Long Term Archive
Landsat ETM+ Image (Seattle, WA)
All Landsat 7 scenes collected since May 30, 2003 have data gaps due to the Scan Line Corrector (SLC) failure. Landsat 7 scenes acquired after this date are categorized as SLC-off. This page describes the details of the SLC-off data, and provides established methods to fill the scenes: http://landsat.usgs.gov/using_Landsat_7_data.php.
Landsat 7 ETM+ images consist of eight spectral bands with a spatial resolution of 30 meters for bands 1 to 7. The panchromatic band 8 has a resolution of 15 meters. All bands can collect one of two gain settings (high or low) for increased radiometric sensitivity and dynamic range, while Band 6 collects both high and low gain for all scenes. Approximate scene size is 170 km north-south by 183 km east-west (106 mi by 114 mi).
All Landsat 7 ETM+ products are processed through the Level 1 Product Generation System (LPGS) with the following parameters applied.
|Product Type||L1T Terrain Corrected*|
|Resampling Method||Cubic Convolution (CC)|
|Map Projection||UTM – WGS 84
Polar Stereographic for the continent of Antarctica.
|Image Orientation||Map (North Up)|
|Distribution||FTP Download Only|
|Delivery Time||Within 24 hours of new acquisitions; 1 to 3 days for processing requests for already-archived data|
* While most Landsat scenes are processed with the Standard Terrain Correction (Level 1T), some scenes do not have the ground-control or elevation data necessary to perform these corrections. In these cases, the best level of correction is applied. (See Landsat Processing Details for details on correction levels.)
Specific Level 1T scenes are available for most of the globe under the Global Land Surveys (GLS) collections of 1975, 1990, 2000, 2005, and 2010. These datasets can be found on EarthExplorer or the USGS Global Visualization Viewer.
Landsat Tiers are the inventory structure for Landsat Collection 1 Level-1 data products and are based on data quality and level of processing. All scenes in the Landsat archive are assigned to a Collection category. The purpose of Collection categories is to support rapid and easy identification of suitable scenes for time-series pixel level analysis. During Collection 1 reprocessing, all Landsat 7 ETM+ scenes in the USGS archive are assigned to a specific “Tier”. These data have well-characterized radiometric quality and are cross-calibrated among the different Landsat sensors.
Collection Category (Tier)
The Landsat Collections web page contains additional information about changes applied to Landsat Level-1 data products for Collection 1.
Landsat 7 scenes held in the USGS archive can be searched using EarthExplorer, the USGS Global Visualization Viewer (GloVis), or the LandsatLook Viewer. (Only scenes with browse capability can be searched and downloaded from GloVis.)
Newly acquired Landsat 7 scenes become available for search and download within 6 to 24 hours. To view real-time acquisitions of Landsat over North America, please visit EarthNow!
Data is delivered from the USGS only in digital format, with the parameters noted above. There are several commercial firms that may provide data in different formats, or printed images from USGS digital data.
Collection 1 Landsat 7 ETM+ scenes are available in EarthExplorer. The Collection 1 data are located under the Landsat Archive/Collection 1 Level-1 menu as “L7 ETM+ C1 Level-1”. The data will also remain under the Landsat Archive/Pre-Collection menu as “L7 ETM+ SLC-off (2003-present)” and “L7 ETM+ SLC-on (1999-2003)” for 6 months after the transition to the tiered structure.
For information on how to cite USGS data plus guidance on usage restrictions,
please see our Data Citations and Use page at https://lta.cr.usgs.gov/citation.
Any use of trade, firm, or product names is for descriptive purposes only and
does not imply endorsement by the U.S. Government.
Long Term Archive User Services
U.S. Geological Survey (USGS)
Earth Resources Observation and Science (EROS) Center
47914 252nd Street
Sioux Falls, SD 57198-0001
Phone Number: 605-594-6151
Toll Free: 800-252-4547
Business Hours: Monday thru Friday, 8:00 a.m. to 4:00 p.m., Central Time