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The Lost continent of

You've found a bug on my site!

The central enemy of reliability is complexity.

Geer et al.

My Desktop Wallpaper

Live Images from Space...

Wallpaper on a desktop?
My Wallpaper is a photo of earth, overlaid with real, uptodate satelite cloud data, and two other astronomical bodies, as they would currently look from earth. It presents me with a constantly changing, 'live' view of the Universe, without having to leave the office (who would want to?).

It is produced by three shell scripts, the remarkable XPlanet package, and a number of image files.

Starting images - Earth

Fig. 1. True colour composite images of earth, dayside, and nightside.

Beginnings

We start with a couple of flat images of earth, courtesy of 'The Living Earth® Inc.' The Living Earth image is a highly accurate composite of multiple high-resolution satellite images to remove clouds, in the colours. There are two images, one daylit image, and another of earth at night time.

We will use these images as the basis for our earth image. The XPlanet program will 'wrap' the flat image around a sphere, and output an image file.



Fig. 2. Raw cloud Data, cleaned and processed cloud image, and a earthdayside/cloud composite, respectively.

Clouds

The globe produced from these two images is very pretty - it has the bright blues and greens of the dayside, and the city lights gleaming on the night side - but it could be made prettier, and more interesting, by the addition of clouds.

The Author of XPlanet publishes a new cloud map of the earth (middle image) every 3 hours using live GOES, METEOSAT, and GMS geostationary satellite imagery, such as the image with the ugly pink lines to your left. To add clouds to our globe we first download the cloud images, then add the clouds seperately to the day and night time earth photos (bottom image is the day image plus clouds).

This process is looked after by the script file clouds.sh, which should be run every 3 hours to match the update frequency. I thus get 8 cloud updates a day, so that I can watch the progress storms and fronts as they happen!



Fig. 3. Flat image of Mars, a generated globe of Mars, and a generated globe of the waxing moon.

The Moon and Planets

Having an automatically updating, realistic earth floating around on your desktop is very cool, but wouldn't it be even better if you could see what the other planets and the moon were up to? The script moon_and_planets.sh generates images of these astronomical bodies as they would look from an earthly vantage point. It only needs to be run every day or two.



Putting it all Together

So far we have gone through a couple of scripts, and have produced a number of images:

  1. A large format image of earth by daylight, with recent satelite cloud date superimposed upon it.
  2. The same cloud data laid upon a large format image of earth by night.
  3. An image of the moon, as currently seen from earth.
  4. An image of each of the eight remaining planets, as they would currently look from earth.