Transformation from WGS84 to NZTM2000

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01-20-2013 03:55 PM
HanliePretorius
New Contributor III
Hi,

I'm working in ArcGIS 10.0.

I have a JPG image georeferenced in WGS84.

When I try to reproject this to NZTM2000 using the Project Raster tool, I can select the source and destiniation coordinate systems, but there is no transformation that is appropriate (only the reverse one exists in ArcGIS) and, although transformation is 'optional', an error message appears that it's needed when I try to reporoject without specifying a transformation.

I have two problems:

1. ArcGIS doesn't have a built-in transformation between WGS84 and NZTM2000. It only has the reverse - NZTM2000 to WGS84.

2. I don't know how to enter parameters for a custom transformation. The only detailed transformation information on NZTM2000 I could find, is on this page:
http://www.linz.govt.nz/geodetic/conversion-coordinates/projection-conversions/transverse-mercator-p...
But I don't know how to udse this information in parameters for one of ArcGIS's transformation methods.

I would be grateful for any help.

Regards
Hanlie
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4 Replies
WadeLobb
Occasional Contributor
It works both ways.

So even though it says NSGD_2000_To_WGS_1984_1 just use it and it will work to convert 1984 to NZTM200

I don't know much about coordinate systems but I think NZTM is basically a projection of WGS_1984 so the data dosn't move but it will be put  in the right coordinate system for you maps

See http://www.linz.govt.nz/geodetic/datums-projections-heights/geodetic-datums/world-geodetic-system-19... "For most practical purposes the WGS84 geodetic datum is coincident with the NZGD2000 and RSRGD2000 geodetic datums. Therefore coordinates in these systems can normally be assumed to be coincident."
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HanliePretorius
New Contributor III
Thanks for the reply.

I had tried the conversion the other way around, but I ended up with a garbage image.

The reason was not the transformation, though, it was that I hadn't completed the georeferencing properly.
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BruceHarold
Esri Regular Contributor
Hi

NZTM uses GRS80 datum, the XYZ transformation between that and WGS84 is 0,0,0, so null.
There must be some other issue here, maybe a support call is in order.

Regards
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HanliePretorius
New Contributor III
Sorry, I think I wasn't clear in my previous post. The transformation between datums and the projection onto Transverse Mercator worked properly once I saved the georeferenced image properly.

So I think everything is in order.
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