Geodetic control network

A geodetic control network is a network, often of triangles, that are measured precisely by techniques of control surveying, such as terrestrial surveying or satellite geodesy. It is also known as a geodetic network, reference network, control point network, or simply control network.

A geodetic control network consists of stable, identifiable points with published datum values derived from observations that tie the points together.

Classically, a control is divided into horizontal (X-Y) and vertical (Z) controls (components of the control), however with the advent of satellite navigation systems, GPS in particular, this division is becoming obsolete.

In the U.S., there is a national control network called the National Spatial Reference System (NSRS).

Many organizations contribute information to the geodetic control network.

The higher-order (high precision, usually millimeter-to-decimeter on a scale of continents) control points are normally defined in both space and time using global or space techniques, and are used for "lower-order" points to be tied into. The lower-order control points are normally used for engineering, construction and navigation. The scientific discipline that deals with the establishing of coordinates of points in a control network is called geodesy.