National Reference Frame

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

This page summarises the main characteristics of the network.


To enable the link between official geodetic and vertical datums and international reference systems to be determined and monitored.


At least one geodetic datum reference mark (GDRM) on the stable part of each tectonic plate (Pacific, Australian, Antarctic)

Vertical datum reference mark (VDRM) to be co-located with each GDRM


Order: 0
Tier: Horiz A (0.05 m), Vert A (0.05 m)
Class: Horiz II (0.003 m, 3x10-8m/m), Vert II (0.003 m, 3x10-8m/m)
Class evaluation radius: all NRF marks

Mark characteristics

GDRM normally continuous GNSS

VDRM normally absolute gravity

May co-locate with other observation systems (VLBI, DORIS)


To enable GNSS collection (GDRM)

To enable absolute gravity collection (VDRM)

Mark access

Data available from LINZ website

No physical access to mark