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 geodetic markers, which are stable, identifiable points or vertices with published coordinate values derived from observations that tie the points together.

In the U.S., there is a national control network called the National Spatial Reference System (NSRS). Many organizations may contribute information to the geodetic control network. In the United Kingdom, the Ordnance Survey maintains the OS Net 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.