The process of detecting and monitoring the physical characteristics of an area by measuring its reflected and emitted radiation at a distance from the targeted area. Remote sensing is used in this thesaurus to refer to methods that are solely or primarily deployed through air or space. Included in this concept are studies of biological populations using remote imaging techniques. Related methods which are used most frequently on the ground (e.g. photography), whether underwater, from airplanes or satellites, are not included in the term "remote sensing."