Infrastructure deficits and informal settlements in sub-Saharan Africa.

Sustainable development is an imperative worldwide but metrics and data on poverty and quality of life have remained too coarse and abstract to characterize challenges adequately and guide practical progress. Nowhere is this challenge greater than in Africa, where we still know little about the spatial details of development. Here we leverage a comprehensive, high-precision dataset of building footprints to identify infrastructure deficits and infer informal settlements down to the street block level everywhere in sub-Saharan Africa. We identify a general pattern of informality with cities showing, on average, greater access to infrastructure and services than rural and peri-urban areas. We show that such patterns of informality are characterized by consistent statistical distributions reflecting uneven local development. We also show that these physical measures of informality are systematically associated with many indicators of human deprivation, which form a single principal component co-varying predictably with specific changes in street access to buildings. These results demonstrate that the localization of sustainable development is possible down to the street level at a continental scale and provide a general distributed strategy for accelerating progress in infrastructure and service expansion that taps local innovations in systematic, equitable and context-appropriate ways.