Introduction to remote sensing

Abstract

Remote sensing refers to the variety of techniques that have been developed for the acquisition and analysis of information about the earth. This ‘information’ is typically in the form of electromagnetic radiation that has either been reflected or emitted from the earth’s surface. Since no single instrument is capable of detecting all of this radiation, a number of different sensors have been developed, each of which acquires energy measurements in a discrete portion of the electromagnetic spectrum. The distances from which these measurements are made vary greatly — from a few feet to thousands of miles. This capability has required the development of a wide range of sensor platforms. These platforms run the gamut from cherry pickers and tethered balloons to specially-designed high-altitude aircraft and earth-orbiting satellites (Fig. 1). Remote sensing acquisition techniques have become extremely complex.