Research on the Spatiotemporal Coupling Characteristics between Urban Population and Land in China Based on the Improved Coupling Model of Polar Coordinates

Scientific quantitative measurement of the coupling relationship between urban population (UP) and urban land (UL) is conducive to promoting intensive land use, coordinated human–land development, and new urbanization development. This research proposed an improved coupling model of polar coordinates to study the spatiotemporal coupling characteristics between UP and UL at the prefecture-level city scale in China from 2010 to 2020. The study results include the following: (1) The growth rate of UL in China’s prefecture-level cities was higher than that of UP. The per capita urban land (PUL) was always within the ideal range, and the dynamic human–land coupling state remained reasonable. (2) The UP, UL, and dynamic human–land coupling rationality in China showed characteristics that were high in the east and low in the west. The PUL showed characteristics that were high in the northwest and low in the southeast. (3) This study divided China’s prefecture-level cities into four regions according to the coupling characteristics and formulated regionally differentiated optimization strategies. In summary, this study carried out a more scientific and reasonable quantitative measurement of the coupling relationship between UP and UL in China, resulting in a more reliable and targeted formulation of optimization strategies.