La modélisation des réseaux urbains

1994Modelling urban networks. The concept of urban network is frequently used in France, compared to English-speaking world where the expression of urban system is preferred. We review here the main conceptions and types of studies which documented the concept, during the fourty years period between 1950 and 1990. In a first step, until the 60's, the uses of the term network were mainly metaphoric in the sense that the properties of the nodes were studied more than the edges. Works related to central place theory exemplified hierarchical distributions in size, functional diversity and spacing of cities. The second period made a more explicit use of the network, both in analysing the communication or migration flows between cities and by suggesting that networks were a more efficient and democratic form of organisation than hierarchies (for instance within the DATAR's policy promoting the “réseaux de villes”). In a third set of references, including the dynamic modelling of urban systems, the network becomes implicit again (it is represented in the models for instance through processes of diffusion, competition or comparative urban dynamics). We conclude by suggesting that, despite a frequent lack of empirical data, an explicit consideration of network organisation in the dynamic models could be interesting