Do you need a surveyor or a farm mapper?

What only a surveyor can do

Deciding where a legal boundary is counts as a cadastral survey. Under the Cadastral Survey Act 2002 that work has to be done by, or under the direction of, a licensed cadastral surveyor. Section 57 makes it an offence for anyone else. Toitū Te Whenua LINZ’s guidance goes further: someone who isn’t licensed should never put in a mark that anyone, including a neighbour, could take to be a boundary mark.

You need a licensed cadastral surveyor if you are:

• In a disagreement with a neighbour about where the boundary is
• Subdividing, adjusting a boundary or creating a new title
• Pegging the boundary before building a fence or structure on or near it
• Registering an easement, such as a right of way or a water pipe across a neighbour’s land

The Cadastral Surveyors Licensing Board keeps a public register, so you can check that a surveyor is licensed.

What a farm map is for

A farm map records the farm as it is run: fences, paddocks, races, water and planting, with an area for each. It’s drawn from aerial imagery and corrected by the person who knows the farm. That is what you need to:

• Work out paddock areas for fertiliser, feed budgets and stocking rates
• Show staff, contractors, your bank or a consultant how the farm is laid out
• Start a farm plan or environmental plan
• Show buyers the layout when you sell

A farm map does not decide where the legal boundary is, and anyone selling you one should say so plainly.

Why title lines on online maps can be well out

Property boundaries shown on online maps usually come from the LINZ digital cadastre. LINZ says the accuracy of about 30% of it, mostly in rural areas, is largely unchanged from the original record maps. Some of those maps were drawn at 1:50,000, where a 1 mm error on paper is 50 m on the ground.

LINZ’s own accuracy targets, at 95% confidence:

So a title line drawn over aerial photos can cut through a neighbour’s paddock or miss your fence by a wide margin, and neither the fence nor the title is necessarily wrong. The line on the screen just isn’t precise enough to tell. It’s one reason a farm map should follow the fences rather than the title diagram when it works out areas. See gross vs effective area.

Which do you need?

When a map shows something worth surveying

Mapping the fences sometimes shows a big gap between what’s fenced and the title. We can show that gap as a title vs fenceline comparison in Baseline Plus: both lines overlaid, with the difference shaded and given in hectares. It compares two datasets. It isn’t evidence of ownership or encroachment. If the gap matters to you, that’s the point to call a licensed surveyor, and we’ll tell you so.

Sources

• Toitū Te Whenua LINZ, Accuracy of the digital cadastre
• Toitū Te Whenua LINZ, Restrictions on unlicensed surveyors undertaking redefinition surveys
• Cadastral Survey Act 2002, New Zealand Legislation
• Cadastral Surveyors Licensing Board, search for a licensed surveyor