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| USGS › Geography › Earth Resources Observation and Science (EROS) Center |
Landsat TM Image (San Diego, CA) |
The Landsat Thematic Mapper (TM), a sensor carried onboard Landsats 4 and 5, has acquired images of the Earth nearly continuously from July 1982 to the present with a 16-day repeat cycle.
Landsat TM image data files consist of seven spectral bands (band designations). The resolution is 30 meters for Bands 1-5, and Band 7. Band 6 resolution (thermal infrared) is a collected 120 meters, but is resampled to 30 meters. The approximate scene size is 170 km north-south by 183 km east-west (106 mi by 114 mi).
| Product Type | L1T Terrain Corrected* |
|---|---|
| Pixel Size | 30-meter reflective: Bands 1-5 and 7 60-meter thermal: Band 6 |
| Output Format | GeoTIFF |
| 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 | |
| Immediate for scenes already processed and ready for download. Most Landsat 4-TM scenes take 1 to 3 days to process; some Landsat 4 TM scenes take 3 days to 1 week. |
* While most Landsat TM 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 below for details on the levels of correction.)
Additionally, a select number of Landsat TM scenes are processed with only Systematic Correction (Level 1G) due to processing constraints. Improvements to production capabilities are being investigated and, when employed, will allow more scenes to be processed at a higher correction level with a shorter processing time.
Specific Level 1T scenes are available for most of the globe under the Global Land Surveys (GLS) of 1975, 1990, 2000, and 2005. These datasets can be found on on GloVis or EarthExplorer.
Most Landsat 4-5 TM scenes are processed through the Level 1 Product Generation System (LPGS); however, some TM scenes are processed through the National Land Archive Production System (NLAPS).
(All Landsat 4 TM scenes were processed through NLAPS prior to April 15, 2009). More information on these systems can be found at
http://landsat.usgs.gov/products_IP_LPGSvsNLAPS.php
On April 2, 2007, updates to the radiometric calibration of Landsat 5 (L5) Thematic Mapper (TM)
data processed and distributed by the USGS EROS created an improved Landsat 5 TM data product that
is now more comparable to Landsat 7 Enhanced Thematic Mapper Plus (ETM+) radiometrically, and
provides the basis for continued long-term studies of the Earth's land surfaces. For more information, please visit:
http://landsat.usgs.gov/science_calibration.php
Landsat TM scenes are referenced to Landsat Worldwide Reference System -2 WRS-2
Landsat TM scenes held in the USGS archive can be searched using EarthExplorer or the USGS Global Visualization Viewer GloVis. (Only scenes with browse capability can be searched and ordered on GloVis.)
New TM scenes generally become available for search and order within 6 to 24 hours after data acquisition. To view real-time acquisitions of Landsat over the United States, please visit EarthNow!
Some Landsat 5 TM scenes of areas outside the United States are not archived or distributed by USGS EROS. These scenes may be available from International Ground Stations (IGSs). IGS data are not products of USGS EROS and therefore prices, available formats, and processing options may vary according to the data provider.
Data is delivered from the USGS only in digital format; there are several commercial firms that can provide printed images from the USGS digital data
Landsat TM image previews are available on EarthExplorer or GloVis. Each browse image is a resampled JPEG of the raw scene data, and is displayed as a 5,4,3 (RGB) composite with a standardized 2% linear stretch applied.
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