Spatial configuration has a significant impact on the efficient and balanced development of cities and regions. Following the rapid expansion of urban areas and the development of transportation and communication technologies, polycentricity has become the dominant trend of spatial restructuring in many cities and regions. Meanwhile, it has been adopted widely as an important tool of spatial configuration in urban and regional planning.
However, the concept of "polycentricity", despite its wide usage in the literature, remains confusing and in needs to be clarification. Moreover, there is no consensus on the prevalence and advantages of the polycentric form of city and regional spatial structure compared with those of the monocentric counterpart.
This article reviewed the research related to polycentricity in Chinese and international literature to get a systematic comprehension of this concept. First, it analyzed the connotation of intra- city and inter- city polycentricity, morphological and functional polycentricity based on the definition of research scale and importance of centers. Second, this article reviewed the evolution mechanism of the polycentric city and urban region from the perspectives of the generation of new centers and the integration of existing centers. Third, it summarized the various tools of identifying and measuring polycentricity, the development trend and performance of city and regional spatial structure.
We recommend the following: 1) Defining polycentricity clearly and measuring it appropriately with some new data and tools to make the results more accurate and comparable. 2) Comparing the variation of city and regional spatial structures and analyzing the causes from the perspectives of agent's decisions and the comprehensive effect of the spatial distribution of various economic factors. 3) Evaluating the performance of polycentricity comprehensively, which means taking the environment and socioeconomic background of cities and regions into consideration when exploring the advantages and disadvantages of polycentricity in multiple perspectives.
