Meridional circuits

There are 28 meridional circuits (9 in the North Island and 19 in the South Island) which make up the set of survey regions used in New Zealand. The term "meridional" refers to the fact that these circuits are run in a north-south direction, aligned with “meridians” of longitude. A map showing the locations of each of the 28 meridional circuits is provided below. These boundaries are also available through the LINZ Data Service:

NZ Meridional Circuit Boundaries (NZGD2000)

Each meridional circuit is its own projection. A projection is used to convert points on a 3-dimensional curved surface of the Earth onto a 2-dimensional flat surface. Unlike geodetic datums, which are used to maintain coordinate accuracy, projections deliberately distort the data so that these can be shown on paper or screens.

The original meridional circuits were established in 1877 to support the implementation of cadastral surveying in New Zealand. The horizontal coordinates in the original meridional circuits used a “plane” coordinate systems with no formal mathematical projection to account for the curvature of the Earth. In 1949 these circuits were upgraded to transverse Mercator projections, a cylinder-shaped projection that is suited for depicting areas, like New Zealand, which extend in a north-south direction. These were referred to as “Circuit 1949” to distinguish them from both the original circuits.

The current meridional circuits are also transverse Mercator projections, but they are now based on New Zealand Geodetic Datum 2000 (NZGD2000) and the origin of each circuit no longer relates to a physical mark. These latest circuits are referred to as “Circuit 2000”.

New Zealand Geodetic Datum 2000 (NZGD2000)

While New Zealand Transverse Mercator 2000 (NZTM2000) is used for official topographic mapping purposes in mainland New Zealand, cadastral surveys are conducted in terms of the local meridional circuit. Learn more about Cadastral Survey Rules implementation, or access the Cadastral Survey Rules 2021 on the New Zealand legislation website:

• Cadastral Survey Rules implementation
• Cadastral Survey Rules 2021

The meridional circuits are defined in the LINZ standard LINZS25002:

Standard for New Zealand Geodetic Datum 2000 Projections