In order to ensure a close match between different national coverages, and to obtain maximum compatibility with other standard medium resolution data sets, all national boundaries and coastlines were replaced with the political boundaries template (PONET) of the Digital Chart of the World (DCW). The DCW is a set of basic digital GIS data layers with a nominal scale of 1:1 million scale. In order to maximize comparability across national boundaries, all district-level population figures were projected to 1995.