The Ecological Security Assessment Of Earthquake-stricken Area Based On RS And GIS Technology

The May 12 Wenchuan major earthquake destroyed the whole city of Dujiangyan, brought the people to disaster areas tremensdous physical and mental suffering,resulted in severe damage to infrastructure,urban and rural housing,while the economic and social development has been stagnant for a while.Many quake-afflicted people are in urgent need of production and living housing,through the construction of temporary,permanent dwellings.Due to the potential danger of secondary geological disasters,parts of City and Country have to choose the new site to build.Therefore,it's urgent to began the re-construction of Dujiangyan,which is one of the worst earthquake-stricken areas.The primary commitment of re-construction after earthquake is selecting sites and planning,which not only have to meet the rapidly growing demand for construction land,but also to consider sustainable development of the earthquake-stricken areas and the ability to cope with future earthquake disasters,aiming at the specificity of the damaged area.And ecological security assessment is recognization,judgement and research about the integrity of the ecosystem,as well as the sustainability to maintain its health amid various risks. Ecological security assessment of the earthquake-stricken areas is not only the security measures of a regional security and suitability,but also can provide an important basis for decision making during the reconstruction of earthquake-stricken areas of planning and site selection.With the support of RS and GIS technology ,the thesis make eco - safety assessment of Dujiangyan,provide a foundation for reconstruction after earthquake and afford reference for construction units and government decision-making. The main research results are as follows:(1) According to DPSIR (driving force - pressure - state - impact - response) model,the thesis set up ecological security evaluation index system and evaluation criteria of Dujiangyan after the earthquake .(2) Achieving the integration of geographic data,provide data support for GIS decision analysis.(3) Based on RS and GIS technology,combining the actual situation of Dujiangyan after the earthquake, it has accomplished information extraction of various factor in evaluation index system and their topic maps that provides important reference for the feasibility study of post-earthquake reconstruction project.(4) In the process of ecological security assessment,the study hae combinied GIS and MATLAB software and used composite index model and the histogram image segmentation method to get the result , then validate the result that superimposed with the potential geological disasters measured after the earthquake and topographic features.The consequence showed that the entire ecological security level of Dujiangyan is a bit lower than general standard. When we reconstruct after the earthquake,We should choose higher ecological security regions to layout,in accordance with the principles of easier part first and establish new to drive the old.