Each country page starts from the most reliable published reference for that country’s major inter-city routes — for Nigeria, that’s the UNDP-sourced road distance matrix between all 37 state capitals. Any route not in that reference is estimated from GPS coordinates using a road-distance correction factor calibrated against the verified data itself, and always clearly labelled as an estimate rather than presented as exact.
Each page starts from the most reliable published reference for major routes, then estimates remaining routes from GPS coordinates with a calibrated correction factor. Verified and estimated figures are always labelled separately.
Each country page needs a real town list, coordinates, and a verified distance reference researched directly — that takes time to do properly. More countries are added as that research is completed.
Reviewed by Evelyn John, Auto Sales Expert.