Comprehensive Remote Sensing, Volume 9:Applications for Societal Benefits

Remote sensing (RS) refers to the science of sensing an object without being in physical contact with it. This is achieved by placing sensors onboard a spacecraft, aircraft, a balloon or an unmanned aerial vehicle, which detect reflected and/or emitted radiation from objects/earth surface features in different spectral regions. Data thus obtained are analysed to identify and characterize the earth surface features. The basic premise is that every object/earth surface feature reflects and/or emits electromagnetic radiation differently at different wavelengths. Space-borne RS began almost five decades ago with the launch of LANDSAT 1 by USA in 1972. Since then, many RS satellites carrying sensors operating in different parts of the electromagnetic radiation (visible, infrared, microwave), at different spatial resolution and frequency of observation have been launched by several countries. Data obtained by these satellites have been extensively used to map the entire earth surface, study natural resources such as agriculture, forestry, water resources, coastal zone, snow and glaciers, land forms, etc. for weather prediction and ocean state forecasting. Data obtained at different time intervals have allowed us to study how the resources have changed over a period of time and also to evolve measures for their conservation and sustainable development.