The United States Geological Survey created TerraLook to make satellite imaging easier for people outside the remote sensing community. Using the raw data generated by LandSat and other remote sensing satellites requires training and expensive software. For most people - journalists, students, and other amateurs - a picture is all they need to illustrate a story, document conditions, or explain how things change over time. TerraLook makes it easier for them to use the forty year record of LandSat images.
TerraLook takes the visible and infrared data collected by the LandSat and Aster satellites and converts them into simulated natural-color JPEG files. The satellites cameras don’t work the same way as the camera in your phone. The satellites measure light in narrow bands around wavelengths that mean something to scientists, but don’t match the way we see visible light. The health of trees and other plants, for example, affects the way they reflect infrared light. The TerraLook images map the satellite data to the red, green, and blue channels that photo-editing software understands. TerraLook also geo-references the JPEG files which lets you use them in mapping software.
You can create your own collection of TerraLook images by using USGS’ Glovis web visualization tool or download preselected collections from Nasa’s Jet Propulsion Laboratory. The Windows-based TerraLook desktop software - available through the sourceforge open source service - gives you some simple image-editing and geographical information systems tools. For example, you can use the TerraLook software to measure distances and annotate images. The sourceforge documentation and USGS tutorials will help you get started.