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Product Description
The Enhanced Thematic Mapper Plus (ETM+) is a multispectral scanning radiometer that is carried on board the Landsat 7 satellite. The sensor has provided nearly continuous acquisitions since July 1999, with a 16-day repeat cycle. An instrument malfunction occurred on May 31, 2003, with the result that all Landsat 7 scenes acquired since July 14, 2003 have been collected in "SLC-off" mode (Details).
The ETM+ instrument provides image data from eight spectral bands (band designations). The spatial resolution is 30 meters for the visible and near-infrared (bands 1-5 and 7). Resolution for the panchromatic (band 8) is 15 meters, and the thermal infrared (band 6) is 60 meters. The approximate scene size is 170 x 183 kilometers (106 x 115 miles).
For all Landsat 7 ETM+ data (including SLC-off products), the following levels of correction are available to the general public (detailed comparison):
- Raw Uncorrected (Level 0Rp) has no radiometric or geometric correction applied. Scan lines are reversed and nominally aligned. Image data is provided in 8-bit (DN) values.
- Systematic Correction (Level 1G) includes both radiometric and geometric correction. Image data is provided in rescaled 8-bit (DN) values. The scene will be rotated, aligned, and georeferenced to a user-defined map projection. Geometric accuracy of the systematically corrected product should be within 250 meters (1 sigma) for low-relief areas at sea level. Level 1G products can be processed by either the Level 1 Product Generation System (LPGS) or the National Land Archive Production System (NLAPS).
- Systematic Correction (Level 1G) Gap-filled (SLC-off only) includes radiometric correction, geometric correction, and replacement of all missing image pixels within the SLC-off ("primary") scene with estimated values based on histogram-matched data from a user-defined SLC-on ("fill") scene. The image will be rotated and aligned to a user-specified projection. A scan gap mask is included with the final product. All Level 1G SLC-off gap-filled products are processed by the Level 1 Product Generation System (LPGS). (Detailed Description)
For all Landsat 7 ETM+ data (including SLC-off products), the following levels of correction are available to approved USGS researchers only:
- Precision Correction (Level 1P) includes radiometric and geometric correction, as well as the use of ground control points (GCPs) to improve accuracy. For locations outside the U.S., accuracy of the precision-corrected product will depend upon the availability of local GCPs. All Level 1P products are processed by the National Land Archive Production System (NLAPS).
- Terrain Correction (Level 1T) includes radiometric, geometric, and precision correction, as well as the use of a digital elevation model (DEM) to correct parallax error due to local topographic relief. For locations outside the U.S., the accuracy of the terrain-corrected product will depend upon the availability of local ground control points (GCPs), as well as the resolution of the best available DEM. All Level 1T products are processed by the National Land Archive Production System (NLAPS).
Raw uncorrected (Level 0Rp) data will have no projection or datum applied. Level 0Rp data are provided in HDF format and distributed on CD-ROM, DVD, or via File Transfer Protocol (FTP).
For all Level 1 products (Level 1G/1P/1T), the available processing options, format, and media will depend on the processing system that is used to generate the product:
| Ordering Parameters |
Options (NLAPS) |
Options (LPGS) |
| Map projection |
UTM
SOM-B
other*
|
UTM
SOM-B
LCC
PS
PC
TM
OMA
OMB
|
| Horizontal datum |
WGS84
NAD83
NAD27
other* |
WGS84 |
| Resampling method |
CC (Cubic Convolution)
NN (Nearest Neighbor)
other* |
CC (Cubic Convolution)
NN (Nearest Neighbor)
MTF (Modulation Transfer Function) |
Scan gap interpolation
(SLC-off only) |
default only (2 pixels) |
0 to 15 pixels (default = 2 pixels)
more information |
Scan gap interpolation
(SLC-off Gapfilled only) |
n/a |
default only (0 pixels) |
| Image Orientation |
Map (north up)
Path (satellite/nominal)
other* |
Map (north up)
Path (satellite/nominal) |
| Pixel size |
30 meter (30m/15m/60m)
28.5 meter (28.5m/14.25m/57m)
25 meter (25m/12.5m/50m)
other*
|
30 meter (30m/15m/60m)
28.5 meter (28.5m/14.25m/57m)
25 meter (25m/25m/50m)
other*
|
| Multi-scene** |
available for up to 3 scenes
(CD limit = 2 scenes) |
currently not available |
| Scene shift |
available in 10% increments
(along-path shift only)
|
currently not available |
| Format |
GeoTIFF
NDF (NLAPS Data Format)
Fast L7 |
GeoTIFF
HDF (Heirarchical Data Format, v4.1)
Fast L7 |
| Media |
CD-ROM
DVD
FTP |
CD-ROM
FTP |
*Other options may be available upon request.
**Multi-scenes are only available for scenes (rows) that were acquired and archived
consecutively along the same path for the same date.
Additional Information:
Landsat 7 Homepage
Landsat 7 FAQs
Landsat 7 Science Data Users Handbook
Landsat 7 Documentation (including Data Format Control Books)
Technical Information (CPFs, definitive ephemeris, data acquisition)
Landsat 7 SLC-off Data Products
SLC-off Usability Report
ETM+ Abstract
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NLAPS vs. LPGS Processing
There are two separate processing systems used to generate USGS Landsat 7 ETM+ Level 1 products:
- Level 1 Product Generation System (LPGS) - Level 1R and Level 1G products. All orders placed via the EOS Data Gateway (EDG) prior to March 31, 2004 were processed by LPGS. As of March 31, 2004, access to LPGS-processed Level 1 data was transitioned to Earth Explorer and GloVis. Previous EDG users may want to select LPGS processing, to be consistent with previous data output.
- National Land Archive Production System (NLAPS) - Level 1G, Level 1P, and Level 1T products. All orders placed via Earth Explorer or GloVis prior to March 31, 2004 were processed by NLAPS. Access to NLAPS processing capability has not changed with the LPGS transition to Earth Explorer and GloVis. Previous Earth Explorer or GloVis users may want to select NLAPS processing, to be consistent with previous data output.
Note that both processing systems are capable of producing a Level 1G (systematically corrected) product. While the overall capabilities and Level 1 output from the two processing systems are very similar, users should be aware that the following differences exist:
- Product Characteristics
- There are some differences in details of the output product, such as scene edge trimming, method of band alignment, and small format differences. For a detailed comparison of the product characteristics, see: LPGS vs. NLAPS comparison
- Delivery Time
- LPGS - 1-3 days (FTP) or 1-3 weeks (media)
- NLAPS - 1-3 weeks (FTP or media)
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SLC-off Product Enhancements
The USGS/EDC has recently implemented a number of enhancements to SLC-off products and processing, some of which allow production of a fully populated ("wall-to-wall") SLC-off image. For more information, please visit the Landsat 7 SLC-off Product Enhancements webpage.
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Prices
SLC-on data products (acquisition dates prior to May 31, 2003):
| Product Type |
Price |
Availability |
Raw Uncorrected (Level 0Rp)
(single scene) |
$ 475 per scene |
General public |
Raw Uncorrected (Level 0Rp)
(multi-scene; 10 scene maximum) |
$ 475 first scene
+ $ 200 each additional scene |
General public |
Systematic Correction (Level 1G)
(single scene) |
$ 600 per scene |
General public |
Systematic Correction (Level 1G)
(multi-scene; 3 scene maximum) |
$ 600 first scene
+ $ 250 each additional scene |
General public |
Precision Correction (Level 1P)
(single scene) |
$ 725 per scene |
Approved USGS researchers only* |
Precision Correction (Level 1P)
(multi-scene; 3 scene maximum) |
$ 725 per scene
+ $ 400 each additional scene |
Approved USGS researchers only* |
Terrain correction (Level 1T)
(single scene) |
$ 800 per scene |
Approved USGS researchers only* |
Terrain correction (Level 1T)
(multi-scene; 3 scene maximum) |
$ 800 per scene
+ $ 425 each additional scene |
Approved USGS researchers only* |
*Under current USGS policy, precision- and terrain-corrected Landsat 7 products
can only be distributed to USGS researchers.
SLC-off data products (acquisition dates from May 31, 2003 to present):
| Product Type |
Price |
Availability |
Raw Uncorrected (Level 0Rp)
(single scene) |
$ 200 per scene |
General public |
Raw Uncorrected (Level 0Rp)
(multi-scene; 10 scene maximum) |
$ 200 first scene
+ $ 90 each additional scene |
General public |
Systematic Correction (Level 1G)
(single scene) |
$ 250 per scene |
General public |
Systematic Correction (Level 1G)
(multi-scene; 3 scene maximum) |
$ 250 first scene
+ $ 110 each additional scene |
General public |
Systematic (Level 1G) Gap-filled
(single scene) |
$ 275 per scene |
General public |
Precision Correction (Level 1P)
(single scene) |
$ 310 per scene |
Approved USGS researchers only* |
Precision Correction (Level 1P)
(multi-scene; 3 scene maximum) |
$ 310 per scene
+ $ 180 each additional scene |
Approved USGS researchers only* |
Terrain correction (Level 1T)
(single scene) |
$ 340 per scene |
Approved USGS researchers only* |
Terrain correction (Level 1T)
(multi-scene; 3 scene maximum) |
$ 340 per scene
+ $ 190 each additional scene |
Approved USGS researchers only* |
*Under current USGS policy, precision- and terrain-corrected Landsat 7 products
can only be distributed to USGS researchers.
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Bulk Discount
Any individual order consisting of 25 or more single scenes may qualify for a bulk discount of 20% less than the standard scene price. Bulk pricing does not apply to Landsat 7 multi-scene, SLC-off, or SLC-off gap-filled products.
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NOTE: All Landsat 7 image data acquired from July 14, 2003 (20:32:40 GMT) to present were collected in SLC-off mode. Image data acquired from 5/31/03 (21:42:35 GMT) to 7/14/03 (20:32:40 GMT) and from 9/3/03 (01:32:15 GMT) to 9/17/03 (06:22:27 GMT) are not available for search and order.
| Level of Correction |
Processing System |
Search and Order |
| Raw Uncorrected (Level 0Rp) |
n/a |
Earth Explorer
GloVis |
| Systematic Correction (Level 1G) |
NLAPS |
| LPGS |
| Systematic (Level 1G) Gap-filled |
LPGS |
| Precision Correction (Level 1P) |
NLAPS |
contact us (USGS researchers only) |
| Terrain Correction (Level 1T) |
NLAPS |
If searching by the WRS (Worldwide Reference System) of paths and rows, all Landsat 7 ETM+ data is referenced to the WRS-2 scheme.
Recently acquired scenes with direct downlink to USGS EDC will generally become available for search and order within 6-24 hours of scene acquisition.
Locations outside the U.S.: For international locations, there may be Landsat 7 scenes that were collected by the instrument but the scenes are not archived or distributed by the USGS EROS Data Center (EDC). These scenes may be available from other International Ground Stations. Note that these data would not be a product of the USGS EDC and therefore the prices, available formats, and/or processing options may vary according to the data provider.
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Landsat 7 ETM+ Dataset Transition
As of March 31, 2004, Landsat 7 ETM+ data is no longer available for search and order through the LP DAAC and the EOS Data Gateway (EDG). Although the method of data access has changed, there is no other change to the processing, format, or other details of the products.
Level 1 and Level 0 products that were previously available through the EDG are now accessed through Earth Explorer or GloVis by searching Enhanced Thematic Mapper Plus (ETM+) and then selecting Level 0Rp or Level 1G (LPGS processing) in the Shopping Basket. Level 1 products will continue to be available through both processing systems currently in use (LPGS or NLAPS), with the temporary exception of floating scenes. All floating scene (multi-scene) products must be processed by NLAPS at this time.
For more information on the Landsat 7 ETM+ dataset transition, see the Landsat 7 Transition Announcement.
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Image Previews
Landsat 7 scenes should always be previewed prior to purchase. Browse images of available scenes may be viewed by searching on Earth Explorer. For an alternative "quick and easy" browse image viewer (daytime acquisitions only), see GloVis.
Each Landsat 7 browse image is a subsampled JPEG of the raw scene data. The browse image will be displayed as a 5,4,3 (RGB)
composite with a 2% linear color stretch, based on individual scene content.
The image preview for SLC-off data will include a linework overlay and numerical scale intended to assist the user in determining the distribution of image effects associated with the SLC-off mode of acquisition.
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Landsat 7 ETM+ product samples are available for download at the Landsat 7 Sample Products webpage.
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