Remote Sensing
Introduction-
Remote Sensing is the science and art of getting information about an object over the earth surface without making any physical contact.
Remote sensing is used in numerous fields, including geography, land survey and most Earth
science disciplines like ecology, meteorology, oceanology, glaciology, geology. It also has military, intelligence, commercial, economic, planning and humanitarian application.
EMR -
In recent times, term "Remote sensing" means to use of satellite sensor technology to detect reflecting intensity of any part of the earth surface, atmospheric layers by analyze Electro Magnetic Radiation (EMR).
Process -
It can follow some sequential process like flow diagram. Solar radiation in the form of EMR reflected or refracted by surface and particales of the atmosphere. such reflection has been received by satellite sensor (Active or Passive) and transmitted to the data recording center.
Data has been corrected by using OBIA (Object Based Image Analysis), atmospheric correction like elimination of haze, changing gray values of pixel. Radiometric and Topographical correction are also available by monochromatic scale analysis, terrain analysis respectively. Like way final data products are prepared and used in field level.
Resolution -
Some sensors are placed in satellite, used only in day time, known as Passive sensor and some others
can be used in night also called Active sensor. Clarity of image is based on Spatial, Spectral, Radiometric resolution of the sensor where Temporal resolution represent frequency of satellite scan over the earth surface.
Data processing levels are initially defined by NASA in 1986 during it's EOS technique which starts with 0 level followed by 1a, 1b,2,3,4 levels.
History -
Picturisation of earth surface was started soon after World War I by military surveillance through aerial photograph. Different camera were used in aircraft to capture photograph of the earth surface, though it was costly enough having lots of weather disturbance.
After invention of satellite imagery concept by designing polar and sun-synchronous satellite remote sensing got immense importance in different domain of application.
Application -
Application of Remote sensing is in various areas like....
- Conventional RADAR was used in aerial traffic control but Doppler RADAR is used in meteorological analysis.
- Laser and Radar altimeters are used in ocean wave and current analysis.
- LIDAR is used to detect chemical reaction in atmosphere.
- Hyperspectral Imaging is used in mineralogy, biology, defense and environmental issues.
- Basic photogrammetry technique is used in all type topographical analysis over the earth surface.
Training and education opportunities are available in European and North American countries like France, Netherlands, USA, Canada but country like India has developed its Space Science through ISRO.
There are different sister organisations of ISRO like NRSC, IIRS serve the nation for advancement of such modern technology. These institutions give opportunity to young Indian and foreign nationals to develop their knowledge in
Apart from these central govt. organisation, lots of IIT like Kharagpur, Roorkee, Mumbai, different Universities also offer various courses on Remote sensing.
