Spatiotemporal Evolution Of Construction Land Expansion And Scale Structure In Guanzhong Plain Urban Agglomeration During 1990–2020

Urban agglomerations are the main form of promoting the development of urbanization in China,and the main bearing space for human activities and resource concentration.In the future,China's urbanization process will continue to advance,and it is expected that the urbanization rate will rise to 75%by 2035,the land security pattern and ecological environment of urban agglomeration areas will face a major test.It is a great significance to study the spatial temporal expansion of the construction land and the evolution of urban scale structure in urban agglomeration for the future spatial planning and governance and sustainable development of urban agglomeration areas.Exploring and summarizing the temporal and spatial laws of the formation and evolution of urban agglomerations can help to provide empirical references for the planning of urban agglomeration construction and ecological environment governance in China,and provide Chinese experience and evidence for the development of dense urban areas in the world.The newly issued"Guanzhong Plain Urban Agglomeration Development Plan"in 2018 has made the Guanzhong Plain urban agglomeration widely concerned by the scientific community.At this stage,there are a large number of foundations for theoretical and empirical research on the development of urban agglomerations.The mature urban agglomerations such as the Yangtze River Delta,the Pearl River Delta urban agglomeration,and Beijing-Tianjin-Hebei have provided a good model for the development and construction of urban agglomerations in other regions.However,the urban agglomeration in the western region has not yet fully exerted its role in leading regional radiation.The promulgation of the"Development Plan for the Guanzhong Plain Urban Agglomeration"is conducive to leading the development and opening up of the western region in China.Based on the current development background of China's urban agglomerations,this paper uses multi-temporal remote sensing image data and socio-economic statistical data to quantitatively analyze the scale,speed,intensity,and mode of the expansion of construction land space among cities of the Guanzhong Plain urban agglomeration since1990.The evolution process of the center of gravity and the characteristics of spatial agglomeration,and further review and analysis of the evolution process of the hierarchical scale structure and the coordination of human-land development in the urban system during the urbanization process,and summarizes the spatial and temporal characteristics of the development of the Guanzhong Plain urban agglomeration in the past 30 years And internal laws,which make up the research gap on the spatial and temporal evolution of the construction land of the Guanzhong Plain urban agglomeration,with a view to providing a reference for the future development planning and spatial governance of the Guanzhong Plain urban agglomeration.The main conclusions are as follows:(1)The construction land of the Guanzhong Plain urban agglomeration has continued to expand since 1990,and the regional land use pattern has undergone dramatic changes.The total construction land in the study area has increased by 2818.926km~2in the past 30 years,an increase of 87%.The construction land in the three phases experienced an expansion process from slow to fast to high speed.The growth rate of construction land is different between provinces and cities.The scale of construction land expansion shows the characteristics of"central>eastern>western";(2)The spatial expansion pattern of construction land in the Guanzhong Plain urban agglomeration has not changed significantly since 1990.The"spreading"expansion has always played a leading role,and the"outlying"and"filled"expansion has a low contribution value to the overall;(3)From 1990 to 2020,The center of construction land in the Guanzhong Plain urban agglomeration tends to shift from“east to west”,and the trend from“north to south”is weak.The process of spatial expansion of construction land in the northwest is slow and its share in overall construction land is small,but Over time,the difference between the expansion of urban agglomeration construction land has gradually narrowed.(4)During the study period,the spatial concentration of the construction land in the Guanzhong Plain urban agglomeration gradually increased,and the spatial pattern of“high and high agglomeration in the middle and eastern regions of the urban agglomeration and low and low agglomeration in the less developed regions and counties in the northwest and southwest”was basically formed.The phenomenon of polarization in the spatial growth of land use is outstanding;(5)During the study period,the rank-scale distribution structure of the city system of the Guanzhong Plain continued to be optimized,and the development of the urban system was relatively complete.However,the development of low-order cities is slightly weak,and the overall size and structure of the urban system presents a development trend from decentralization to concentration to decentralization;(6)The growth of the permanent population and construction land in the Guanzhong Plain urban agglomeration follows the law of allometric growth,and the development of man and land After experiencing the evolution process from the same speed to the positive all-speed growth,the development of the urban agglomeration is still in the stage of scale expansion.The growth of construction land in the later period is relatively extensive,and the coordination between population and construction land is poor.