Surveyor with a level measuring heights

Navigating elevation data in Auckland requires knowing which vertical reference system your plans use. Auckland Level Datum 1946 (AUCK1946) and New Zealand Vertical Datum 2016 (NZVD2016) are the two primary systems you will encounter across site plans, drainage as-built plans, and council records.

Understanding the Two Datums

Feature AUCK1946 (Auckland Level Datum 1946) NZVD2016 (NZ Vertical Datum 2016)
Basis Local Mean Sea Level recorded at Auckland Harbour tide gauges in 1946 Modern nationwide gravity derived model (NZGeoid2016)
Coverage Auckland regional area only Unified nationwide standard
Status Historical regional standard; legacy system Official nationwide height datum adopted by Auckland Council on 1 July 2024
Key Advantage Simple historical benchmark network Highly accurate, seamlessly links with GPS/GNSS, immune to sea-level shifts

The Elevation Offset

Across the Auckland region, NZVD2016 heights are lower than AUCK1946 heights by approximately 250 mm to 360 mm. Because early physical levelling accumulated minor distortions across long distances, the shift is not a single flat number—it varies based on your precise location.

To convert between the two systems, you need to apply the site-specific offset:

  • Converting to NZVD2016: NZVD2016 = AUCK1946 – Offset
  • Converting to AUCK1946: AUCK1946 = NZVD2016 + Offset

Example: A benchmark recorded at 10.000 m in AUCK1946 with a local offset of 0.288 m becomes 9.712 m in NZVD2016.

Methods for Converting Site Heights

  • LINZ Data Service (GIS & CAD): Use Toitū Te Whenua LINZ’s online transformation software or upload the official grid file (AUCK46-NZVD2016) into your spatial tools for automatic coordinate-based conversion.
  • Dual-Datum Benchmarks: For small localised sites, reference nearby survey marks that publish official elevations in both datums to derive your local offset.

Contact us to ensure your levels are in the right datum.

Surveyor’s Warning:

Always check the title block on site plans, flood hazard maps, and drainage diagrams. A 300 mm datum mix-up can cause gravity-fed stormwater pipes to slope backwards or result in non-compliant finished floor levels (FFL) relative to floodplains. Council no longer accepts anything other than NZVD2016 going forward.