| description abstract | The synergistic development of metropolitan areas led by megacities is considered a driving force in achieving regional coordination and the high-quality development of urban agglomerations. Extant studies have often neglected the spatial structure of metropolitan areas under the guidance of megacities. This study sought to explore the radiation effect of central cities, the development capacity of metropolitan subcentral cities, and the intermediary role of metropolitan hub cities in the metropolitan area. Based on the modified gravitational model and social network analysis, we constructed a spatial connection network of the Shanghai metropolitan area with districts and counties as the basic research units and analyzed the characteristics from two perspectives: network hierarchy and network structure. Our results indicated the following: (1) The connection strength of the metropolitan area decreased from the center of the network to the periphery. (2) The polycentric pattern was gradually forming, but a significant gap remained between the radiation range and capacity of central and subcentral cities. (3) The clustering phenomenon in the metropolitan area was significant, and the degrees of internal connection and external radiation ability of each subgroup differed. (4) The core–edge structure as obvious, but its intermediary role in the network was relatively weak. Our findings revealed the spatial relationship pattern of metropolitan areas led by megacities and have implications for formulating scientific policies to promote the coordinated spatial development of metropolitan areas and the high-quality development of urban agglomerations. A high-quality urban agglomeration is highly significant, and coordination and balanced development among cities has become a pressing need. In recent years, many scholars have researched how to improve the quality of urban agglomeration development. The construction of metropolitan areas—the basic unit of urban agglomeration—plays a strategic role in urban agglomeration. Accordingly, analyzing the spatial connection networks in metropolitan areas led by megacities is necessary. In response, this study explored the network hierarchy and structure of a notable metropolitan area led by megacities, the Shanghai metropolitan area, to uncover valuable findings about the radiation effect of central cities, the development capacity of metropolitan subcentral cities, and the intermediary role of metropolitan hub cities in promoting the coordinated development of metropolitan areas. These findings offer useful insights for policymakers seeking to promote the coordinated spatial development of metropolitan areas, optimize their spatial structure, and promote high-quality urban agglomeration. | |
