Using your GPS unit with Topo50 data

Learn how to coordinate your GPS with Topo50 data.

It is important that your GPS unit fits with the new datum and projection to ensure consistency with the emergency services and defence agencies. These agencies now use NZTM2000 and the Topo50 maps for their emergency and base mapping.

Setting the new datum (NZGD2000)

If you’re using a current GPS systems, simply change the settings on the GPS receiver to NZGD2000, the datum used by Topo50 to determine latitude and longitude.

If your GPS doesn’t support NZGD2000, it can still support Topo50. Set your GPS receiver to the default datum setting of World Geodetic System 1984 (WGS84). Practically, WGS84 is the same as NZGD2000. Your GPS receiver’s latitudes and longitudes will be compatible with Topo50 maps.

Setting the new projection (NZTM2000)

To get Topo50 grid coordinates (northings and eastings) on your GPS check that it  supports the projection used for Top50 maps, NZTM2000. Either select the appropriate menu option in your GPS unit or check the specifications in the user manual.

If your GPS doesn’t support NZTM2000, you may be able to input a user-defined projection. Check the user manual on how to access this feature.

These are the NZTM2000 parameters you need to input: 

ProjectionTransverse Mercator
Origin Latitude0.0 degrees South
Origin Longitude173.0 degrees East
False Northing10,000,000 m North
False Easting1,600,000 m East
Central Meridian scale factor0.9996
Last Updated: 1 December 2015