The Research On Characteristics Of Urban Spatial Expansion Of Central And Southern Liaoning Province Urban Agglomeration Based On Nighttime Lights Data

With the development of GIS technology,remote sensing has played an important role in the research and application of various fields,such as the expansion of urban land use and land use type change monitoring.Especially the appearance of nighttime remote sensing data provides a new source of data for urban research.It more objectively reflects human activities.Urban agglomeration is the phenomenon of urbanization in the process of urban formation and development.It is the highest organizational form of the current stage of urban development and is the main aspect of urban research.Based on Central and southern Liaoning Province Urban Agglomeration as the research area,this paper use the nighttime light images,LandsatTM/ETM + image,and China City Statistical YearbookChina City Statistical Yearbook as the data source to study the Central and southern Liaoning Province Urban Agglomeration during 1992-2017 to study the urban expansion.The main contents and results of the research are presented as follows:(1)The multi-temporal nighttime light data was intercalibrated.The DMSP/OLS data has no on-board calibration,so it's lack comparability between data in different years.This paper determines the correctiom parameters of 19 years from 1992-2013 average nighttime light radiation calibration data on the basis of exieting research methods.Then the intercalibration was carried out for the multi-temporal nighttime lightimagery.(2)A SVM-based method was proposed to extract the shape and contour information of urban aera,and verify the feasibility.Using supervised classification result LandsatTM/ETM images and China City Statistical Yearbook data of SVM method in urban construction land results validate,the results show that using SVM method to extract information in cities and towns can be kept complete urban space form,and the extracted area is of high precision.(3)Urban expansion of China and typical urban agglomeration was analyzed for the past 25 years.In the past 25 years,the spatial pattern of Central and southern Liaoning Province Urban Agglomeration has undergone great changes,which gradually formed the Point-axis development model.In terms of the expansion strength,the extended strength is presented as the trend of "increase first-then decrease-then increase-then decrease".The center of gravity of the town shows a trend toward the southwest.(4)The driving factors and restrictive factors of urban agglomeration expansion are analyzed.It is found that the driving factors include the labor force,capital,innovation and other driving factors of the Douglas production function,as well as the driving factors such as the main functional area and the accessibility of traffic.At the same time,it also includes population aging and human resource loss,regional partition and space division,resource depletion problem,and insufficient constraints of urban hinterland expansion space constraints.In this paper,through a long period of time sequence of the nighttime light data to realize the dynamic monitoring of urban expansion,at the same time with the social and economic statistical data analysis of the driving force of the evolution of urban agglomerations better reveal the rule of urban expansion and the driving factors,so as to guide the reasonable layout and scientific planning of urban agglomerations,promoting regional economic and social sustainable development.Based on this,it is of great significance to study the spatial pattern evolution of urban spatial pattern of urban agglomeration in the new period in the new period by using night light data.