USGS EROS Archive - Landsat Archives - Landsat 7 Enhanced Thematic Mapper Plus (ETM+) Level-1 Data Products
Science Center Objects
Enhanced Thematic Mapper Plus (ETM+) 15- to 30-meter multispectral data from Landsat 7. (1999 to present)
The Landsat Enhanced Thematic Mapper Plus (ETM+) sensor onboard the Landsat 7 satellite has acquired images of the Earth nearly continuously since July 1999, with a 16-day repeat cycle. Landsat 7 images are referenced to the Worldwide Reference System-2.
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: Using Landsat 7 Data.
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).
Standard Processing Parameters
All Landsat 7 ETM+ products are processed through the Level 1 Product Generation System (LPGS) with the following parameters applied for Product Type and L1T Terrain Correction*.
|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||HTTPS 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 (GloVis).
Landsat 7 ETM+ Collection 1
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)
- Tier 1 (T1) – Contains the highest quality Level-1 Precision Terrain (L1TP) data considered suitable for time-series analysis. The georegistration is consistent and within prescribed tolerances [<12m root mean square error (RMSE)].
- Tier 2 (T2) – Contains L1TP scenes not meeting Tier 1 criteria and all Systematic Terrain (L1GT) and Systematic (L1GS) scenes. Users interested in Tier 2 scenes can evaluate the L1TP RMSE and other properties to determine suitability for use in their applications and studies.
- Real-Time (RT) – Contains newly acquired Landsat 7 scenes, which require a period of evaluation and calibration adjustment after acquisition but are processed immediately based on preliminary calibration coefficients, assigned to the temporary RT Tier, and made available for download. When definitive calibration information becomes available, these scenes are reprocessed, assigned to the appropriate Tier 1 or Tier 2 category, and removed from the RT Tier (Temporary designation).
The Landsat Collections web page contains additional information about changes applied to Landsat Level-1 data products for Collection 1.
Coverage Maps indicating the availability of Landsat 7 ETM+ Collection 1 products are available for download.
- USGS Landsat - Earth Observation Satellites Fact Sheet
- Landsat Homepage
- Landsat FAQs
- Landsat 7 Science Data Users Handbook
- Technical Information (Including calibration and definitive ephemeris files)
- Project Documentation
- Landsat Collections
- Landsat 7 ETM+ Digital Object Identifier (DOI) number: /10.5066/F7WH2P8G
Landsat 7 scenes held in the USGS archive can be searched using EarthExplorer, the USGS Global Visualization Viewer (GloVis), or the LandsatLook Viewer. On EarthExplorer, Landsat 7 scenes can be found under the Landsat menu in the “Landsat Collection 1 Level-1” section, in the “Landsat 7 ETM+ C1 Level-1” dataset.
Newly acquired Landsat 7 scenes become available for search and download within 24 hours after data acquisition. To view real-time acquisitions of Landsat 7, 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 format.