Study On Evolution Of Urban Spatial Form And Identification Of Functional Zones Of Jilin City

At present,the land space planning work carries out,and the study of urban spatial form and structure is crucial to the future development of urban space.It was clearly pointed out the work is to optimize the layout and form of urbanization and improve the functions of the central urban area.It was emphasized that the key to forming a sustainable land and space pattern was to identify and divide the leading functions of different urban land and optimize the layout of urban functional areas.As a provincial sub-central city,Jilin has natural advantages such as mountains and rivers,ice and snow,agriculture,and a strong industrial base with rich industries and categories.However,in the process of urbanization,problems such as industrial decline,unreasonable urban structure,low land use efficiency,and ecological security damage have occurred in succession.Therefore,based on the overall development of territorial space planning and the overall revitalization of the northeast,starting from the process of urban expansion and internal functional areas,it is of great theoretical and practical significance to study the spatial evolution of the city for the rational planning of urban spatial layout and regional sustainable development,and to build Jilin into an important central city in the Northeast.Therefore,this paper selects Jilin City as the research area,and the main research results and conclusions are as follows:(1)Research on urban spatial expansion and influencing factors.Using the resources and environmental science data of the Chinese Academy of Sciences in 1990,2000,2010 and 2020(http://www.resdc.cn/)and basic geographic information data,using the methods of expansion speed and strength,fractal dimension,barycenter coordinate transfer index,sector analysis and other methods to analysis the spatial and temporal expansion characteristics of the built-up areas in Jilin city from 1990 to 2020.The ultimate goal is to analyze the driving and limiting factors that affect the spatial expansion.In the time dimension,the expansion speed of urban land in Jilin city has been relatively slow in the past 30 years,and only slightly faster in 2010-2020;In the spatial dimension,Jilin city mainly expanded to the south,followed by the west.Extensive expansion has resulted in complex urban morphology of Jilin city,and the overall stability and compactness are also poor;Jilin urban expansion is affected by multiple factors.The positive factors mainly include urban planning,traffic guidance,industrial development.Limiting factors include natural factors,ecological protection,population loss.(2)Identification of land use function in the central urban area of Jilin City.Combined with POI and road network data,the TF-IDF statistical method is used to build a land use function identification system for the central urban area of Jilin,and complete the identification of the current land use function.Finally,compare the recognition results with the planning map of the central city of Jilin,and use the confusion matrix to calculate the overall accuracy and Kappa coefficient for accuracy test.The overall accuracy reaches80.84%,with high accuracy and reliable conclusion.(3)Evaluation and analysis of spatial characteristics and pattern of urban functional land.The result of land use function identification shows that the central urban area of Jilin City is dominated by public service and traffic land,the number and distribution of functional areas in different jurisdictions are significantly different.Using information entropy,balance degree,dominance degree,and location entropy indicators to carry out a composite analysis of the functional elements of the four districts,it is concluded that the four municipal districts in Jilin City have uneven distribution of land use and there is optimization space in the structure of the functional areas.(4)Summarize the existing problems in the urban form and spatial structure of Jilin City,reasonably arrange various types of construction land,pay attention to ecological protection,increase the proportion of green space and open space,and strengthen the construction of green space.Improve the infrastructure of each district in the central urban area,strengthen the connection between each cluster on the basis of the "two axes and three clusters" pattern,and create the urban spatial form of "cluster layout,multi-center and multi-region coordinated development".