History, politics, environment and urban forms in Africa

The first part of Chapter 3 analyses the demographic, political and environmental factors that influence urban growth in Africa. Africa has transitioned from a period of demographic stagnation dating to the pre-colonial era to a period of positive growth in the colonial era, followed by exponential growth after independence. Since the beginning of the 2000s, globalisation has left its mark on settlement patterns. Political conditions have shaped urban phenomena — the impact of urban planning (or its absence) is visible in satellite imagery, and administrative boundaries often do not match those of existing agglomerations. Finally, environmental constraints like the availability of water or land have major influences on urban growth, as demonstrated by the agglomerations of the Nile River valley or in Rwanda. In the second part, this chapter highlights different “spatial attractors” (points, lines and surfaces) used to model urban dynamics. The analysis of growth factors and modelling reveals new aspects of urban growth in Africa: the increasingly blurred distinction between urban and rural, dispersed urbanisation and chaotic forms of agglomeration.