The solution
BBC News reported in February 2016 on SnooCode, an app founded by Sesinam Dagadu, who set it up in 2011 and returned to Ghana in 2013 to work on it full-time. In Ghana, directions use landmarks like 'beside the mango tree' or 'after the blue kiosk'. Dagadu got the idea working for a bank in Accra, where field staff opening accounts kept getting lost.
The app generates a unique code for every property, pinpointing it with GPS: you stand at your house, push the code button, and get a code like a UK postcode but far more precise. You then enter the code into the app's mapping service for the best route. It is free and works without an internet connection, and only needs the alphabet and numbers, not words. Residents without smartphones, like his grandmother, keep the code, for example stuck on the fridge.
Ghana's emergency services signed up: all 14 ambulance stations in Accra had installed it, Kumasi's were next, and 160 emergency workers were trained. A senior EMT said dispatchers otherwise phone callers again when a landmark has vanished.
Why it worked
GPS gives a precise fix even where streets and signs are absent.
A short code needs no reading of whole words, so more people can use it.
Offline operation suits patchy connectivity.
Emergency services have a direct, measurable need for exact locations.
What can be applied
When the physical address system is missing, a code anchored to GPS can replace it without requiring literacy or smartphones for everyone.
Aftermath
According to the BBC, average ambulance response in Ghana was 19 minutes in 2014 against a recommended 8. The National Ambulance Service's head of operations said that if the public knew about the system it could cut response time by 50%, although road conditions and traffic remain challenges. Dagadu also saw uses for land marking, refuse collection and public health.
FOLLOW THE EVIDENCE