Landsat
7 Sensor ( ETM+)
The Band 6 on Landsat 7 is divided into two bands, high and low gain, Images in two modes
• Panchromatic Image : operating in visible & near infra red region.(15m Resolution) TM band 1 for
Bathymetry ,Solid vegetation, Different forest types identification.
• Multispectral Images: obtain image data in 7 bands of visible, Near IR & Middle IR region. (30 m
Resolution)
Two mid IR bands on TM are useful for vegetation and soil moisture status, discriminating soil and rock
Far IF band for soil mapping, soil moisture and vegetation study.This system currently operated by US Geo survey. As result of this image capturing techniques image cost dropped down. They have seven LANDSAT satellites, the first launched in 1972. Landsat 5 and Landsat7 are in operational. Land sat has multispectral sensors Multi spectral Scanner(MSS) and Thematic Mapper(TM). MSS has 80m and TM has 30m resolution.
Spectral
Resolution (µm) Band Spatial Resolution(m)
Band 1 0.450 – 0.515
Band 2
0.525 – 0.605
Band
3 0.630 – 0.690
Band
4 0.760 – 0.900
Band
5 1.550 – 1.750
Band
6† 10.40 – 12.5
Band
7 2.080 – 2.35
Band
8 0.52 – 0.92
Blue
-Green 30
Green 30
Red 30
Near
IR 30
Mid
IR 30
ThermaL
IR 60
Mid
IR 30
Pan 15
SPOT
2.5m
This is main earth
observation satellites operated by French since 1985. This system has two
sensors, Multispectral or panchromatic mode. Multispectral image have 20m and
panchromatic mode has 10m resolution. It has three multi spectral bands, Green,
Red and Infrared. It aunched in 1998. SPOT is the only satellite system acquire
stereo satellite imagery.
ISR
This is Indian Remote Sensing Satellite
has 5 satellites system, Launch in 1995 to 2004. This is main earth observation
satellite. Spatial resolution 5.8m to 23.8m
FCC –
3,2,1 PNCC – 2,3,1
QuickBird
0.6m
Canyon Lands, UT (0.6 m
resolution) April 20, 2003. Launched in 18
OCT,2001, operated by DIGITALGLOBE, 450 km orbit, sun-synchronous, 1-3.5 day
revisit period, 0.61 m- 0.72 panchromatic, 2.44 m-2.88M multispectral. Spectral
Pan – 1, MS – 4. Radimetric 11bit
Band
1 – Blue 0.45-0.52, Band 2 – Green 0.52-0.6, Band 3 – Red 0.631 – 0.691, Band 4
– NTR 0.76 – 0.9
IKONOS
(4 m Multispectral)
Launched by Space Imaging in 1999, 1 m panchromatic and 4 m multispectral
resolution, 681 km orbit, crosses equator between 10 and 11 am daily, revisit
1.5-3 days.
RADAR
(Radio Detection and Ranging)
SLAR (Side looking Airborne Radar) developed by military in
1950’s, and SAR (Synthetic aperture radar), Image is NASA TOPSAR of Pasadena
valley, CA.
LIDAR
(Light Detection and Ranging)
Image: Bainbridge Island, WA courtesy Pudget Sound LIDAR
Consortium, 2005
ALOS
Advanced Land Observation
Satellite system. ALOS launch in 2006. This is an Earth observation satellite.
Spatial resolution 10m
Pre-image Procession
Prior to data analysis, initial processing
on the raw data is usually carried out to correct for any distortion due to the
characteristics of the imaging system and imaging conditions. Its depend on the
user's. These procedures include radiometric correction and field of view of
the sensor.