In the broadest scene, the measurement or acquisition of information of some property of an object or phenomenon, by a recording device that is not in physical or intimate Contact with the object or phenomenon under study; for instance, the utilization at a distance (as from aircraft, spacecraft, or ship) of any instrument and its attendant recording and display devices for gathering information pertinent to the environment such as measurements of force fields; electromagnetic radiation, or acoustic energy. The technique employs such devices as cameras, lasers, radio Frequency receivers, Radar systems, sonar seismographs, gravimeters, magnetometers, multispectral scanners, and scintillation counters.