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Learn about satellite systems like MODIS, ASTER, SPOT, IKONOS, and Quickbird used for Earth observation. Understand their capabilities, resolutions, and data acquisition to enhance environmental monitoring and mapping.
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OTHER Satellite Systems MODIS ASTER SPOTIKONOSQUICKBIRD?
Earth Observation System (EOS) • “terra” and “aqua” are the actual satellites… • Terra (EOS AM) and Aqua (EOS PM) • ‘Terra's’ orbit around the Earth is timed so that it passes from north to south across the equator in the morning • ‘Aqua’ passes south to north over the equator in the afternoon • http://ivanova.gsfc.nasa.gov/outreach/Terra_CD-01/start.htm
MODIS (Moderate Resolution Imaging Spectroradiometer ) • detectors measure 36 spectral bands between 0.405 and 14.385 µm • viewing swath width of 2,330 km and views the entire surface of the Earth every one to two days • acquires data at three spatial resolutions -- 250m, 500m, and 1,000m • http://modis.gsfc.nasa.gov/data/
MODIS data • 12 bit data in 36 spectral bands • 28= 8 bit data = 256 unique • 212=12 bit data = 4096 unique values • http://modis.gsfc.nasa.gov/about/specs.html
The advantage of 12 bit data…. Higher digital resolution Higher display resolution…. Except that humans can ‘only’ discriminate between 10 million colors
ASTER (Advanced Spaceborne Thermal Emission and Reflection Radiometer) • The spatial resolution varies with wavelength: • 15 m in the visible and near-infrared • 30 m in the short wave infrared • 90 m in the thermal infrared (TIR). Each ASTER scene covers an area of 60 x 60 km.
Systeme Pour l’Observation de la Terre (SPOT) • French Satellite system • Commercial orientation • 2.5-20 meter pixel resolution • Pushbroom scanner • Off nadir viewing capability (stereo images)
IKONOS • launched in September 1999 • Normal scene 11km X 11 km • 4 channels of multispectral data at 4 m resolution • one panchromatic channel with 1 m resolution • 11 bits per pixel (2048 values)
Quickbird • Launched October 18, 2001 • 11 bit data • 61-cm (2-ft) panchromatic Panchromatic • (Black & White) 445 to 900 nanometers • 2.44-m (8-ft) multispectral • Blue: 450 to 520 nanometers • Green: 520 to 600 nanometers • Red: 630 to 690 nanometers • Near-IR: 760 to 900 nanometers