Remote sensing monitoring and spatiotemporal characteristic analysis of urban construction land expansion in the urban agglomerations of China in the past 30 years
The analysis of the spatial and temporal changes of urban agglomeration construction land expansion is highly significant for optimizing the spatial pattern of urban agglomerations and promoting regional coordinated development.In this study,19 urban agglomerations in China are selected as the research object.Based on remote sensing image data of medium-scale resolution in China from 1990 to 2020,the boundary vector of urban concentrated construction areas is extracted from the actual construction of a city by using the method of human-computer interaction.Results are compared with those of other related studies,and research is conducted from the aspects of urban agglomeration expansion process,development stage,expansion mode,and center of gravity migration law.The results show the following.(1)Compared with other research results,the urban boundary of this study exhibits higher accuracy and reliability.It is also closer to the real situation of a city.(2)In the past 30 years,the urban scale change curve of 19 urban agglomerations in China generally presents an"S"type,and the expansion process of urban agglomerations can be divided into three periods:slow,rapid,and stable expansion.Eastern urban agglomerations entered the rapid expansion period about 10 years earlier than western urban agglomerations.Most urban agglomerations entered a period of steady expansion after 2015.(3)By 2020,19 urban agglomerations were in a high-level development stage,and the coordination degree of spatial expansion between internal central and peripheral cities was continuously improved.From the perspective of spatial distribution,70％of the urban agglomerations in the eastern region are in the stage of decentralization,56％of the urban agglomerations in the western region are in the stage of agglomeration attenuation,and eastern urban agglomerations are generally in a higher level of urban agglomeration development stage.(4)Based on the expansion scale of urban agglomerations in different directions,the spatial expansion modes of 19 urban agglomerations in China can be divided into circular,fan-shaped,and axial expansions.The spatial expansion mode is closely related to the number,location,and influence of core cities within an urban agglomeration.In addition,topographic conditions pose certain restrictions on the expansion direction of urban agglomerations.(5)The gravity center migration trajectories of urban agglomerations are different,and expansion direction may be affected by various factors,such as the location of core cities,the construction of new areas,traffic conditions,and terrain conditions.From the perspective of change in the center of gravity of urban agglomerations,the center of gravity of 84％of urban agglomerations was relatively stable in the past 30 years,i.e.,basically located in the core city or the same city adjacent to the core city.The core city of urban agglomerations is attractive,and the expansion of the construction scale of a peripheral city is relatively average.The results of this study provide intuitive and accurate data for the study of urban expansion in China.Long-term and high-precision monitoring of urban construction scale can fully reflect the development process of urban agglomerations.
万方数据
维普
