Progress of urban polycentricity research and planning practice in the context of spatial restructuring

Abstract

The increasing globalization has led to significant transformations in the world's economic and political landscapes, with most countries and regions undergoing socioeconomic transitions and spatial reconfigurations. In this context, polycentric patterns have become prominent representations of urban landscapes, and scientific cognition of the urban polycentric evolutionary processes and planning practices is instrumental in understanding the development logic of China during its economic transition. This article reviewed existing literature on the measurement, mechanism, performance, and planning practice of polycentric urban development and discussed its policy implications. The definition of polycentricity covers three dimensions—morphological polycentricity and functional polycentricity reflect urban polycentricity based on static and dynamic perspectives, respectively, while governance polycentricity involves cooperation in strategic planning decisions and policy implementation. The measurement of urban polycentricity is first based on the identification of centers and sub- centers to further measure the degree of polycentric development in different dimensions. In terms of driving mechanisms, the formation of polycentric spatial structure results from the tradeoffs between market forces and government planning interventions and is also the spatial manifestation of the intertwining socioeconomic development and institutions, which is triggered and promoted by different leading factors. Notably, political power from the local institutions is a critical driving force shaping polycentric urban development. Research on the performance of polycentricity shows that polycentric development strategies may bring certain negative externalities at the practical level while optimizing spatial organization, and further evaluation of the importance and rationality of polycentricity is worthy of in- depth consideration. In terms of planning practice, polycentric development is a key measure for central and local governments to carry out spatial governance and achieve coordinated development, but the effectiveness of planning implementation is limited. In the future, emphasis should be placed on the innovation of analytical and theoretical frameworks of polycentric research, especially considering the development background of China. Also, as open data gets more widely available, scholars can employ multiple data sources to examine polycentric urban development at different scales and in different dimensions. At the same time, attention should be paid to the mechanism of the formation and evolution of polycentric spatial structure, the multiple performances, and the integration and conflict in multi-level governance. In this way, it assesses whether polycentric development can be used as a tool for strategic spatial planning and whether it can facilitate achieving a balance between space supply and demand while maximizing overall benefits, thus leading to effective spatial governance and regulation practice.