posted on Apr, 7 2005 @ 07:13 PM
Yes, there are alfalfa crops in the Mojave desert. More green coming in from tax breaks than alfalfa production.
Satellites take infrared images in many narrow bands of the IR spectrum. By taking multispectral scans, they can measure fine gradations in
temperature range in a building. They can see blighted crops in a field of healthy crops. And they can acquire data through cloud cover.
The colors are put in by a computer. Do a Google image search for Landsat. Some images appear in true colors, but that's just for pretty, a PR thing.
Some are in strange unnatural color combinations. The computer image manipulators emphasized colors depicting what the analysts need to see - industry
in yellow, suburbs in pink - creating a false color image.
These circles are colored partly to identify them, to clarify what you are seeing, so people who drove past these things on the freeway go "Oh -
When they ( terraserver ) want to obscure things on the ground, they substitute aerial images from the 50's, or show you pictures of ceiling tiles.