Linking scales and urban network development

Comparative studies of urbanisation can be characterized by their emphasis on the quantitative and visual aspects of urban growth, which is amongst other things reflected in the analysis of spatial patterns and rates of urban population growth. The visual aspects relate both to the spatial realisation of the demand for urban land use and its functional variation. This emphasis can be understood from the perspective of the ongoing process of urban industrial growth in the industrialised countries during the 19th and most of the 20th century. Most of the concept and models we use have been developed during this period of urban transition and relate to this experience. However, in the last quarter of the 20th century this process came to an end as the urbanisation process in its present form was completed. This leads to the following questions. First, to what extent are the concepts and models derived throughout this period still valid? Second, if this is not the case, to what extent do they need adjustment and third, what kind of new approaches are required? In this paper the focus will be cities as part of an urban system and will deal with two issues, viz. the relation between spatial scales, i.e. vertical linkages and the relation between cities, especially focussed on their horizontal linkages or network characteristics. These two issues will be discussed against the background of the completion of three long-term developments: (1) the completed first demographic transition, (2) the completed process of industrialisation and (3) the completion of three infrastructural revolutions. This analysis will indicate the direction in which the environment has changed, the consequences of this change for the conceptualisation of the process of urbanisation and for the characteristics of the process it self. The consequences of these changes will be discussed using empirical examples from the Netherlands and other parts of Europe both for models of internal urban structure and for the city system at large. The classical unity between territory, economic and social functions is broken up and has lead to a decoupling of functions both in a spatial and in a functional sense. The latter has resulted in a process of spatial rebundling of activities. It will be argued that new rationalities are needed to understand the contemporary realisation of the spatial outcome of the demand for space use. In addition to this, it has also been argued that new and different types of uncertainties emerge. The latter are related to the increased importance of micro processes in the demand for space use. This in turn has consequences for spatial policy, as it will lead to considerable mismatches between national planning goals and actual realisations. It is suggested that a process approach is needed to deal with these uncertainties.