Am 07.03.18 um 11:50 schrieb Michael Schulz:
Dear devs,

why is og2ogr using a grid shift file explicitely specified in the
proj4 string in the s_srs parameter and not when the same proj4 string is
in the system-wide proj4/epsg file?

This example gives correct projected results:

ogr2ogr -f 'ESRI Shapefile' target.shp -s_srs "+proj=tmerc +lat_0=0
+lon_0=9 +k=1 +x_0=3500000 +y_0=0 +ellps=bessel
+nadgrids=@BWTA2017.gsb,BETA2007.gsb +units=m +wktext" -t_srs "EPSG:25832"

The proj4/epsg contains exactly the same definition for EPSG:31467, but
when used like this:

ogr2ogr -f 'ESRI Shapefile' target.shp -s_srs "EPSG:31467" -t_srs
"EPSG:25832" source.shp

the transformation is using the towgs84 parameters defined in

Is this the intended behaviour?

Yes, this is intended. GDAL has its own CRS definition files, and does normally not fall back to the proj4 folder definitions.

C:\OSGeo4W64\share\gdal\datum_shift.csv is the file to look for, containg a definition for EPSG:4314 DHDN, which will be used for all DHDN based projected CRS.

So try to adjust that file.

Andre Joost

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