Remote Sensing

 Explain the principle of remote sensing method for exploring the natural resources.
 What is Remote Sensing? Write its objectives. 

•  It is the techhique of collecting information about any object without making a physical contact with it.
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• Objectives of remote sensing are: 

• application of space technology 
• Groundwater surveys 
• Forest surveys
•  Preparing wasteland maps 
• Mines and mineral resources surveys
•  Estimation of crop yields
•  Detection of crop diseases 
• Assessment of drought
•  Spying for military purposes
•  Detection of potential fishing zones, etc.

1.  Remote sensing is a method of collecting information about ground objects like soil, water, vegetation and minerals from a remote place such as an aircraft or a satellite.
2.  This technique not only enables us to locate various resources but also helps us to know about their quantity and quality. 
3. This method is used to collect information about an object, without physical contact with that 
4. object. 
5. The simplest device could be a camera carried by an aeroplane to photograph large areas of land systematically.
6.  Television cameras could be mounted on satellites and they could take pictures showing details of clouds, water, forests or buildings methods of remote sensing because visible light is used by the cameras 
7. But one could send out radio waves from the satellites and observe how they are reflected of absorbed on the surface of the earth.
8.  Usually radio waves of wavelengths as small as a few centimeters called 'microwaves, are used for such studies, because these waves penetrate through clouds and their reflections also go through the clouds to reach the satellite. 
9. Similarly, infra-red signals can be sent from the satellite and reflections studied to reveal the nature of the reflecting surface. 
10. The orbit of a sun-synchronous satellite is such that it always poses over a particular place on the earth at almost the same local time.
11.  It means whenever the satellite passes over a certain place on the earth, the position on the earth. "
12. of the sun relative to that place is always the same.
13.  Thus, the cameras of that satellite are enable to get photographs of that place always with nearly the same illumination every time it passes over that place.