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Horizontal distortion grids

The most accurate method for transforming coordinates between New Zealand Geodetic Datum 1949 (NZGD1949) and New Zealand Geodetic Datum 2000 (NZGD2000) is to use a distortion grid. On this page you can download the distortion grid file and find other information available regarding this horizontal grid transformation.

Unlike the simple 3- and 7-parameter transformations which are used for many coordinate transformations (see Understanding coordinate conversions, the transformation between New Zealand Geodetic Datum 1949 (NZGD1949) and New Zealand Geodetic Datum 2000 (NZGD2000) requires a distortion grid. This is because distortions, such as deformation, have occurred within the datum. 

Understanding coordinate conversions

More information about the distortion grid can be found on NZGD1949 - NZGD2000 Distortion Grid.

 

Conditions of use

Downloading or using any of our geodetic software applications is taken to be acceptance of the conditions for geodetic downloads listed on the Geodetic software and downloads page

NZGD1949 and NZGD2000 distortion grid

An ASCII version of the distortion grid can be downloaded as a zip file:

Last updated 14 August 2024

Related information:

LINZS25000 - Standard for New Zealand Geodetic Datum 2000

LINZG25700 Fact sheet - a summary of the key information in LINZS25000

Online coordinate converter

NZGD2000 - NZGD1949 source code on the geodetic software page

NZGD2000 - NZGD1949 source code

This programme provides a conversion between New Zealand Geodetic Datum 2000 (NZGD2000) and New Zealand Geodetic Datum 1949 (NZGD1949) using the NTv2 ASCII distortion grid file. The source code is provided in the C programming language.

Last updated 4 February 2014

To incorporate this source code into custom software, you must use the two files from the zip folder (linzgrid.c and linzgrid.h) and the ASCII version of the distortion grid. More information can be found in the comments of the linzgrid.c file.