Cities across sub-Saharan Africa are growing faster than their official maps. In Dar es Salaam, much of what we know about the built environment came not from government records but from community mapping. Between 2015 and 2020, the Ramani Huria project trained students and residents to map buildings, roads, drains and flood-prone wards across roughly three-quarters of the city, and released the data openly through OpenStreetMap. Less settled is what happens to that data after the project closes and the funding ends.

We will look into the Climate Risk Database (CRD), built to continue Ramani Huria's work. It is an open-source GeoNode platform developed by the Resilience Academy, a partnership between Tanzanian universities and the University of Turku hosted at Ardhi University, and it gives community-generated geospatial data a managed home for climate risk work. We studied the CRD as a socio-technical system: its technology, its data, its community, and the training that feeds it. The platform now holds 429 open resources used by 712 registered users, with metadata completeness averaging 93.7%, kept up by volunteer curation rather than a paid team. Its strengths and gaps mirror how the data is made. Exposure data, the buildings and settlements that communities map well, make up 43.6% of the database, while hazard data sit at 13.2%. A training programme that reached 1,715 people and placed 775 student interns between 2019 and 2022 grew skills and data at once, and new contributions slowed when it ended.
The case shows that open tools and an active mapping community can sustain a real data service in a data-scarce city, provided an institution keeps it running after the donors leave.