AW: [gdal-dev] Re: ogr2ogr BeTA2007 grid

[Tilo Villwock]

Hey that did the trick. Seems like with EPSG codes the nadgrids parameter is just being dropped without further notice. So it's necessary to use the complete proj parameters for both shape files including the nadgrids and wktext option to get the results right. With PROJ_DEGUB=1 I also noticed that it is indeed necessary to put "./" before the grid file name, as it otherwise looks for it in the working directory of fwtools. Anyways, cs2cs as well as ogr2ogr work now as expected!

Despite that, it seems like the wheregroup.com tutorial (http://wheregroup.com/de/system/files/Transformation_mit_freien_Tools_Praxis.pdf) wasn't right after all and from what I discovered, it makes me wonder whether they tested their results at all or just copied from someone else.

Thanks a lot anyways!

-------- Original-Nachricht --------
> Datum: Wed, 14 Apr 2010 13:33:58 +0200
> Von: "Schmitz, Uwe" <uwe.schmitz at bezreg-koeln.nrw.de>
> An: "Tilo Villwock" <tilovillwock at gmx.de>, gdal-dev at lists.osgeo.org
> Betreff: AW: [gdal-dev] Re: ogr2ogr BeTA2007 grid

> Tilo,
> 
> > > 
> > > ogr2ogr -s_srs "+proj=tmerc +lat_0=0 +lon_0=9 +k=1 +y_0=0 
> > +ellps=bessel 
> > > +nadgrids=BETA2007.gsb" -t_srs EPSG:25832 target.shp source.shp
> > 
> > I used the parameters instead, but it didn't work either. In 
> > fact, I think it doesn't matter since ogr2ogr looks up the 
> > same parameters in its EPSG file and converts the whole 
> > string to WKT anyway. So the result should be the same.
> > 
> > Any other thoughts?
> 
> please try to verify that the grid is read. 
> Therefore set the environment variable
> PROJ_DEBUG before running ogr2org, e.g. (Windows cmd):
> 
> set PROJ_DEBUG=1
> 
> Then you see if the grid is accessed at all.
> 
> FYI, here is my setup for transforming coordinates
> with cs2cs from german "Gauss-Krueger stripe 3/DHDN" to 
> "UTM Zone 32N/ETRS89"):
> 
> cs2cs \
>       +proj=tmerc \
>       +lat_0=0 \
>       +lon_0=9 \
>       +k=1.0 \
>       +x_0=3500000 \
>       +y_0=0 \
>       +ellps=bessel \
>       +units=m \
>       +nadgrids=BETA2007.gsb \
>    +to \
>       +proj=utm \
>       +ellps=GRS80 \
>       +towgs84=0,0,0 \
>       +zone=32
> 
> Hope that helps.
> Uwe

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