[Proj] proj-4.6.0 and BETA2007.gsb

Frank Warmerdam warmerdam at pobox.com
Mon Jan 21 10:58:17 EST 2008

Oliver Eichler wrote:
> The projection string I use is:
> "+proj=tmerc +lat_0=0 +lon_0=12 +k=1.000000 +x_0=4500000 +y_0=0
> +ellps=bessel +datum=potsdam +units=m +no_defs  +nadgrids=./BETA2007.gsb"


I think your problem is the coordinate system definition.  It includes
+datum=potsdam and +nadgrids. These will conflict and it isn't necessarily
clear whether PROJ.4 will use the +towgs84 definition expanded from the
+datum, or will use the +nadgrids values.  I'd guess the potsdam datum
was unknown (and so unexpanded) in the older version and now it does get
expanded and the towgs84 used instead of the nadgrids statement.  Instead
try using:

+proj=tmerc +lat_0=0 +lon_0=12 +k=1.000000 +x_0=4500000 +y_0=0
   +ellps=bessel +units=m +no_defs  +nadgrids=./BETA2007.gsb

Best regards,
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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