Glossary for Geospatial Science

analog:  Information stored and processed as signal intensity or other measurement of a continuous physical variable.  Analog information processing translates and represents slight increments in data easily and conveys information by relative position without relying on the numeric value necessary to convey the same information digitally.  For example, the second hand on an analog watch “sweeps” around the dial and you can tell time on an analog watch even if it has no numbers on the face. Another example is a thermometer that displays temperature using a needle or liquid can indicate fractions of a degree, as well as provide information about relative warmth by the position of the dial or height of the liquid.  On the other hand, this continuous analog information is harder to copy, store, manipulate and reproduce dependably.  Anyone who has ever listened to a copy of a copy of a copy of a cassette tape has first-hand knowledge of analog information degradation.  For this reason, much analog information (video, audio, or field and laboratory measurements of temperature, pressure, voltage, radiation, and so on) is converted to its digital equivalent.  (See also: digital, digitizer)