[Proj] Coordinate transformation assistance
Frank Warmerdam
warmerdam at pobox.com
Thu Apr 12 08:31:14 PDT 2007
Bjørn Krangnes wrote:
> Hi,
>
> I am trying to go from Irish Transverse Mercator to IrishGrid75 Ireland
> using GDAL C# and EPSG codes.
>
> The code is like this:
>
>
> double[] xyz = new double[3];
>
> OGR.SpatialReference inp = new OGR.SpatialReference(null);
> OGR.SpatialReference outp = new OGR.SpatialReference(null);
>
>
> int stat1 = inp.ImportFromEPSG(2157); // Irish Transverse
> Mercator
> int stat2 = outp.ImportFromEPSG(29903); // IrishGrid75 Ireland
>
> OGR.CoordinateTransformation tra = new
> OGR.CoordinateTransformation(inp, outp);
>
> xyz[0] = 600000.0;
> xyz[1] = 700000.0;
> xyz[2] = 22.22;
>
> tra.TransformPoint(xyz);
>
> I think the problems is with ImportFromEPSG because both istat1 and istat2
> is 6 after execution. How to initialize the EPSG codes ?
>
> I am resending this request beacuse I have not had any feedback on my
> previous request.
Bjørn,
You don't indicate what the transformed result is or why you think there
is an error. But if ImportFromEPSG() is failing (result 6 is
OGRERR_FAILURE) then it is likely because the EPSG .csv files aren't
being found. One way around this is to set the GDAL_DATA environment
variable to point to the directory where the files like pcs.csv and gcs.csv
live. In the source distribution they are in the gdal\data directory.
I think you can also do something like:
Gdal.PushFinderLocation("C:\\gdal\\data");
or
Gdal.SetConfigOption( "GDAL_DATA", "C:\\gdal\\data" );
though my csharp-gdal-fu is weak.
Best regards,
--
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I set the clouds in motion - turn up | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush | President OSGeo, http://osgeo.org
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