Characterising spatial and temporal patterns of urban evolution in Sub-Saharan Africa: The case of Accra, Ghana

Abstract

Rapid urbanisation and globalisation are creating relentless spatial transformation across the globe. There is a growing interest in understanding and conceptualising the emergent and often contested spatial morphologies and typologies in cities as they mediate the competing demands of global and local forces. This paper examines spatial and temporal development patterns in a Sub-Saharan Africa context using Accra, the capital and rapidly growing city of Ghana, as case study and explores the emerging urban form. By classifying Landsat satellite images (1986–2017) and using landscape/spatial metrics to characterise Accra’s spatial development along four concentric rings, we find growing complexity and fragmented spatial growth patterns in Accra. Despite the spatial fragmentation, a Contiguity Index of 0.64, 0.49 and 0.56 for 1986, 2000, and 2017 respectively show that Accra’s urban form is not amorphous nor polycentric but monocentric. The study demonstrates that using landscape metrics to characterise spatial development patterns under buffer zones leads to better understanding of the temporal and changing form of the city under various conditions. We reflect on the implications of these findings for urban policy and planning in Accra and other similar Sub-Saharan African cities.