Tri-Decadal Global Landsat Orthorectified TM Scene V1

The average acquisition date for the Tri-Decadal Global Landsat Orthorectified TM data is 1990 (+/- 3 years). However, individual scenes range from 1985 to 1996. These Landsat data have been orthorectified, using geodetic and elevation control data to correct for positional accuracy and relief displacement. Large blocks of Landsat data were adjusted through a patented procedure using pixel correlation to acquire tie-points within the overlap area between adjacent Landsat images.

The Tri-Decadal Global Landsat Orthorectified data collection consists of a global set of high-quality, relatively cloud-free orthorectified MSS, TM and ETM+ imagery from Landsats 1-5 and 7. This dataset was selected and generated through NASA's Commercial Remote Sensing Program, as part of a cooperative effort between NASA and the commercial remote sensing community to provide users with access to quality-screened, high-resolution satellite images with global coverage over the Earth's land masses. The data collection was compiled via NASA contract with Earth Satellite Corporation (Rockville, MD) in association with NASA's Scientific Data Purchase program.

The Tri-Decadal Global Landsat Orthorectified data collection consists of approximately 7,500 MSS (Landsat 1-5) images, 7,461 TM (Landsat 4-5) images and approximately 8,500 ETM+ (Landsat 7) images, which were selected to provide three full sets of global coverage over an approximate 25-year interval (circa 1975, circa 1990 and circa 2000). All selected images were either cloud-free or contained minimal cloud cover. In addition, only images with a high quality ranking in regards to the possible presence of errors such as missing scans or saturated bands were selected.