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.
|Purpose||To 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
|Accuracy||Order: 1V (vertical only)|
Tier: E (0.25 m)
Class: VI (0.01 m, 3x10-6m/m)
Class evaluation radius: 2 km
Ideally included as part of another network
Sited so that surveyors can easily and safely locate and occupy
|Mark Access||Physical access to collect conventional observations|