Cadastral Vertical Control Network
The CVN provides the street-level control marks that are used by surveyors to connect cadastral surveys to the official vertical datum (NZVD2016).
Most cadastral surveys do not include heighted boundaries, of those that do many will be defined as ‘permanent structure boundaries” which do not need to be in terms of an official vertical datum. CVN marks will primarily be required in urban areas where multi-level developments are occurring or are likely to occur. The following table summarises the main characteristics of the network.
| Purpose | To provide marks to enable cadastral surveyors to efficiently connect to the official vertical datum |
|---|---|
| Density | Across North Island, South Island, Stewart Island/Rakiura Sufficient to enable surveys to be connected to official datums |
| Accuracy | Order: 5 (vertical only), 3V Tier: F (0.35 m) Class: IX (0.02 m, 1x10-4m/m) Class evaluation radius: 0.3 km (urban), 1 km (rural) |
| Mark characteristics | Campaign GNSS Conventional observations Precise levelling |
| Location | Sited so that surveyors can easily and safely locate and occupy Suitable for collecting GNSS observations |
| Mark Access | Physical access to marks to collect GNSS observations Visible from afar to enable conventional observations |