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.