![]() The latest commercial satellite (GeoEye 1) has a GSD of 0.41m (effectively 0.5 due to US Govt restrictions on civilian imaging). For example, the GSD of Landsat is ~30m, which means the smallest unit that maps to a single pixel within an image is ~30m x 30m. GSD is a term containing the overall optical and systemic noise sources and is useful for comparing how well one sensor can "see" an object on the ground within a single pixel. Geometric resolution refers to the satellite sensor's ability to effectively image a portion of the Earth's surface in a single pixel and is typically expressed in terms of Ground Sample Distance, or GSD. Radiometric resolution refers to the effective bit-depth of the sensor (number of greyscale levels) and is typically expressed as 8-bit (0-255), 11-bit (0-2047), 12-bit (0-4095) or 16-bit (0-65,535). There are two different types of resolution when discussing satellite imagery: radiometric, and geometric. Satellite imagery has also used in seismology and oceanography in deducing changes to land formation, water depth and sea bed, by colour caused by earthquakes, volcanoes, and tsunamis. For example ESL Incorporated developed some of the earliest two dimensional Fourier transforms applied to digital image processing to address NASA photos as well as national security applications. Some of the first image enhancement of satellite photos was conducted by the U.S. Interpretation and analysis of satellite imagery is conducted using software packages like ERDAS Imagine or ENVI. There are also elevation maps, usually made by radar imaging. Images can be in visible colours and in other spectra. Satellite images have many applications in agriculture, geology, forestry, biodiversity conservation, regional planning, education, intelligence and warfare. or to map a small area of the Earth, such as this photo of the countryside of Haskell County, Kansas, United States. In the early 21st century satellite imagery became widely available when affordable, easy to use software with access to satellite imagery databases became offered by several companies and organizations. There are also private companies that provide commercial satellite imagery. Several other countries have satellite imaging programs, and a collaborative European effort launched the ERS and Envisat satellites carrying various sensors. In 1977, the first real time satellite imagery was acquired by the USA's KH-11 satellite system.Īll satellite images produced by NASA are published by Earth Observatory and are freely available to the public. Landsat 7, the most recent Landsat satellite, was launched in 1999. Also in 1972 the United States started the Landsat program, the largest program for acquisition of imagery of Earth from space. The Blue Marble photograph was taken from space in 1972, and has become very popular in the media and among the public. The first satellite photographs of the Moon might have been made on Octoby the Soviet satellite Luna 3, on a mission to photograph the far side of the Moon. First satellite photographs of Earth were made Augby the US satellite Explorer 6. Both distinct mosaics were produced by using different spectral bands.First television image of Earth from space transmitted by the TIROS-1 weather satellite. Ortho-rectified mosaics with 25 pixel resolution are comprised from 369 satellite scenes taken between July 1999 and September 2000.View/ Purchase ASTER, EO-1, Landsat 35 year Archive, MODIS, & TerraLook (free download from Landsat Archive complete by 2/09).USGS Global Visualization Viewer (GLOVIS).The WAGDA website hosts some digital aerial photography and links to others.Washington State geospatial data archive.The Landsat images have been ortho-rectified, tonally balanced, mosaicked, tiled, and wavelett compressed. This worldwide set of 770 satellite imagery mosaics, marketed as 2000 GeoCover by Land Info Worldwide Mapping, is from Landsat 7 Enhanced Thematic Mapper (ETM+) the 15m band was pan-sharpened with 30m multi-spectral bands 7-4-2.This near-worldwide set of 609 satellite imagery mosaics, marketed as 1990 GeoCover by Land Info Worldwide Mapping, is from Landsat 4/5 TM and includes three 30m multi-spectral bands 7-4-2.Multispectral (30 m), Thermal (60 m), Panchromatic (15 m).Leveraging Landsat satellite imagery and Shuttle Radar Topography Mission data, World Wind lets you experience Earth terrain in 3D. World Wind lets you zoom from satellite altitude into any place on Earth.
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