City components–area relationship and diversity pattern: towards a better understanding of urban structure

Abstract Optimizing the distribution of urban facilities with scarcity urban land can improve the fairness of residents’ access to services. The lack of assessment on the diversity pattern of city components (i.e., urban facilities of all types of industry related to socioeconomic activities) limits the reasonable planning of emergence polycentric cities. Therefore, we took Shanghai, Hangzhou, and Xi’an City in China as cases. A total of 407,652 city components were analyzed to assess the spatial pattern of components diversity through the nested sampling design and diversity assessment methods of ecology. Results showed that the city components–area relationship (CAR, i.e., the number of component types increases as the sampled area) had a power-law growth with land area, which can be a reference to construct reasonable urban sub-centers with sufficient components diversity. The individual density and components richness decreased on the urban–rural gradients, which significantly positive related to population density, land price, and building covers. Furthermore, the similarity of component types decreased with increasing geographic distance, indicating that there is an agglomeration distribution of industrial diversity. This study provides a new insight into applying ecological methods to explore the urban structure, and further supports the sustainable planning and development of cities.