[gdal-dev] Odd things after using ogr2ogr

[Frank Warmerdam]

Kai Behncke wrote:
> then the weird thing start. I Load "selektion_roads_4326" in Quantum GIS (under the 4326-projection)
> and after that "selektion_roads_31467" (here I use on the fly the 4326-projection)
> but the layer don`t lay over each other, there is a mismatch of about 50 meter.
> 
> See her:
> http://www.selbstverwaltung-bundesweit.de/test/mystery.PNG
> 
> How can this be?  Might this be a bug in reprojection?

Kai,

I imagine there is an issue with how the datum shifting is being done.
It looks to me that by default EPSG:31467 does not have datum shift
parameters supplied with it (as expected by GDAL/OGR).

Is it possible that your qgis uses PROJ.4.4.9 and your ogr2ogr uses
4.5.0?  (or the other way around)?

If so, the default rules for shifting between ellipsoids without stated
datum parameters will be different.

Even if they are the same version, I would suspect that one way there
are proper datum shift parameters being used, and the other way there
are not.

Best regards,
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