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Satellite View of the United States |
What this map layer shows:
Simulated-natural-color images of the United States.
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Background Information |
Sample Map
The Landsat Project is a joint effort of the U.S.
Geological Survey (USGS)
and the National
Aeronautics and Space Administration (NASA). Since 1972,
NASA has developed and launched seven Landsat satellites. The USGS is responsible
for ground data reception, processing, product generation, and archiving.
The primary purpose of Landsat is to provide regular, repeated coverage
to support the analysis of changes on the Earth's land surface. Landsat
images provide a steady flow of data for use in a wide range of applications
such as global change research, agriculture, forestry, geology, mapping,
water quality, and oceanography.
Landsats 5 and 7, the two remaining operational Landsat satellites,
fly at an altitude of approximately 438 miles (705 km) and collect
data in 7 spectral bands over a 115-mile (185-km) swath. The sensors
detect reflected or emitted energy from the Earth in the visible
and near-infrared wavelengths. The satellite orbits are Sun-synchronous,
which means that the satellites move north to south on the sunlit side
of the Earth and cross the equator at the same time each day. Each
point on the Earth's land surface is imaged by Landsat once every 16
days.
The Satellite View map layers were produced from Landsat Thematic Mapper
(TM) imagery, from bands 2, 4, and 7 of the Landsat 4 (operational
from 1982-2001) and Landsat 5 satellites. The result is 200-meter-resolution
simulated-natural-color images of the United States and Hawaii. Vegetation
is generally green, with forests in darker green and grasslands, shrublands,
or vegetative tundra in lighter green. Areas of high reflectance,
including urban areas, rock, and dry bare soil, are shown in shades
of pink. Very bright areas, such as snow and ice, are colored blue.
The color of water bodies is influenced by natural and man-made factors
such as differences in depth, salinity, pollution, and sediment load,
which affect the reflectance of the area. There is one image for the
conterminous United States and one for Hawaii. The images were
developed by the National Atlas of the United States® with data provided
by the USGS Center for
Earth Resources Observation and Science (EROS).
EROS archives, processes, and distributes remotely sensed data, including
satellite images and aerial photographs, and works with agencies and
organizations around the world to support studies using remotely sensed
data.
For further information on the source data, see the Landsat
fact sheet.
Mosaics of TM images, adjusted to correct for positional accuracy and
relief displacement, and covering an area of 5 degrees latitude by
6 degrees longitude, are available through the Landsat
Orthorectified TM Mosaic page.
The National Atlas also includes 200-meter-resolution simulated-natural-color
images of the United States with relief enhanced by shading. |
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