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.

The following table summarises the main characteristics of the network.

PurposeTo provide marks to enable users to connect to official vertical datums

Across North Island, South Island, Stewart Island/Rakiura

Sufficient density along existing levelling routes to enable efficient connection to official vertical datums

AccuracyOrder: 1V (vertical only)
Tier: E (0.25 m)
Class: VI (0.01 m, 3x10-6m/m)
Class evaluation radius: 2 km
Mark characteristics

Precise levelling

Ideally included as part of another network


Sited so that surveyors can easily and safely locate and occupy

Mark AccessPhysical access to collect conventional observations
Last Updated: 31 August 2017