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.

Key Capabilities

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.

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 plumes.

Overview

• 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)

Data Description:

Spatial Characteristics:

Landsat-7 data are collected from a nominal altitude of 705 kilometers in 183- kilometer swaths, providing global coverage.

Spatial Coverage:

Platform: Near-polar orbiting system Sensor: Latitude coverage--81 degrees north to 81 degrees south Longitude coverage--180 degrees east and west Spatial Resolution:

The following table on band characteristics contains information on spatial resolution.