How the cloud images are created...

The cloud images are provided by the NERC Satellite Receiving Station, Dundee University, Scotland. They provide five images which together cover the globe. In their raw form, these images are of course half-hemispheres and thus, circles.

The images are assembled into a single flat map by the open-source, volunteer xplanet project run by CalTech graduate Hari Nair and distributed to a number of mirror sites.

The composite image can then be accessed by programs like EarthDesk for free. EarthDesk selects a random mirror each time it needs to update the clouds.

Many other applications use the same list of mirrors. The goal is to distribute network traffic to help reduce bandwidth on individual servers. It also reduces the burden on the Dundee UK Satellite Station as only one site is pulling back the images every three hours. By keeping bandwidth to a minimum, it is hoped that this free data service can continue indefinitely.

Corrupt images...

Sometimes, for a number of reasons, a corrupt cloud image can be generated, it almost always corrects itself on the next update, three hours later.

Many thanks to Mr. Hari Nair for offering and supporting this service!

Trygve Inda
President
Xeric Design, Ltd.