Any of a set of two or more measurement systems used to determine the position of a point, line, curve, or plane on the globe with respect to a system of lines or other fixed reference. A coordinate system is usually defined by a map projection (its units and characteristics), a spheroid of reference, a datum, one or more standard parallels, a central meridian, and possible shifts in the x and y directions. It is used to locate x,y positions of point, line, and area features.