Survey Control Networks

The NRF provides the connection between national geodetic and vertical datums, and international reference systems.

The DMN monitors national-scale tectonic deformation and monitors regional and local-scale deformation to maintain the NZGD2000 deformation model, to maintain the other control networks for the effects of deformation and to re-establish the other control networks following a major deformation event.

The CHN provides the street-level control marks that are used by surveyors to connect to and orient cadastral surveys in terms of the official geodetic datum (NZGD2000).

The CVN provides the street-level control marks that are used by surveyors to connect cadastral surveys to the official vertical datum (NZVD2016).

The BGN provides a national coverage of control marks (including the offshore islands and Antarctica) to enable users to efficiently connected to official geodetic and vertical datums.

The NHN ensures that important precise levelling control marks are retained and that geometric heights are determined for new control marks when they are established. This enables users to connect their datasets to the official geodetic datum.