By Nick

A SPOT4 satellite image of flooding in Barangay, Manilla, The Philippines in December 2011. Image from the


Normally this kind of imagery is something I’d reserve for a Not So Serious Sunday, but these satellite images aren’t just for looking pretty, they help save lives. I’ll admit I didn’t know about the Disaster Charter before listening to this slideshow. But what a great asset it is to the world. Helping to save lives by providing immediate imagery of disaster areas.

BBC News – Saving lives from space.

Typically polar orbiting satellites that produce these kind of false-color images take 16 days to image the entire globe. In times of disaster you need up to the date information. The more information you have, the more lives you can save. Since we have around 3000 satellites in space, some of which are in the required orbits and have the required technology to take these kind of images, the ability to commandeer any available satellite for immediate photography of the disaster area is a fantastic idea and a great sign of universal co-operation.

The images look a bit weird because they are known as false colour images. Pictures are taken in multiple wavelengths of light. Not just visible light, but also different spectra of infra-red and ultra-violet.  Some of the infra-red spectra are especially good at imaging trees and plants, even more so than green! So to put all these wavelengths into a simple image, they take three wavelengths and assign one to red, one to green and one to blue, in a way that creates good contrast, and makes the things that need to be seen visible.