Satellite imaging used to be only available to the
military of the
superpowers countries. However, now many
commercial satellite imaging companies offer to acquire
images of any square meter of the
earth, for a fee. Or the provide access to their
catalogues and
archive of already
acquired images, which can be bought for less fee.
Used to be only objects much bigger than 20m can be discerned from this commercial satellites, now even objects as small a 1m can be imaged.
Some sources of satellite images:
- Space Imaging (www.spaceimaging.com) - LandSat and Ikonos images.
- Spot Inc (www.spot.com) - Spot images