Spatio-temporal process and mechanism analysis of Shanghai's urban expansion in 1843-2020
Shanghai is one of the most significantly urbanized cities in modem China,and its urban spatial pattern and urban area have changed dramatically since its opening up(1843-2020).Reconstructing and analyzing the expansion process of Shanghai has great importance toward attaining a deeper understanding of China's urbanization.This study collected multi-source and multi-precision urban spatial data such as old urban maps,topographic maps of the Republic of China(1912-1949),declassified images from the U.S.military(KeyHole),and remote sensing data(Landsat),and reconstructed a long time series of urban built-up areas,and finally examined the evolution process and driving forces of the spatial structure of Shanghai.The results show that:(1)Since 1843,the area of urban built-up areas increased tremendously,with a total expansion of about 1453 times,and the expansion rate and expansion intensity also changed drastically.(2)The overall change trend of compactness is decreasing,and the fractal dimension shows a certain cycle.(3)The center of gravity of the built-up area in different periods showed a trend of developing first to the north and then to the south,and the most important direction of expansion was southwest and west by south.(4)The urban change was complicated by multiple driving factors:the natural location established the prerequisite for the development of Shanghai as a port city;as the most fundamental driving force,social change and policy determined the main direction of urban development at different stages;the spatial agglomeration of industry and trade is the direct cause of the formation and expansion of cities;population migration also injected new impetus into the urbanization;transportation,as an urban infrastructure,has been used to strengthen the connection between the city's external and internal regions.This study clarifies the processes and mechanisms of urban expansion in Shanghai and provides historical knowledge and scientific support for a deeper understanding of urban change and the evolution of the human-land relationship.Moreover,the ways in which a set of general data with a wide coverage and high resolution can be used for the study of the spatial and temporal processes of urban expansion on a centennial scale are discussed,which is quite instructive for understanding the pre-remote sensing era and developing longer time series.
urban expansionShanghaihistorical geographylong time seriesold maps
NETL
NSTL
万方数据
