Existing spatial population datasets for Africa are currently built upon low resolution census data that are often over 10-20 years old, and incomplete ancillary road and settlement datasets. The AfriPop project produces detailed and freely available population distribution maps for the whole of Africa, overcoming some these drawbacks by drawing on more detailed and contemporary census and settlement databases than have ever before been assembled.
Accurate population mapping requires detailed, contemporary census data, irrespective of modelling approach. AfriPop has therefore made the construction of a unique GIS-linked database of census and official population estimate data a priority, targeting the most recent and spatially detailed datasets available. The vast majority of people across Africa reside in settlements of varying sizes, therefore, the accurate mapping of settlements (from large cities to small villages) is important for identifying where populations reside within census units. AfriPop utilises satellite imagery for mapping settlements, specifically, 30m spatial resolution Landsat Enhanced Thematic Mapper (ETM) satellite imagery. Through detailed mapping of settlements, and linkage of these settlement extents with gazetteer population numbers, the substantial majority of African residents can be mapped within settlements with good precision. Mapping of the remaining minority rural populations uses settlement maps to refine land cover data, while local high resolution census data from across the continent is used to identify typical regional per-land cover class population densities, which are then applied to redistribute rural census counts to map human population distributions.