USGS EROS Archive - Landsat Legacy - Tri-Decadal Global Landsat Orthorectified TM and ETM+ Pan-sharpened Mosaics
Science Center Objects
The Tri-Decadal Global Landsat TM Orthorectified and ETM+ Pan-sharpened Mosaics data collections are derived from a global set of high-quality, relatively cloud-free orthorectified TM and ETM+ imagery from Landsats 4, 5 and 7.
The Tri-Decadal Global Landsat TM Orthorectified and ETM+ Pan-sharpened Mosaics data collections are derived from a global set of high-quality, relatively cloud-free orthorectified TM and ETM+ imagery from Landsats 4, 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 make available 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, now MDA Federal Inc. (MDA), (Rockville, MD) in association with NASA's Scientific Data Purchase program.
The collections are derived from approximately 7,461 TM (Landsat 4-5) images and approximately 8,500 ETM+ (Landsat 7) images, which were selected to provide a full set of global coverage (circa 1990 and circa 2000). All selected images are either cloud-free or contain minimal cloud cover. Only images with a high quality ranking (based on the possible presence of errors such as missing scans or saturated bands) were selected.
Tri-Decadal Global Landsat Orthorectified TM Mosaic The average acquisition date for the Tri-Decadal Global Landsat Orthorectified TM data is 1990 (+/- 3 years). However, individual scenes may 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 Landsat TM scenes were mosaicked by matching individual histograms and feathering overlapping areas together to create a TM Mosaic product. The mosaics are contrast enhanced color image data products comprised of Landsat TM bands 7, 4, 2 composited in red, green, and blue, respectively. The resulting mosaics are made up of several Landsat scenes covering a 5-degree (north-south) segment of a standard, 6-degrees (east-west), UTM partition. Tri-Decadal Global Landsat Orthorectified ETM+ Pan-sharpened Mosaic These data products consist of pan-sharpened versions of the ETM+ scenes. The pan-sharpening process involved a resolution merging process, which allows the fusion of the higher-resolution panchromatic band (8) with selected lower-resolution multispectral bands (7,4,2) to create a higher-resolution ("pan-sharpened") color image.
All Tri-Decadal Global Landsat Orthorectified data products have been pre-processed according to a standardized set of processing parameters.
|TM Mosaics||ETM+ Pan-sharpened Mosaics|
|Level of processing||Terrain corrected||Terrain corrected|
|Number of bands
|3 (bands 7,4,2)||3 (bands 7,4,2)|
|Projection||Universal Transverse Mercator (UTM)||Universal Transverse Mercator (UTM)|
|Resampling||Nearest Neighbor||Cubic Convolution|
Coverage Maps indicating the availability of TM Mosaics products are available for download.
Coverage Maps indicating the availability of ETM+ Pan-Sharpened Mosaics products are available for download.
Tri-Decadal Global Landsat Orthorectified TM and ETM+ Pan-sharpened Mosaic data are currently available from the USGS EROS archive and may be searched and downloaded online through EarthExplorer. The collection are located under the Landsat Legacy category.
Note: The full Tri-Decadal Global Landsat Orthorectified TM and ETM+ Pan-sharpened Mosaic data collection consists of approximately 608 TM (Landsat 4-5) mosaics and approximately 3,100 ETM+ (Landsat 7) mosaics. However, not all of these images are currently available for search and order from USGS EROS at this time. Users will need to run a search to determine the scene availability for any given location.