Coordinates can be converted between datums and projections automatically using this online utility using one of two interfaces.
Readmore about time dependent coordinate transformation.
Basic online conversion
This interface allows conversions between pre-selected datums and projections using default input and output parameters. This is the simplest way to convert coordinates on the LINZ website.
Use the basic online conversion tool
Detailed online conversion
This interface enables users to choose from a wider range of datums, projections and height systems. It also allows a variety of input and output formats (including bulk options) that are more suited to users with an understanding of coordinate and height conversions.
Use the advanced online conversion tool
About these datums and projections
The online coordinate conversion tool has been updated to correctly convert between New Zealand coordinate systems and global coordinate systems such as the International Reference Frame (ITRF) and World Geodetic System (WGS84) global datums and to provide better support for vertical datum transformations. The update also includes the new New Zealand Vertical Datum 2016. The following sections list the main impacts of these changes.
Date required for some transformations
Some transformations now require specifying a date at which the transformation applies. This is because New Zealand is moving across the earth at about 5cm per year due to plate tectonics. The New Zealand coordinate systems such as NZGD2000 and NZTM are moving with it, whereas the global coordinate systems such as the WGS84 and ITRF realisations are not. The relationship between them changes over time and so to convert between them requires knowing the date at which the conversion is to apply.
Generally the date will be that at which the coordinates were measured. For lower accuracy requirements using the correct date is not critical. Generally the relationship only changes at around 5cm per year. More significant changes happen when coordinates are affected by earthquakes.
Dates can be entered in a number of formats, such as a decimal year (2016.5) and day month year (25 June 2016). Alternatively the word “now” can be used to apply the transformation for the current date.
Many transformations do not require a date (for example from NZGD2000 to NZTM), and for these the date can be left blank.
Multiple versions of WGS84
The previous version of the online conversion defined a WGS84 coordinate system that was identical to NZGD2000. In fact there are multiple realisations of WGS84 and so converting accurately between WGS84 and other datums requires knowing what version of WGS84 applies. Also in many cases coordinates are labelled as WGS84 when they are actually in terms of other datums, such as ITRF2008 or NZGD2000.
You can get the same results as the previous coordinate converter by using NZGD2000 as the coordinate system instead of WGS84.
Vertical datum transformations
The new version of the converter provides a new form to simplify converting between New Zealand vertical datums. It also includes the new vertical datum NZVD2016, as well as grid based transformations between NZVD2016 and the local sea level datums.
Coordinate entry form
Coordinates in the previous converter were entered by default into separate boxes for each coordinate. This has been removed and instead coordinates are entered by default into a free format text box.
Accessing the previous version of the converter
The previous version of the online coordinate conversion tool will be available until the end of 2016.