Definition

A system of points with established POSITIONS or ELEVATIONS, or both, which are used as fixed references in positioning and correlating map features. Control is generally classified in four orders (with first order denoting highest quality) according to the PRECISION of the methods and instruments used in establishing it, and the ACCURACY of the resultant POSITIONS and ELEVATIONS. Often calledbasic control. Regulation or direction of a machine, electronic equipment, etc.; or the DIAL, knob, switch, etc. for performing this function. The exercise of directing influence over the movements of a craft or missile, with particular reference to changes in direction and SPEED.