Remote Sensing Monitoring Of Urban Spatial Structure And Urbanization Level Analysis Based On Landsat And DMSP/OLS Data

Since China's reform and opening up in 1978,cities are more abundant in employment opportunities and human resources than in rural areas.The influx of large numbers of people into cities has made our cities develop rapidly in economy,education,medical treatment,science,technology and infrastructure.However,the original scope of the city no longer meet the development needs of the age,so the scope of China's urban is expanding in different forms and ways of development.When industry and urbanization develop to a certain extent,metropolitan areas and metropolitan areas also develop,and gradually form urban agglomerations.DMSP / OLS night light data,as remote sensing data for studying human activities and monitoring early warning,also provide an important data source and reference for studying the process of urban development and change.This paper chooses Dianzhong Urban Agglomeration as the research area,selects Landsat images and DMSP / OLS lighting data from 1992 to 2013 and extracts the impervious surface of the city by using a variety of index combination methods,then determines the urban scope according to the threshold method,and finally obtains the more accurate urban built-up area scope of Dianzhong Urban Agglomeration.Based on the extracted results of the urban impervious surface,the spatial structure changes of the urban agglomerations in central Yunnan during the past 21 years were monitored by means of GIS spatial analysis and mathematical statistics.Finally,the urbanization level of Dianzhong Urban Agglomeration is estimated by using statistical data and light data index.The specific contents and preliminary conclusions are as follows:(1)The SAVI and BSI indexes of Landsat images were calculated,and the thresholds of light intensity of each city were obtained by repeated experiments.The urban impervious surface of central Yunnan urban agglomeration were extracted by decision tree classification method.The experimental results show that if the index method is used only to extract the impervious surface of a city,there will be a large number of misclassification problems.However,adding DMSP / OLS data can more accurately determine the scope of urban impervious surface and reduce the error between the extracted results and the actual area.(2)Based on the extraction results of urban built-up area,using spatial analysis methods and mathematical models,calculation of city group of different administrative divisions under the city scale in Yunnan area of the relevant index,detailed analysis of city spatial structure characteristics,the calculation of the spatial structure change index is divided into quantity change,spatial pattern Changes,the strength of urban spatial connection three parts.From the overall change of the study area,the urban built-up area of the study area increased year by year from 1992 to 2013,and the expansion rate also increased year by year.The center of gravity of the urban built-up area of the central Yunnan urban agglomeration is concentrated in the main urban area of Kunming City,the shift of the center of gravity is small,and the degree of spatial economic links between the city and the city is not the same.The urban built-up area of each single city is increasing year by year with different quantity and rate.The center of gravity of Qujing,Yuxi and Chuxiong are located in the main urban areas of each city respectively.The range of center of gravity transfer is relatively small in 21 years,and Kunming has the greatest radiation effect on Yuxi.(3)The CNLI light index and the comprehensive index system of urbanization level are calculated based on the results of the fourth chapter,and a urbanization level regression model is established.Since the high correlation coefficient of this model,the light index can reflect the urbanization level of the city.The result shows average light intensity in the central Yunnan urban agglomeration has the greatest impact on the urbanization level of each city in the development process.Overall,the urbanization level in all cities is increasing year by year,of which Kunming has the highest degree of development,Chuxiong Yi Autonomous Prefecture has the lowest degree of development.