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 page 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