Analysing the consistency between built-up areas and human activities and the impacts on the urbanization process: a case study of Zhengzhou, China.

Urbanisation is accompanied by drastic urban sprawl and populations gathering in cities. The new urban districts in China have gradually become the most effective form of built-up area expansion, but the corresponding human activities within these built-up areas have not increased at the same rate, which has led to the emergence of urbanisation-related problems, such as ghost cities. However, few studies have focused on the evolution of this inconsistency within a city, especially at multiple scales. Based on Landsat images and the Defense Meteorological Satellite Programme-Operational Linescan System (DMSP-OLS) data, our study calculated the barycentre, the agglomeration degree and the consistency index to quantitatively analyse the spatio-temporal consistency between built-up areas and human activities within a city from 1993 to 2013. A mainstream urban example in China, Zhengzhou, which accepted financial and policy support from the government and underwent rapid urbanisation, was chosen as a case study. The results of this study showed that (1) the consistency between built-up areas and human activities was characterised by an approximately S-shaped curve that divided the city's development into three stages, namely, relative stability (1993–1998), rapid development exhibiting inconsistency (1998–2008) and the optimisation and matching of spatial factors (2008–2013); (2) the inconsistency stage had two diametrically opposed patterns: the increase in human activities lagged behind the expansion of built-up areas, and the opposite occurred in older areas, which resulted in the emergence of ghost cities in new districts and crowded populations in the old cities; and (3) the inconsistency stage occurs easily; thus attention should be paid during the promotion of urbanisation processes in rapidly developing cities such as Zhengzhou; however, as the urban population increases, under economic development and a policy of unceasing expansion, the area of inconsistency was mitigated after 2010. Our findings illustrated the influence of consistency on built-up areas and human activities in terms of coordinated development within cities and provided a better understanding of the urbanisation process in Chinese cities. [ABSTRACT FROM AUTHOR]