Scaling Laws and Urban Systems

This paper is a review of a few problems associated with the observation of scaling laws in urban systems. Two levels in the spatial organization have to be formalized, cities as systems and systems of cities. Both encounter problems of measurement, especially in the identification and delimitation of towns and cities. The problem of city sizes and its relation to urbanization processes have been conceptualized in connection with Pareto laws, central place theory, space-time transformations, and fractal geometry. All approaches raise the question of how the autonomy that characterizes the evolution of urban systems at a macro level can be realized, either by random growth, or optimization processes, or controlled by systems of social and spatial interactions at a micro-level.