Research On Boundary Expansion And Driving Forces Of Built-up Area

At present,urbanization has gradually become an important social and economic phenomenon,gathering a variety of advantageous resources,and promoting the rapid expansion of urban land in various countries and regions.However,with the rapid growth of urban land,there are many problems,such as the imbalance of urban and rural development,the protection of ecological environment,the decline of land carrying capacity and so on.Therefore,it is of great significance to analyze the boundary expansion and driving forces of urban built-up areas in terms of land space planning and sustainable development.In this thesis,8 districts and 2counties of Jinan City are taken as the research object,and the corresponding research is carried out with a variety of data(1)Urban built-up area boundary extraction.Firstly,based on the Landsat Image data,this thesis uses the support vector machine supervised classification method for land use classification,extracts the construction land and merges it into the built-up area;secondly,based on the DMSP/OLS night light data,NPP/VIIRS night light data and statistical data,the threshold dichotomy method and high-resolution image comparison method are used to preliminarily extract the built-up area;finally,the urban built-up area boundary is extracted by data fusion To further improve the accuracy of built-up area boundary extraction.The boundary extraction of urban built-up area shows that the accuracy of this thesis is more than 90%,which can be used to analyze the boundary expansion and driving force of urban built-up area.(2)Analysis of the spatial and temporal characteristics of urban built-up area.According to the boundary of urban built-up area extracted in the previous thesis,the temporal and spatial characteristics of urban built-up area boundary expansion are analyzed.The time sequence characteristics of urban built-up area boundary expansion are analyzed from the aspects of land use growth,expansion speed and expansion intensity.The total area growth of the study area is287.33~2,and the area of each district and county gradually increases during this period.In the analysis of expansion speed,the expansion speed of the study area continues to increase,among which Licheng District has the largest expansion speed,Pingyin County and Pingyin County have the largest expansion speed The results show that the expansion speed of Shanghe county is the lowest;in the analysis of expansion intensity,the total expansion intensity of the study area changes from low intensity expansion to medium intensity expansion,and the expansion intensity of Jiyang district and Zhangqiu district gradually increases.The spatial characteristics of the boundary expansion of urban built-up area are studied from the change of gravity center,spatial orientation and morphological characteristics.From the analysis of gravity center change,the gravity center of the central urban area of the study area is distributed in Lixia District and gradually moves to the East in recent ten years.The spatial orientation characteristics show that the central urban area expands greatly in the east-west direction,and Zhangqiu district and Jiyang District expand to the southwest.The analysis table of morphological characteristics In recent ten years,the spatial expansion of the study area was mainly outward expansion,and the boundary shape of the built-up area was unstable.(3)Research on the driving force of urban built-up area boundary expansion.From the perspective of single factor analysis,using a variety of data to assist the analysis of urban boundary expansion factors in the study area,the study found that nature,population,economy,transportation policy factors have a certain impact on the built-up area boundary expansion.Multi factor analysis adopts principal component analysis and stepwise regression analysis.The results show that economic growth and perfect transportation facilities are the main factors to promote the boundary expansion of built-up area.(4)Land use scale prediction of the built-up area in the study area.According to the main driving factors of the previous analysis,this thesis selects the strong driving factors to build the grey GM(1,N)model to predict the land use scale of the built-up area from 2021 to 2025.