The basic principle of remote sensing is that the different objects based on their structural, chemical and physical properties return (reflects or emits) different amount of energy in different wavelength ranges (commonly referred to as bands) of the electromagnetic spectrum incident upon it.
Most remote sensing systems utilize the sun’s energy, which is a predominant source of energy. These radiations travel through the atmosphere and are selectively scattered and/or absorbed depending upon the composition of the atmosphere and the wavelengths involved. These radiations upon reaching the earth’s surface interact with the target objects.
Everything in nature has its own unique pattern of reflected, emitted or absorbed radiation. A sensor is used to record reflected or emitted energy from the surface. This recorded energy is then transmitted to the users and then it is processed to form an image, which is then analyzed to extract information about the target.
Finally the information extracted is applied to assist in decision making for solving a particular problem.