LandSAT

Landsat satellites have taken specialized digital photographs of Earth’s continents
and surrounding coastal regions for over three decades, enabling people to study
many aspects of our planet and to evaluate the dynamic changes caused by both natural
processes and human practices
HISTORY
In 1975, NASA Administrator Dr. James Fletcher predicted that if one space age development
would save the world, it would be Landsat and its successor satellites. Since the
early 1970s, Landsat has continuously and consistently archived images of Earth;
this unparalleled data archive gives scientist the ability to assess changes in
Earth’s landscape.
For 34 years, the Landsat program has collected spectral information from Earth’s
surface, creating a historical archive unmatched in quality, detail, coverage, and
length.
“It was the granddaddy of them all, as far as starting the trend of repetitive,
calibrated observations of the Earth at a spatial resolution where one can detect
man’s interaction with the environment,” Dr. Darrel Williams, the Landsat 7 Project
Scientist, states about Landsat.
Landsat sensors have a moderate spatial-resolution. You cannot see individual houses
on a Landsat image, but you can see large man-made objects such as highways. This
is an important spatial resolution because it is coarse enough for global coverage,
yet detailed enough to characterize human-scale processes such as urban growth.