Sensor Description... LANDSAT-7
Background... Landsat is the United States' oldest land-surface observation satellite system.
The program has scored numerous successes in scientific and resource-
management applications over its 26-year history and the Landsat 7 satellite
marks a new direction to reduce the costs of data and increase worldwide
coverage for use in global change research.
As part of NASA's EOS series of satellites, Landsat 7 provides a unique suite of
medium-resolution observations of the terrestrial environment. These
observations allow for investigations into the causes of land-surface change.
Landsat 7 gathers remotely sensed images of land surface and coastal regions
for global change research, regional environmental change studies, national
security uses, and other civil and commercial purposes. The Landsat 7 project is
part of NASA's long term, coordinated research effort to study the Earth as a
global environmental system.
The instrument on board Landsat 7 is the Enhanced Thematic Mapper Plus
(ETM+). ETM+ is a passive sensor that measures solar radiation reflected or
emitted by the Earth's surface. The instrument has eight bands sensitive to
different wavelengths of visible and infrared radiation and has better resolution in
the thermal infrared band than the Thematic Mapper (TM) instrument carried by
Landsats 4 and 5. The instrument's calibration is good to within 5 percent,
making the ETM+ far more accurate than its predecessors.
Landsat 7 data is used to build and periodically refresh a global archive of sun-lit,
essentially cloud-free images of the Earth's landmass. With an upgraded data
system on the ground, Landsat 7 can collect 250 scenes per day, each scene
containing enough digital data to fill a powerful home computer's hard drive.
Launched on April 15th 1999, LANDSAT 7 began its mission to continue and
augment the 27-year record of Earth-observation data begun by LANDSAT 1 in
1972. Enhanced instrument features in the LANDSAT 7 design allow monitoring
of global, regional, as well as small-scale features and processes on the Earth's
surface. Change detection studies for environmental, urban, or other applications
are advanced by LANDSAT's range of spectral and spatial resolutions.
Use LANDSAT 7 for:
- Environmental monitoring
- Geological and hydrological analysis
- Agriculture, forestry, and natural resources monitoring
- Land use classification and mapping
- Coastal resources
- GIS backdrops and land surface analysis
What are the uses of LANDSAT 7 data?
Over its 27-year history, LANDSAT data has been demonstrated in a variety of
Applications for LANDSAT 7 ETM+ data include:
??Agriculture, Forestry, and Range Resources including discriminating
vegetative crop and timber types; measuring crop and timber acreage; precision
farming land management; monitoring crop and forest harvests; determining
range readiness, biomass and health; determining soil conditions; monitoring
desert blooms; assessing wildlife habitat; characterizing forest range vegetation;
monitoring and mapping insect infestations; and monitoring irrigation practices.
>> Land Use and Mapping including classification of land uses; cartographic
mapping and map updating; categorizing land capabilities; monitoring urban
growth; aiding regional planning; mapping transportation networks; mapping
land-water boundaries; siting transportation and power transmission routes;
planning solid waste disposal sites, power plants, and other industries; mapping
and managing flood plains; and tracking socio-economic impacts on land use.
>> Geology including mapping major geologic features; revising geologic maps;
recognizing and classifying certain rock types; delineating unconsolidated rocks
and soils; mapping volcanic surface deposits; mapping geologic landforms;
identifying indicators of mineral and petroleum resources; determining regional
geologic structures; producing geomorphic maps; and mapping impact craters.
>> Hydrology including determining water boundaries and surface water areas;
mapping floods and flood plain characteristics; determining area extent of snow
and ice coverage; measuring changes and extent of glacial features; measuring
turbidity and sediment patterns; delineating irrigated fields; monitoring lake
inventories and health; estimating snow melt runoff; characterizing tropical
rainfall; and mapping watersheds.
>> Coastal Resources including determining patterns and extent of coastal
turbidity; mapping shoreline changes; mapping shoals, reefs, and shallow areas;
mapping and monitoring sea ice in shipping lanes; tracking beach erosion and
flooding; monitoring coral reef health; determining coastal circulation patterns;
measuring sea surface temperature; and monitoring and tracking 'red' tides.
>> Environmental Monitoring including monitoring deforestation; monitoring
volcanic flow activity; mapping and monitoring water pollution; determining
effects of natural disasters; assessing drought impact; tracking oil spills;
assessing and monitoring grass and forest fires; mapping and monitoring lake
eutrophication; monitoring mine waste pollution; and monitoring volcanic ash
- launched in 1999.
- seven spectral bands and one panchromatic band
- wide swath width (185 km)
- 15-metre, 30-metre, 60-metre, and 80-metre resolution
- 705km sun-synchronous orbit
- 16 day repeat cycle
- single nadir-pointing instrument (ETM+ sensor)
Landsat-7 data are collected from a nominal altitude of 705 kilometers in 183-
kilometer swaths, providing global coverage.
Platform: Near-polar orbiting system Sensor: Latitude coverage--81 degrees north
to 81 degrees south Longitude coverage--180 degrees east and west Spatial
The following table on band characteristics contains information on spatial
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