“Remote sensing is a technique which provides up-to-date information about an area such as relief features, climate, vegetation, mineral, marine resources etc. with the help of “Sensors”, without having any direct physical contact with the objects of the area.” Remote sensing is simply the observation of an object from a distance.
Sensor is a device used in the Remote sensing, which senses the objects without having direct physical contact just like operating television or an Air Conditioner with the help of a remote control unit.
Prior to remote sensing technology various forms of aerial photography have been used to create maps of the earth’s surface since the eighteenth century. Satellite remote sensing can be traced back to themid-1940s and the launch of various rockets from White Sands in New Mexico and which contained cameras on board. The first satellite sensor dedicated to the multi-spectral remote sensing of earth’s surface was launched on July 26, 1972. Initially it was as Earth Resources Technology Satellites (ERTS). This series was renamed “Landsat” in 1975. The most recent, Landsat 7, was launched on April 15, 1999.
Indian Remote Sensing (IRS) satellite system was commissioned with the launch of IRS-1A, in 1988. IRS is the largest civilian remote sensing satellite constellation in the world providing imageries in a variety of spatial resolutions, spectral bands and swaths. The data is used for several applications covering agriculture, water resources, urban development, mineral prospecting, environment, forestry, drought and flood forecasting, ocean resources and disaster management.