nztm2000-latlng

Convert values between NZTM2000 and latitude/longitude. The implementation is a direct translation of the C source code found on this LINZ website. The precision of this module is also comparable to that of the origional C implementation.

The original C files can be found in the "original" folder of this GIT repository.

1. Methods

1.1 tm_geod

Routine to convert from New Zeland Tranverse Mercator (NZTM2000) to latitude and longitude. Six decimal point places are kept for the converted latititude and langitude.

Parameters

tm_geod(easting, northing); // easting and northig are in meters;

Return

{
  "easting": 1783295, // in meters, whole number
  "northing": 5868193, // in meters, whole number
  "latitude": -37.314852, // in degree, six decimal places
  "longitude": 175.068489 // in degree, six decimal places
}

1.2 geod_tm

Routine to convert from latitude and longitude to New Zeland Tranverse Mercator (NZTM2000). The converted easting and northing are whole numbers.

Parameters

geod_tm(latitude, longitude); // latitude and longitue are in degrees

Return

{
  "easting": 1783295, // in meters, whole number
  "northing": 5868193, // in meters, whole number
  "latitude": -37.314852, // in degree, six decimal places
  "longitude": 175.068489 // in degree, six decimal places
}

2. Test

The module replicated the C testing code as well by the following npm script.

npm run test

The conversion can be checked by the LINZ online converter.

3. Run C implementation

Please install gcc or any C compiler on the development host machine.

Complie the C implementation:

cd original
gcc -o nztm nztm.c

Run the code:

echo "1783295.000  5868193.000" | ./nztm