Imagine everyone in Glasgow, Turin or Lyons being forced out of their homes. This is the scale of the crisis in the Darfur region of Sudan in North Africa.
About one and a half million people have been driven from their villages across an area the size of France. With such a huge area to cover, images from space are a vital aid to workers on the ground.

An ESA-supported group called Respond is using these images to produce up-to-date maps of the scattered camps and surrounding landscape.
In less than 12 hours, these are sent directly to workers from organisations such as the Red Cross, the United Nations and the German federal disaster relief agency.
The Respond team makes use of 10 different sensors from 9 spacecraft. These include a radar instrument and a camera system on ESA’s Envisat.

Envisat’s radar, which can see through clouds, day or night, was especially valuable during Sudan’s summer rainy season.
Alongside pictures from satellites such as SPOT-5, the radar data showed flooded areas and roads that were still passable.
Meanwhile, UK-built Disaster Monitoring Constellation satellites are mapping local vegetation. This is important because the people of Darfur rely on firewood for cooking.