Chad

The International Charter "Space and Major Disaster" was activated twice last week for floods in Africa: Chad and Nigeria.

UNITAR/UNOSAT on behalf of UNICEF activated the mechanism for Chad on 10 October 2012. Heavy rains which started in early August had caused continuing floods in Chad. Hundreds of thousands of people have been affected by the floods, with damage to both property and agriculture. In the Rig Rig District of the Kanem Region, 220 houses were destroyed and 3000 people were displaced. In the Sila Region, more than 13,000 houses were affected and the flood waters blocked major humanitarian supplies. In Guera, an estimated 850 people were in need of emergency support. And floods have also been reported in the capital, N'Djamena. In September the flood waters were still present, and had affected an estimated 466,000 people, and killed 34. 96,000 houses were reported destroyed and 255,000 hectares of crops lost.

In Nigeria, the Nigerian National...

For the first time, the population of an entire city has been estimated from space through a pioneering project to speed up medical and disaster relief efforts. By analysing satellite images of disaster zones and famine, war or disease-hit areas where census data is unreliable, or cities unreachable, researchers hope to make rapid and more accurate estimates of how many people might need help.

"Population numbers are crucial to everything we do," says Ruby Siddiqui of the global charity, Medicins Sans Frontières, a collaborator in the project to evaluate the satellite counting technique. "We need to plan the size, scale and mode of interventions, and without population numbers we can't do this," she says.

At present, groups like MSF rely on the "quadrat" method to estimate population size. Surveyors visit a sample of individual households to find out how many people live in each type of dwelling. From this, they estimate the...