Un modèle pour la croissance des systèmes urbains, la loi de la métropolisation / A growth model for urban systems, the metropolitan concentration law

摘要

In this paper, is described the law of métropolisation as a model of growth, produced from an harmonized data base about towns and cities in the world ;the measures concern 25 000 agglomerations (42,5% of the world population - 2,27 milliard of inhabitants) taken at five different periods (1950, 1960, 1970, 1980, 1990). Two main results are given. In the one hand, results and answers to the questions of the urban growth are presented. On the other hand, it shows the interest of an inductive method (from fact to the law). The accumulated and complete data gathered at the world scale and identifying all the possible space levels, even within the smallest (200 m more or less) allow to hold the two links which, in the long length duration, seem to resist to the disorders of history and geography, the local and the global.