Research On Urban Land Use Change And Ecological Effect Based On ZY-3 Satellite Image

City is the epitome of human activity,and is constantly undergoing rapid change.With the development of urbanization,ecological environment problems are also increasing.Since entering the 21 st century,domestic high-profile satellites launched one after another.Land-use survey using satellite data moved toward domestic satellites.Resource No.3 satellite is China's first self-developed resources high resolution stereo mapping satellite,so far our country has access to a wealth of high score data,but for land use based on three images monitoring technology is not yet mature.In order to rapidly promote the application of domestic satellites in the analysis of land use change and ecological effect analysis,it is necessary to carry out relevant research on image No.3satellite.This paper takes the main urban area of Nanjing as a study area,extracts the information of urban land use change with the data of three different phases of resources,analyzes the ecological effect caused by the analysis,and accumulates the experience and technology for the application of the domestic satellite in the relevant field experience and technical methods,the main research contents are as follows:(1)According to the characteristics of the three images,the orthographic image of the study area image is produced,and the technical process of the pretreatment is summarized.The results of fusion methods such as image mean,average gradient,deviation index and information entropy are evaluated by MATLAB software,and the effects of fusion methods such as Brovey,PCA,HPF and NNDiffuse are evaluated,then summarizes the fusion methods applicable to the three images.(2)Research on the key steps of object-oriented information extraction,includes the separation scale and the establishment of rule set.The maximum area method and mean variance method are used to determine the optimal scale of image segmentation.The rule set of information extraction is established by using classification feature.OSTU algorithmis implemented based on MATLAB software,the threshold of custom feature is determined adaptively,and the process of determining the classification threshold is simplified.(3)According to the results of land use information extraction,the estimated value is revised according to the actual situation of the study area,and the ecosystem service value of Nanjing city is estimated.Based on the land use transfer matrix,the overall ecological and environmental effects caused by land use change in the study area and the types of land transfer that lead to the change of ecological environment quality are analyzed,which provide some data support for the relevant departments to formulate effective ecological and environmental protection policies.To build evaluation index model,aselected from the aspects of land resources,society,environment and other aspects,and the weight of each index is determined based on principal component analysis.And evaluated the ecological vulnerability of the study area,summarized the influencing factors of ecological stability and put forward the corresponding improvement suggestions.