Abstract: The Landsat Thematic Mapper (TM) is a sensor carried 
                onboard Landsats 4 and 5 and has acquired images of the Earth nearly 
                continuously from July 1982 to the present, with a 16-day repeat cycle.
                Landsat TM image data consist of seven spectral bands (band designations) with a 
                spatial resolution of 30 meters for bands 1 to 5 and band 7. Spatial resolution for 
                band 6 (thermal infrared) is 120 meters, but band 6 data are oversampled to 30 
                meter pixel size. Approximate scene size is 170 km north-south by 183 km 
                east-west (106 mi by 114 mi). 
                Systematic Correction (Level 1G) includes both radiometric and geometric correction. 
                The scene will be rotated, aligned, and georeferenced to a user-specified map 
                projection. Absolute geometric accuracy of the systematically corrected Landsat 
                TM product can vary, depending on the accuracy of the predicted ephemeris that 
                is used for processing. Please be aware that TM Level 1G products may require 
                additional image geometric correction and/or co-registration to known ground 
                control points (GCPs). 
                Precision Correction (Level 1P) includes radiometric and geometric correction, as 
                well as the use of ground control points (GCPs) to improve geometric accuracy. For 
                locations outside the United States, accuracy of the precision-corrected product will 
                depend on the availability of local GCPs. 
                Terrain Correction (Level 1T) includes radiometric and geometric precision 
                correction, as well as the use of a digital elevation model (DEM) to improve the 
                satellite model and to correct for relief displacement caused by local terrain. For 
                locations outside the United States, the accuracy of a terrain-corrected product will 
                depend on the availability of local ground control points (GCPs), as well as the 
                quality of the best available DEM.