The spatial patterns and processes of cities can be described with various entropy functions. However, spatial entropy always depends on the scale of measurement, and it is difficult to find a characteristic value for it. In contrast, fractal parameters can be employed to characterize scale-free phenomena and reflect the local features of random multi-scaling structure. This paper is devoted to exploring the similarities and differences between spatial entropy and fractal dimension in urban description. Drawing an analogy between cities and growing fractals, we illustrate the definitions of fractal dimension based on different entropy concepts. Three representative fractal dimensions in the multifractal dimension set, capacity dimension, information dimension, and correlation dimension, are utilized to make empirical analyses of the urban form of two Chinese cities, Beijing and Hangzhou. The results show that the entropy values vary with the measurement scale, but the fractal dimension value is stable is method and study area are fixed; if the linear size of boxes is small enough (e.g., <1/25), the linear correlation between entropy and fractal dimension is significant (based on the confidence level of 99%). Further empirical analysis indicates that fractal dimension is close to the characteristic values of spatial entropy. This suggests that the physical meaning of fractal dimension can be interpreted by the ideas from entropy and scaling and the conclusion is revealing for future spatial analysis of cities.

This study focuses on state-led urbanisation in the Chinese context by examining the effects of urban administrative level upgrading on urbanisation and urban development. We argue that urban administrative level upgrading is an important policy instrument in China that empowers cities to play a leading role in driving national and regional economic development. However, there is a lack of systematic empirical investigation to determine whether the objectives of urban administrative level upgrading have been achieved. Using a quasi-experimental method that combines propensity score matching with the difference-in-difference approach, we thoroughly examine the effects of county- to prefecture-level city upgrading and county to county-level city upgrading on the development performance of cities. The results confirm that county- to prefecture-level city upgrading can positively lead to a significant increase in urban population growth and fiscal revenue in a few years after upgrading, although this may not necessarily lead to rapid industrialisation. However, the same is not true for county to county-level city upgrading. This difference may be because counties and county-level cities are at the same administrative level, whilst prefecture-level cities are at a higher administrative level compared with county-level cities and counties. The results indicate that China’s administrative division system, although restructured, retains hierarchical and level-based structure in the post-reform period. We highlight the continuing strategic role of the Chinese state by establishing new scales and arenas and adjusting administrative structures to promote urban development.

Internal migration is critically important in China, where the fertility rate is declining and international immigration is under strict control. This study explores the massive population movement in China, examines the migration pattern of non- hukou migrants, 2010–2015 and 2014–2015 migration patterns through the urban hierarchy of the urban system using migration trajectories derived from the 2015 One Percent Population Sample Survey. Results reveal an emerging reversal from a predominantly upward pattern (e.g. most of the net flows move to high-level cities) to a downward one (e.g. from super-large/extra-large cities to large cities) in the recent migration trend. Regional disparities are significant. An upward and eastward tendency still dominates in the western, central and northeastern regions, whereas a downward and decentralised tendency has been initiated in the eastern region. The causes for the structural change include common factors found in developed countries, such as the influence of age and life courses. The age structure of China’s population caused by the ‘one-child’ policy weakened the upward momentum and led to a strengthening downward trend in the current migration pattern. The contextual and institutional factor hukou also has a significant effect on people’s migration directions. Hukou attracts people to move up or down the hierarchy to their registered place or where they can acquire registration. The characteristics of registered migrants reflect the different criteria of cities in granting hukou.

This paper examines onwards migration patterns and the factors that influence them in urban China. In contradiction to Ravenstein’s laws of step migration, we argue that movement up the urban hierarchy does not dominate onwards migration in the Chinese context. Using the 2017 China Migrants Dynamic Survey, we model how past migratory experiences intersect with migrants’ demographic and socio-economic characteristics to explain the stay-versus-move decision and who moves up as well as who moves down within China’s urban hierarchy. The general pattern of China’s domestic migration is a movement up the urban hierarchy in the first migration and a movement down in onwards migration. We identify a transition-levels effect whereby the larger the difference between the hukou-registered place and the first migration city in the urban hierarchy, the greater the probability of onwards migration, with the effect manifesting most strongly for less-educated, mid-age (the 1970s and 1980s birth cohorts) migrants with rural origins. As to onwards migration direction, mixed results were found for migrants’ demographic and socio-economic characteristics whereas educational level and the transition-levels effect are both highly predictive of movement up and down the urban hierarchy. Our findings suggest that ‘jumping too high’ in previous migration(s) predicts a greater likelihood of moving down the urban hierarchy in response to insurmountable obstacles to settling in cities classified as large and above. Our research advances migration scholarship by considering the multipolar nature of onwards migration and offering an integrated approach to analysis that foregrounds the causes and effects of multiple-step migration.

The evolution of city size distribution in China has gained a great deal of scholarly attention. However, little is known about the effect of economic transition on the reorganization of city size distribution in China. Using an urban hierarchy with cascade structure model, we decompose Zipf’s law into two exponential functions that provide a new way of examining the dynamic processes of urban system evolution. This study aims to investigate the dominating latent forces that affect China’s city size distribution through mathematical modeling of the hierarchical scaling laws based on census data of 1982, 1990, 2000, and 2010. A number of features of China’s city size distribution are found. First, the size distribution of Chinese cities displayed a clear trend of evolving toward the Zipf distribution, which is the result of economic transition from planned to market. Second, the rank-size pattern still deviates slightly from the standard Zipf distribution, as indicated by the narrow scaling range and departure of the scaling exponent from the theoretically expected value. We argue that the top-down state regulation is a critical cause of deviation of China’s city size distribution from Zipf’s law.