Different bands used in remote sensing

 

Spectral Reflectance Curve

 Spectral reflectance curve shows the relationship of electromagnetic spectrum with the associated percent reflectance for any given material.

For any given material, the amount of solar radiation that reflects, absorbs, or transmits varies with wavelength. This important property of matter makes it possible to identify different substances or classes and separate them by their spectral signatures.

In the fig 1.13, at some wavelength, dry soil reflects more energy than green vegetation does. In principal, we can recognize various kinds of surface materials and distinguish them from each other by these differences in reflectance.

What is Remote Sensing?

1) According to NASA ( National Aeronautics and Space Administration)

The acquisition and measurement of data/information on some properties of a phenomenon, object, or material by a recording device not in physical contact with the features under surveillance.

Techniques Involved - EMR, Radiometric, and scanners, lasers, radar, sonar, seismograph, magnetograph, etc.

2) According to CCRS ( Canada Centre for Remote Sensing)

It is a science or art of acquiring information about the earth's surface without actually being in contact with it. This is done by sensing and recording reflected or emitted energy and processing, analysing, and applying that information.

3) According to NRSC (National Remote Sensing Centre) India

It is a technique of deriving information about objects on the surface of the earth without physically coming into contact with them.

Each of the definitions is correct in an appropriate context.