An Overview of Remote Sensing

Remote Sensing is an extensive science, drawing from many areas for support and development. It depends greatly on the support of governments and private industries worldwide. Satellite and digital imagery play an important role in remote sensing; providing information about the land studied.

definition of remote sensing

An Introduction
Remote Sensing is the science and art of acquiring information (spectral, spatial, temporal) about material objects, area, or phenomenon, without coming into physical contact with the objects, or area, or phenomenon under investigation. Without direct contact, some means of transferring information through space must be utilised. In remote sensing, information transfer is accomplished by use of electromagnetic radiation (EMR). EMR is a form of energy that reveals its presence by the observable effects it produces when it strikes the matter. EMR is considered to span the spectrum of wavelengths from 10-10 mm to cosmic rays up to 1010 mm, the broadcast wavelengths, which extend from 0.30-15 mm.


Types

1. In respect to the type of Energy Resources:
   Passive Remote Sensing: Makes use of sensors that detect the reflected or emitted electro-magnetic radiation from natural sources.
   
   Active remote Sensing: Makes use of sensors that detect reflected responses from objects that are irradiated from artificially-generated energy sources, such as radar.
   
2. In respect to Wavelength Regions:
   
   Remote Sensing is classified into three types in respect to the wavelength regions
   • Visible and Reflective Infrared Remote Sensing.
   • Thermal Infrared Remote Sensing.
   • Microwave Remote Sensing.