<div class="gmail_quote"><div bgcolor="#ffffff" text="#000000">I have implemented a Proj4js transformation for New Zealand Map Grid (NZMG) co-ordinates (EPSG:27200). <a href="http://spatial-reference.org">spatial-reference.org</a> gives a description of the transformation, but the '+proj=nzmg' was not available in the current version in the repository. This projection is not related to any of the existing types, so I implemented it.<br>
<br>I would like to contribute this code to Proj4js. However, it is not obvious how to submit this code to the project. Can anyone here point me to the right place?<br><br>Stephen Irons<br><br><br>Background<br><br>New Zealand Map Grid (NZMG) is a projection used to convert latitude
and longitude to easting and northing coordinates in metres. It was
designed to minimize the scale error over the land area of New Zealand
and cannot be used elsewhere.<br>
<br>The New Zealand govnernment survey agency, LINZ (Land Information New Zealand) has published two series of maps covering
the mainland areas of New Zealand.<br>
<ul>
<li>262-series is 1:250000</li>
<li>260-series is 1:50000</li>
</ul>
These maps are available in printed form and are currently the only
large-scale maps of New Zealand widely available to the general public. Vector data is also available.<br><br>Various commercial concerns have scanned these maps, or generated tiles from the vector data, and released products using these tiles. I have one of these products and want to use the tiles with OpenLayers.<br>
<br>New Zealand Map Grid<br><br>New Zealand Map Grid was designed by Dr W. I. Reilly in 1973. Its
official specification is published as <i>New Zealand Map Grid</i>,
Department of Lands and Survey Technical Circular 1973/32. A scanned
image of the publication is available at
<a href="http://www.linz.govt.nz/docs/miscellaneous/nz-map-definition.pdf" target="_blank">http://www.linz.govt.nz/docs/miscellaneous/nz-map-definition.pdf</a><br>
<br>
It is also described in <i>Conversion between Latitude and Longitude
and New Zealand Map Grid</i>, OSG Technical Report 4.1, 1998. This
document is available at
<a href="http://www.linz.govt.nz/docs/miscellaneous/nzmg.pdf" target="_blank">http://www.linz.govt.nz/docs/miscellaneous/nzmg.pdf</a><br>
<br>
NZMG is given EPSG code EPSG:27200. It is defined at
<a href="http://spatialreference.org/ref/epsg/27200/proj4/" target="_blank">http://spatialreference.org/ref/epsg/27200/proj4/</a>
as<br>
<ul>
<li><tt>"+proj=nzmg +lat_0=-41 +lon_0=173 +x_0=2510000 +y_0=6023150
+ellps=intl +datum=nzgd49 +units=m +no_defs"</tt></li>
</ul>
Now, most of this is known to Proj4js code. However, the projections
'nzmg' is not know, and needs to be implemented.<br><br></div></div><br>