Landsat TM Graphic
Flagstaff Atlas
Landsat Thematic Mapper Images
Click on thumbnail images to view larger image. Images are approximately 800 x 800, and may be in excess of 500 kb.
The Landsat TM imaging system, launched in 1982 by the United States, collects six reflective spectral bands (blue, green, red, near infrared, and two mid infrared), having a spatial resolution of 30 meters, and a thermal band having 120 meter spatial resolution. The area covered by a single image is approximately 185 by 185 km (115 by 115 miles); the satellite orbits at an altitude of about 700 km (438 miles). Landsat TM images collected on June 22, 1991, and on January 15, 1983, were used for this project; the June image had a near maximum sun elevation angle, whereas the January image had a near minimum angle. A low sun elevation angle is better at enhancing structural features, even though in this case, there was some snow cover in the area. These data were corrected to remove geometric distortions and radiometric noise. Absolute radiometric calibration and corrections were not needed because the application is aimed at extracting high frequency information (that is, linear/structural features). The digital data were processed using spatial filters to enhance the structural information at several different frequencies, including both edge and textural enhancements. These types of digital image processing procedures generate image products useful in helping identify both areas that contain individual lineaments and areas with a high density of surface fractures (both important in surface to ground water relations).



Back to the Flagstaff Atlas Title Page

TerraWeb Home

U.S. Department of the Interior | U.S. Geological Survey | Jobs
Home | Search | Disclaimers & Privacy Web Rings
Send comments to webman@TerraWeb.wr.usgs.gov
URL:
Last Modified: Thu Oct 31 15:19:35 MST 2002
FirstGov: Your First Click to the U.S. Gov ernment