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Sustainable Development Goals are intrinsically competing, and their embedding into urban systems furthermore emphasises such compromises. When observed at the scale of systems of cities, such concern is considered as a series of innovations that challenges the adaptive capacity of urban systems. The spatial complexity, the non-optimal nature of such systems, and the multi-objective aspects of their agents, are among the reasons that raise difficulties when trying to adjust local policies through promoting innovation in order to satisfy at least a couple of SDGs simultaneously. As we lack enough empirical evidence, we propose in this paper to use a stylised simulation model for systems of cities, focused on innovation diffusion and population dynamics, to show how trade-offs may operate at such a scale. We proceed in particular to a bi-objective optimisation of emissions and innovation utilities, and show that no single urban optimum exists, but a diversity of regimes forming a compromise between the two objectives.

Created in 1996, Cybergeo, European Journal of Geography is native digital journal which was conceived from the start for publication in all European languages. In order to better promote its authors’ articles internationally, it is undertaking actions to improve and translate its metadata into English, Spanish and Chinese. CybergeoNet is a laureate of the AAP "Scientific Translations" launched in 2019 by the Ministry of Higher Education, Research and Innovation (MESRI) in France. It has developed an efficient, and quality, collaborative translation method that is transferable to other scientific journals published and managed by research laboratories. The aim is to ensure that authors and editorial teams become more competent in translation. A guide of good practices is proposed to the community. The impact of linguistic improvements made to the journal’s metadata is also measured with the consultation statistics provided by the OpenEdition platform. All documents are freely available online.

China’s urbanization has followed an original trajectory including during the last four decades a strongly planned economic development. The policy of creating Economic Development Zones is one of the major tools in use for modernizing the economy. We try here to measure the relationship between Economic Development Zones and urban demographic growth at disaggregated geographical levels (districts and urban agglomerations). An original database documenting EDZ characteristics and location has been collected at district level and coupled via a GIS to the ChinaCities database. We explore both to what extent the selection of places where EDZ developed is linked with the former hierarchical and spatial pattern of Chinese urban system and what impact the EDZs have had on urban development. We conclude that the selection of places mainly guided from national policies followed a hierarchical diffusion of this “innovation” in the Chinese urban system. Measuring the impact of that policy on urban growth however leads to the introduction of the hypothesis that other policies mainly inspired at local level may as well have widely influenced the spatial distribution of urban growth.

For the first time the systems of cities in seven countries or regions among the largest in the world (China, India, Brazil, Europe, the Former Soviet Union (FSU), the United States and South Africa) are made comparable through the building of spatio-temporal standardised statistical databases. We first explain the concept of a generic evolutionary urban unit (“city”) and its necessary adaptations to the information provided by each national statistical system. Second, the hierarchical structure and the urban growth process are compared at macro-scale for the seven countries with reference to Zipf’s and Gibrat’s model: in agreement with an evolutionary theory of urban systems, large similarities shape the hierarchical structure and growth processes in BRICS countries as well as in Europe and United States, despite their positions at different stages in the urban transition that explain some structural peculiarities. Third, the individual trajectories of some 10,000 cities are mapped at micro-scale following a cluster analysis of their evolution over the last fifty years. A few common principles extracted from the evolutionary theory of urban systems can explain the diversity of these trajectories, including a specific pattern in their geographical repartition in the Chinese case. We conclude that the observations at macro-level when summarized as stylised facts can help in designing simulation models of urban systems whereas the urban trajectories identified at micro-level are consistent enough for constituting the basis of plausible future population projections.Keywords: urban system, Zipf's law, Gibrat, cities trajectories, BRICS

In May 2016 Cybergeo, European Journal of Geography celebrated its 20 years anniversary at the headquarters of CNRS (French National Center for Scientific Research). It was the first purely electronic journal in social sciences. Cybergeo is at the forefront of the movement defending free access for the dissemination of scientific knowledge. Its 20 years’ experience brings the proof of the viability of an open model for the diffusion of scientific information whose quality is controlled by the global scientific community. It also does confirm the strong increasing impact of open access to science when it is supported by a constant attention to innovation.

In May 2016 Cybergeo, European Journal of Geography celebrated its 20 years anniversary at the headquarters of CNRS (French National Center for Scientific Research). It was the first purely electronic journal in social sciences. Cybergeo is at the forefront of the movement defending free access for the dissemination of scientific knowledge. Its 20 years’ experience brings the proof of the viability of an open model for the diffusion of scientific information whose quality is controlled by the global scientific community. It also does confirm the strong increasing impact of open access to science when it is supported by a constant attention to innovation.