Glasgow, MO (115.7 kb)
The U.S. Geological Survey's (USGS) EROS Data Center (EDC) has managed the Landsat data archive for more than two decades. This archive provides a rich collection of information about the Earth's land surface. Major characteristics and changes to the surface of the planet can be detected, measured, and analyzed using Landsat data. The effects of desertification, deforestation, pollution, cataclysmic volcanic activity, and other natural and anthropogenic events can be examined using data acquired from the Landsat series of Earth-observing satellites. The information obtainable from the historical and current Landsat data play a key role in studying changes through time.
This document provides an overview of the Landsat program and illustrates the application of the data to monitor changes occurring on the surface of the Earth. Landsat multispectral scanner (MSS) data provide a historical record of the Earth's land surface from the early 1970's to the early 1990's. Landsat thematic mapper (TM) data provide land surface information from the early 1980's to the present.
A Brief History of the Landsat Program
The idea of a civilian Earth resources satellite was conceived in the Department of Interior in the mid-1960's. The National Aeronautics and Space Administration (NASA) embarked on an initiative to develop and launch the first Earth monitoring satellite to meet the needs of resource managers and Earth scientists. The USGS entered into a partnership with NASA in the early 1970's to assume responsibility for the archive management and distribution of Landsat data products. On July 23, 1972, NASA launched the first in a series of satellites designed to provide repetitive global coverage of the Earth's land masses. Designated initially as the Earth Resources Technology Satellite-A (ERTS-A), it used a Nimbus-type platform that was modified to carry sensor systems and data relay equipment. When operational orbit was achieved, it was designated ERTS-1.
The satellite continued to function beyond its designed life expectancy of 1 year and finally ceased to operate on January 6, 1978, more than 5 years after its launch date. The second in this series of Earth resources satellites (designated ERTS-B) was launched January 22, 1975. It was renamed Landsat 2 by NASA, which also renamed ERTS-1 to Landsat 1. Three additional Landsats were launched in 1978, 1982, and 1984 (Landsats 3, 4, and 5 respectively). Each successive satellite system had improved sensor and communications capabilities.
NASA was responsible for operating the Landsats through the early 1980's. In January 1983, operations of the Landsat system were transferred to the National Oceanic and Atmospheric Administration (NOAA). In October 1985, the Landsat system was commercialized. After that date, all Landsat commercial rights became the property of Space Imaging EOSAT with exclusive sales rights to all thematic mapper (TM) data. Throughout these changes, the EDC retained primary responsibility as the Government archive of Landsat data. The Land Remote Sensing Policy Act of 1992 (Public Law 102-555) officially authorized the National Satellite Land Remote Sensing Data Archive and assigned responsibility to the Department of Interior. All Landsat data over ten years old is available from the National Archive at the EROS Data Center. In addition to its Landsat data management responsibility the EDC investigates new methods of characterizing and studying changes on the land surface with Landsat data.
Example image:
Characteristics of the Landsat System
Landsats 4 and 5 carry both the MSS and the thematic mapper (TM) sensors; however, routine collection of MSS data was terminated in late 1992. They orbit at an altitude of 705 km and provide a 16-day, 233-orbit cycle with a swath overlap that varies from 7 percent at the Equator to nearly 84 percent at 81 north or south latitude. These satellites were also designed and operated to collect data over a 185 km swath. The MSS sensors aboard Landsats 4 and 5 are identical to the ones that were carried on Landsats 1 and 2. The MSS and TM sensors primarily detect reflected radiation from the Earth surface in the visible and near-infrared (IR) wavelengths, but the TM sensor provides more radiometric information than the MSS sensor. The wavelength range for the TM sensor is from the visible (blue), through the mid-IR, into the thermal-IR portion of the electromagnetic spectrum. Sixteen detectors for the visible and mid-IR wavelength bands in the TM sensor provide 16 scan lines on each active scan. Four detectors for the thermal-IR band provide four scan lines on each active scan. The TM sensor has a spatial resolution of 30 m for the visible, near-IR, and mid-IR wavelengths and a spatial resolution of 120 m for the thermal-IR band.
All of the Landsats have been in sun-synchronous orbits with equatorial crossing times ranging from 8:30 a.m. for Landsat 1, 9 a.m. for Landsat 2, to 9:45 a.m. for Landsat 5.
The Landsat system provides for global data between 81 degrees north latitude and 81 degrees south latitude.
The Landsat platforms operate from a sun-synchronous, near-polar orbit imaging the same 185 km (115 miles) ground swath every 16 days. Thematic mapper (TM) data are received directly from Landsats 4 and 5 by a network of 16 worldwide ground stations. The United States ground station in Norman, Oklahoma, receives TM downlinks daily, and records them on high density tapes (HDTS). These HDTs are then sent to Space Imaging EOSAT's Image Processing Facility (IDPF) located in Lanham, Maryland. Also, data are transmitted via a Tracking and Data Relay Satellite (TDRS) to its ground terminal at White Sands, New Mexico, and then relayed via a domestic communications satellite (DOMSAT) to the Space Imaging EOSAT data processing facility in Norman, Oklahoma.
The TDRS System (TDRSS) satellites are in geosynchronous orbits. This configuration allowed the acquisition of MSS data for nearly all of the Earth's surface, except for an area between 50 degrees north and 67 degrees east by 50 degrees south and 82 degrees east. That area may be covered in part by data recorders at the Thailand and India ground stations.
The Space Imaging EOSAT Image Data Processing Facility in Lanham, Maryland, receives the HDTs from the Norman, Oklahoma, acquisition facility. The newly acquired data are manually and automatically screened for cloud cover and data quality through the Preprocessing and Data Classification System (PDCS). HDTs that are required for customer products continue through the image processing stream. The remaining data are stored locally for approximately six months; after temporary storage, they are permanently archived in Jessup, Maryland. The HDTs are also shipped to the EDC where they are copied and the original returned to the Space Imaging EOSAT.
Systematic correction data (SCD) is generated as follows:
- Correcting and validating the mirror scan and payload correction data- Providing for image framing by generating a series of scene center parameters
- Synchronizing telemetry data with video data
- Estimating linear motion deviation of scan mirror/scan line corrections
- Generating benchmark correction matrices for specified map projections
- Producing along- and across-scan high-frequency line matrices
The Space Imaging EOSAT Image Processing System (EIPS) has the capability to produce precision-corrected, geocoded, mosaicked, and terrain-corrected products. Insufficient control points in the Control Point Library (CPT) requires a single band (Band 4) tape be produced and processed on the Control Point Extraction System (CPES) for control point (chip) selection. Upon successful completion, the product is reprocessed via the EIPS. Digital elevation model (DEM) and digital terrain model (DTM) data are ingested through EIPS for terrain-corrected and mosaic products.
A 3-band digital data tape is provided with each film product request and is used in the Film Process Generation System (FPGS). The 3-band digital data are ingested, Look Up Tables (LUTs) are constructed, and the ordered RGB is assigned for output. The latent image is processed using a Colorfire-240. Further processing is completed per customer request and tranported via a commercial vendor. These products include: paper print, color positive, transparency, or processed negative.
The Space Imaging EOSAT initiated a Fast Format for TM digital data. The general formatting criteria follows:
Since 1972 these satellites have provided repetitive, synoptic, global coverage of high-resolution multispectral imagery. The characteristics of the MSS and TM bands were selected to maximize their capabilities for detecting and monitoring different types of Earth resources. For example, TM band 2 can detect green reflectance from healthy vegetation, and band 3 of TM is designed for detecting chlorophyll absorption in vegetation. TM band 4 is ideal for near-IR reflectance peaks in healthy green vegetation and for detecting water-land interfaces. TM band 1 can penetrate water for bathymetric mapping along coastal areas and is useful for soil-vegetation differentiation and for distinguishing forest types. The two mid-IR red bands on TM (bands 5 and 7) are useful for vegetation and soil moisture studies, and discriminating between rock and mineral types. The thermal-IR band on TM (band 6) is designed to assist in thermal mapping, and for soil moisture and vegetation studies.
Typically, TM Bands 4, 3, and 2 can be combined to make false-color composite images where band 4 represents red, band 3, green, and band 2, blue. This band combination makes vegetation appear as shades of red, brighter reds indicating more vigorously growing vegetation. Soils with no or sparse vegetation will range from white (sands) to greens or browns depending on moisture and organic matter content. Water bodies will appear blue. Deep, clear water will be dark blue to black in color, while sediment-laden or shallow waters will appear lighter in color. Urban areas will appear blue-gray in color. Clouds and snow will be bright white. They are usually distinguishable from each other by the shadows associated with the clouds.
A Landsat 4 and 5 TM scene has an instantaneous field of view (IFOV) of 30 square meters in bands 1 through 5 and band 7, band 6 has an IFOV of 120 square meters on the ground.
Landsat Orbit (29.4 kb)
TDRS Coverage Gap (8.7 kb) The resolution for the TM sensor is shown below:
Resolution
Landsats 4-5 (meters)
Band 1 30
Band 2 30
Band 3 30
Band 4 30
Band 5 30
Band 6 120
Band 7 30
Background information and status of Landsat satellites.
Satellite Launched Decommissioned Sensors Landsat 1 July 23, 1972 January 6, 1978 MSS and RBV Landsat 2 January 22, 1975 February 25, 1982 MSS and RBV Landsat 3 March 5, 1978 March 31, 1983 MSS and RBV Landsat 4 July 16, 1982 * TM and MSS Landsat 5 March 1, 1984 ** TM and MSS
* in standby mode used for range and command as of December 14, 1993.
** currently operational
The thematic mapper (TM) is an advanced, multispectral scanning, Earth resources sensor designed to achieve higher image resolution, sharper spectral separation, improved geometric fidelity, and greater radiometric accuracy and resolution than the MSS sensor. TM data are scanned simultaneously in seven spectral bands. Band 6 scans thermal (heat) infrared radiation.
Radiometric range of bands and resolution for the TM sensor (from Landsat 4 Data Users Handbook, 1984, USGS).
Wavelength Resolution Landsats 4-5 (micrometers) (meters) Band 1 0.45-0.52 30 Band 2 0.52-0.60 30 Band 3 0.63-0.69 30 Band 4 0.76-0.90 30 Band 5 1.55-1.75 30 Band 6 10.40-12.50 120 Band 7 2.08-2.35 30
Micrometers and their relationship to the electromagnetic spectrum are explained in the glossary.
The Space Imaging EOSAT Fast Format volume set contains a header file, image files, and a trailer file.
The first file on each volume, a Read-Me-First file, contains header data. It is in American Standard Code for Information Interchange (ASCII) format and adheres to ANSI and ISO standards. The header file contains a single 1536-byte ASCII record. All alphanumerics are left justified, and all numerics are right justified.
All image files contain only one TM band of image pixels. There are no header records within the image file, nor are there prefix and/or suffix data in the individual image records. Image data may be blocked or unblocked.
The blocking factor is a procedure used to minimize the number of digital tapes required to accommodate a full-scene seven-band image set. Image data are written to tape in individual records and between each record is an inter-record gap (IRG), 0.35 of an inch, separating image file records. Unblocked data contain one line of image data per tape record.
The last volume of the Fast Format image set includes a trailer file. The trailer file contains ephemeris information to compute the approximate spacecraft position for each pixel in the image. This file is in ASCII format and adheres to ANSI and ISO standards.
The structure for a single-volume and a multi-volume set are presented below. Each file is followed by an End-Of-File (EOF) marker. An End-Of-Volume (EOV) marker consists of three EOFs.
Single Volume Multi Volume
Volume Set Volume Set
Volume 1 Volume 2
Header File Header File Header File
EOF EOF EOF
Band 1 Band 1 Band 5
EOF EOF EOF
Band 2 Band 2 Band 6
EOF EOF EOF
Band 3 Band 3 Band 7
EOF EOF EOF
Band 4 BAND 4 EOV
EOF EOF Trailer File
Band 5 EOV
EOF Trailer File
Band 6
EOF
Band 7
EOF
EOV
Trailer File
To place orders and to obtain additional information regarding technical details, ancillary products, and pricing schedules, contact:
Customer Services, EROS Data CenterOnline requests for this data can be placed via the USGS Global Land Information System (GLIS). GLIS is an interactive computer system containing metadata and online samples of earth science data. GLIS allows you to review the metadata, determine product availability, and place online requests for products.
The EROS Data Center offers TM digital products on 8 mm cartridge tapes and Compact Disc Recordables, (CDRs).
The following products and prices will be offered by USGS-EDC to U.S. Governmentand its Affiliated Users (USGAU). This group is comprised of U.S. Government agencies; U.S. Government contractors; researchers involved with the U.S. Global Change Research Program and its international counterpart programs; and other researchers and international entities that have signed with the U.S. Government a cooperative agreement involving the use of Landsat data for noncommercial purposes.
All prices listed in the table are based on the TM data physically residing in the National Land Remote Sensing Data Archive (NSLRSDA) at EDC; the HDT access fee does not apply.
However, an HDT Access Fee must be added to the listed product price for all TM scenes that were acquired after October 28, 1992 and are not physically in the NSLRDA at the EDC. The HDT Access Fee is equal to $70 times the number of scenes on each HDT that must be purchased from Space Imaging EOSAT to fulfill the order. NOTE: No HDT access fee will be applied for the TM data acquired after October 28, 1992, if the data physically resides in the NSLRSDA.
DESCRIPTION PRICE
+-----------+ +-----+
TM Level 0 Raw $300.00
TM Level 1 NASA/CCRS $300.00
TM Systematic Single $425.00
TM Systematic Multiple $425.00 + $200.00 each additional scene
MSS Systematic Single $200.00
MSS Systematic Multiple $200.00 + $120.00 each additional scene
TM Map Reg. Single $600.00
TM Map Reg. Multiple $600.00 + $360.00 each additional scene
MSS Map Reg. Single $375.00
MSS Map Reg. Multiple $375.00 + $225.00 each additional scene
TM Terrain-Cor Single $900.00
TM Terrain-Cor Multiple $900.00 + $360.00 each additional scene
MSS Terrain-Cor Single $675.00
MSS Terrain-Cor Multiple $675.00 + $225.00 each additional scene
The following are the only products that will be offered by the USGS-EDC to
the General Public. The General Public has access to only 10-year and older
data and all of these data physically reside in the NSLRSDA at EDC, therefore, no HDT access fee applies.
DESCRIPTION PRICE
+-----------+ +-----+
TM Systematic Single $425.00
TM Systematic Multiple $425.00 + 200.00 each scene
MSS Systematic Single $200.00
MSS Systematic Multiple $200.00 + $120.00 each additional scene
Determine your Customer Category (general public or USGAU) and Date of
Sensing of the scene to be ordered and use the tables to determine the
distribution site (USGS-EDC or Space Imaging EOSAT).
+-----------------+----------------------+--------------------+
| | | |
|July 16, 1982 | 10 years ago | 1 year ago |
| to | to | to |
| 10 years ago | 1 year ago | Present |
+---------------+-----------------+----------------------+--------------------+
|General Public | USGS-EDC | Space Imaging EOSAT | Space Imaging EOSAT|
+---------------+-----------------+----------------------+--------------------+
| USGAU | USGS-EDC | USGS-EDC | Space Imaging EOSAT|
+---------------+-----------------+----------------------+--------------------+
Effective October 1, 1996
+--------------------+--------------------+
| July 16, 1982 | 10 years ago |
| to | to |
| 10 years ago | Present |
+---------------+--------------------+--------------------+
|General Public | USGS-EDC | Space Imaging EOSAT|
+---------------+--------------------+--------------------+
| USGAU | USGS-EDC | USGS-EDC |
+---------------+--------------------+--------------------+
Space Imaging EOSAT thematic mapper products consist of black and white and color film and paper products and various digital products.
Applications and Related Data Sets
Landsat data have been used by government, commercial, industrial, civilian, and educational communities in the U.S. and worldwide. They are being used to support a wide range of applications in such areas as global change research, agriculture, forestry, geology, resources management, geography, mapping, water quality, and oceanography. Landsat data have potential applications for monitoring the conditions of the Earth's land surface. The images can be used to map anthropogenic and natural changes on the Earth over periods of several months to more than 15 years. The types of changes that can be identified include agricultural development, deforestation, natural disasters, urbanization, and the development and degradation of water resources. The MSS archive has over 630,000 scenes with a data volume of 20 terabytes. The TM archive has over 300,000 scenes with a data volume of over 50 terabytes.
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TM Scene (59.2 kb)