Africa's drone mapping experts

Only a small percentage of the African continent is mapped in any detail.

This has huge consequences for disaster relief and also for urban planning, as people pour into cities at an unprecedented rate.

In Zanzibar, East Africa, the World Bank is funding a new mapping initiative which is becoming a model for how other parts of the continent could keep on top of the rapidly changing landscape.

Katie Prescott has been to take a look.

Filmed by Chris Morgan