What is Remote Sensing?
Remote sensing is the science of obtaining information about objects or areas from a distance, typically from aircraft or satellites.
Remote sensing is science and art of acquiring information about an object without physical contact with it. Though human sights and photographs are common examples of remote sensing, in civil engineering we restrict its meaning to sensing of the objects on the earth from satellites using electromagnetic energy. Most of the remote sensing methods make use of the reflected microwaves, infrared rays and visible light waves in the electromagnetic spectrum. When the electromagnetic waves sent from satellites strike the earth surface, its characters change due to transmission, absorption, emission, scattering and reflection. Since each feature on the earth has different characters, it is possible to identify the feature on the earth with satellite pictures. Remote sensing is mostly qualitative in nature. Data obtained from satellite is to be analysed by user and correctly identify the objects. This is called image processing. India has its own remote sensing satellites such as INSAT series, PSLV series etc.
Major area of application of remote sensing is for the following: 1. Resource exploration 2. Environmental study 3. Land use identification and 4. For assessing and predicting natural hazards. Nowadays this area of civil engineering is fast developing and many engineers are employed for this work.