Spatial heterogeneity of human settlements suitability from multidimensional perspectives in 31 provincial capital cities of China

Human settlements suitability (HEI) is the foundation of urban development and is critical for achieving sustainable urban development and the United Nations’ development goals. Existing studies on HEI have paid little attention to the characteristics of HEI at different urban scales and climate zones or to the spatial differences along urban–rural gradients (URGs). This study used multisource data to select natural and humanistic elements and constructed a framework for evaluating the HEI of 31 provincial capital cities in China, aiming to address the limitations. The results showed that: (1) the HEI of provincial capital cities in China ranged from 0 to 51.54, showing an overall increasing trend from northwest to southeast, and the HEI of coastal cities was considerably higher than that of inland cities. (2) The HEI of built-up areas at different urban scales conformed to the trend of gradually increasing with the expansion of urban scales, with obvious differences in the average HEI of built-up areas in different climate zones, shown as follows: tropical monsoon > subtropical monsoon > temperate monsoon > plateau mountain > temperate continental. (3) When the distance from the city centre increased, provincial capital cities showed a gradually decreasing trend in HEI, albeit with varying degrees of decrease. Further, the discrepancies in the HEI along the URGs were closely related to urban scales and climate zones. Scientific and objective evaluation of HEI is a prerequisite for optimising the spatial development patterns of national spatial planning. Based on the multidimensional perspectives of different urban scales, climate zones, and URGs, the breadth of HEI research has been enriched, which is of strategic significance in governing urban spatial planning and augmenting urban competitiveness.