A few days ago, a beautiful satellite photo of snow-covered Great Britain got quite a lot of press coverage (and garnered me a couple of hundred retweets). The image was taken with the snappily-named MODIS camera which flies aboard two NASA Earth Observation System satellites: Terra and Aqua.
Turns out these are pretty neat pieces of kit - they actually record images in 36 frequency bands ranging from blue to thermal infra-red. The two satellites are in a sun-synchronous polar orbit which means they each record an image of the whole earth every day: Terra in the morning and Aqua in the afternoon.
All the image data is collated and released into the public domain by NASA on several sites, but the most interesting outlet for the data is the semi-realtime site here.
It struck me that it would be pretty cool to have the most recent image on your desktop, updated twice a day. So I wrote a slightly hacky little script to do it. NASA provide georectified true-colour images for a selection of regions, including most of Great Britain, so I’m just co-opting that. It does mean I don’t have a full image of GB, but my screens aren’t really the right aspect ratio for that anyway.
Here’s an example of the image it produces (for my dual 19" monitor setup at home).
I’ve just learned that the MODIS satellites constantly downlink their imagery in the clear, so I think the next step is to build a receiver and grab the data directly ;).