Remote sensing
- Contents
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[ Definition | Characteristics | Satellite | Applications | References ]
- Definition
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sensu lato The measurement or aquisition of information of some property of an object or phenomenon by a recording device that is not in physical or intimate contact with the object or phenomenon at a distance.
sensu strict The technique employs such devices as the camera, lasers, radio frequency receivers, radar systems, sonar, seismographs, gravimeters, mangetometers, and scintillation counters.
- Characteristics of sensors
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Table. 1. Major attributes of remotely sensed data (McGraw et al. 1998)
Attribute Explanation Radiometric Number of shades of grey levels and range of brightness values sensed Spectral Number of wavelength bands and the extent of the electromagnetic spectrum sensed Spatial Size of the smallest object that can be resolved and the total area imaged Temporal Period between image collection of the same site and total period of image collection HYDICE (hyperspectral digital imagery collection experiment: resolution = 0.75 m, 210 bands)
- Satellite
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Table. Comparisons between major satellites for measuring land surface characteristics. obs: observation. wl: wavelength. res: resolution ability satellite country rotation (d) launch yr discard observed width sensor obs. wl (nm) res (m) SPOT1
SPOT2
SPOT3
SPOT4
SPOT5France 26
26
261986.2
1990.1
1993.9
1998.3
2002.51990.12
1997.1160 km × 2 HRV1
HRV2
HRV3
HRV4500-590
610-680
790-890
510-73020
20
20
10SPOT USA 26 1998 HIVIR/VGT LANDSAT1
LANDSAT2
LANDSAT3USA 17-18 1972.7
1975.1
1978.31978.1
1982.2
1983.3185 km MSS4
MSS5
MSS6
MSS7500-600
600-700
700-800
800-110080
80
80
80LANDSAT4
LANDSAT5USA 16/17 1982
1984
1993185 km TM1
TM2
TM3
TM4
TM5
TM7
TM6450-520
520-600
630-690
760-900
1550-1750
2080-2350
10.4-12.5 µ30
30
30
30
30
30
120LANDSAT7 USA 16 1999 ETM+ 500-900 15 MOS-1
MOS-1bJapan 23 1987.2
1990.21995.3
1996.4100 km × 2 MESSR1
MESSR2
MESSR3
MESSR4510-590
610-690
720-800
800-110050
50
50
50IRS-1 India 22 1988 146 km LISS1
LISS2
LISS3
LISS4450-520
520-600
630-690
760-90072.5
72.5
72.5
72.5NOAA* USA 1/2 1978 2700 km AVHR1
AVHR2
AVHR3
AVHR4580-680
725-1100
3550-3930
11.5-12.5 µ1.1 km
1.1 km
1.1 km
1.1 kmIKONOS 1999 MS/P** 4
1QuickBird-2 2001 MS/P 2.4
0.6EOS-AM1*** < 1 1999 2330 km MODIS R/NR 250 *: National Oceanic and Atmospheric Administration
**: multi-spectrum/panchromatic
***: Terra that loads ASTER - Applications
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NDVI
Leaf area index
APAR
FPAR
evapotranspiration - References
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- Earth Observation Center
- geographic information system, GIS
- normalized difference vegetation index, NDVI
Remote Sensing, RS
Web sources in Japanese
Recently, RS is tightly connected with GIS. Distinction between RS and GIS is often useless.