in comparison with the hazard assessment of landslide based on paper map, the GIS-based hazard assessment of landslide is faster and more effective. Coordinating with appropriate assessment model it can replace the traditional method of hazard assessment so as to improve the efficiency and the accuracy of hazard assessment of geographical hazards. The result shows that the combination of Logistic Regression and Information Value model with GIS is effective in assessment of geological hazards risk. Then, the hazard assessment of geographical hazards advances further in modelized, quantified and modernized direction.