An anatomy of urbanization in sub-Saharan Africa

This paper analyzes urbanization patterns across Sub-Saharan Africa circa 2015 using a dartboard algorithm and high-resolution gridded population data to delineate urban areas and urban cores, cities and their population centers, and towns. Key empirical regularities are presented regarding urban hierarchies and internal city structures. Urbanization rates often exceed official ones and vary considerably across countries from 29.4% in Gabon to 78.1% in Kenya. Within countries, delineated areas show great size diversity following Zipf's law, without much urban primacy. Cities’ land area increases slightly less proportionally to their population. Monocentric population patterns with declining population density toward peripheries largely dominate, though some large multicentric extended, not necessarily capital, cities exist. • Urban areas, cores, cities and centers, towns delineated for 47 SSA countries • Country-specific dartboard approach to measure spatial concentration • Urbanisation rates above official ones, Zipf’s law, little urban primacy • Most cities monocentric with negative within-city population gradients • A few extended cities, not always capitals, with many population sub-centers