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<DIV>Hi Brendan,</DIV>
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<DIV>First make sure you have the NZGD49 <=> NZGD2000 datum distortion grid installed into your proj4 lib directory. </DIV>
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<DIV>You can download the grid from the:</DIV>
<DIV> LINZ website <A href="http://www.linz.govt.nz/core/surveysystem/geodeticinfo/geodeticdatums/nzgd49tonzgd2000/index.html">http://www.linz.govt.nz/core/surveysystem/geodeticinfo/geodeticdatums/nzgd49tonzgd2000/index.html</A> or</DIV>
<DIV> PROJ.4 ftp <A href="ftp://ftp.remotesensing.org/proj/proj-datumgrid-1.3.zip">ftp://ftp.remotesensing.org/proj/proj-datumgrid-1.3.zip</A></DIV>
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<DIV>The PROJ.4 lib directory is either ms4w\proj\nad for MS4W, proj_lib for FWTools, or can be manually set using the PROJ_LIB environment variable.</DIV>
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<DIV>I would change your command a little so you don't need to specify the NZTM proj def on the command line. Instead I would obtain it from the 'epsg' coordinate definition file in the proj lib directory :)</DIV>
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<DIV>ogr2ogr -f "ESRI Shapefile" output.shp input.shp -s_srs "+proj=nzmg +lat_0=-41 +lon_0=173 +x_0=2510000 +y_0=6023150 +ellps=intl +datum=nzgd49 +units=m +nadgrids=nzgd2kgrid0005.1gsb +wktext" -t_srs EPSG:2193</DIV>
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<DIV>Note the use of the "+wktext" parameter for the NZMG proj text. You need at least OGR 1.4.0 for this to work. See <A href="http://lists.maptools.org/pipermail/gdal-dev/2007-April/012561.html">http://lists.maptools.org/pipermail/gdal-dev/2007-April/012561.html</A> for more info.</DIV>
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<DIV>Cheers</DIV>
<DIV>Jeremy<BR><BR>>>> <bcervin@gmail.com> 20/04/2007 11:49 >>><BR></DIV>
<DIV style="COLOR: #000000">Hello Jeremy,<BR><BR>I stumbled across your discussion about nad grid and ogr2ogr. I'm trying to do the same reprojection as you.<BR><BR>As I noticed that this was very recent I'm hoping you might be able to give me some help.<BR><BR>I'm having difficulty with ogr2ogr, NZMG->NZTM conversion for shape files.<BR><BR>I've got what i think should work but it simply isn't. This is my command:<BR>ogr2ogr output.shp input.shp -t_srs '+proj=tmerc +lat_0=0.0000000000 +lon_0=173.0000000000 +k_0=0.9996000000 +x_0=1600000.0000000000 +y_0=10000000.0000000000 +a=6378137 +rf=298.257222101 +no_defs +towgs84=0.000,0.000,0.000' -s_srs '+proj=nzmg +lat_0=-41.0000000000 +lon_0=173.0000000000 +x_0=2510000.0000000000 +y_0=6023150.0000000000 +a=6378388 +rf=297 +no_defs +nadgrids=nzgd2kgrid0005.gsb'<BR><BR>I suspect that your command would work perfectly for me. I'm using a MS4W version of ogr2ogr.<BR><BR>Thanks for your time.<BR><BR>Cheers, Brendan.<BR></DIV>
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<DIV><STRONG>Thank you.</STRONG> <BR></DIV>
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