On Wednesday, November 14, we joined more than 170 volunteers at the World Bank’s Washington, D.C. headquarters to draw little red boxes on a map of Alajo—a small town in the coastal metropolis of Accra, Ghana.
Some might find tracing a map of a city 8,500 kilometers away to be a surprising way to spend an afternoon, but there are good reasons for it. The boxes represented buildings, and they will go on to become invaluable geospatial data that will help the residents of Accra prepare for and respond to flood risk. Home to over two million people, Ghana’s capital city is highly vulnerable to flooding. In 2015, torrential rainfall left much of the city underwater—affecting 53,000 people and causing an estimated US$100 million in damages.
In just a little over two hours, the volunteers made over 3,000 edits to the map of Alajo, complementing the work of local teams in Ghana that are leading data collection efforts in the field. Once validated by more experienced mappers, the data collected will help guide improvements to Accra’s solid waste disposal management system, and also inform the upgrading of settlements vulnerable to flooding.