[Qgis-developer] Difference for transform reference system between QGIS and GDAL
motta.luiz at gmail.com
Fri Jan 17 11:43:13 PST 2014
Thank Jürgen for your explanation about how QGIS set the reference system
I agreement with André Joost about the user should select your specific
The source of my problem is the creating of shapefile by GDAL/OGR.
For creating shapefile, the OGR/GDAL not using all parameters of reference
I resolve my problem, creating the GML file, in this case, the refefence
system is identical of source.
How suggested Etienne i will raise this issue in gdal-dev list.
If someone want to see the script example:
2014/1/17 Andre Joost <andre+joost at nurfuerspam.de>
> Am 17.01.2014 11:56, schrieb Luiz Motta:
> The question is exact this, why the QGIS read the PRJ and understands the
>> 'towgs84', otherwise, the GDAL don't understands, where , the QGIS use the
>> GDAL/OGR provider ?
> This is an intended behaviour.
> Other software (like ESRI) don't write datum shifts in the .prj file, but
> leave it to the end user to select one of the available shifts. QGIS has to
> handle these files correctly, so it looks up the EPSG table and selects the
> best fitting code. If you think it has guessed wrong, you can assign
> another CRS to the layer.
> GDAL does no guessing. Unless there are not datum shifts provided on
> source and target CRS (using either +datum, +towgs84 or +nadgrids), it does
> no datum shift at all. You can specify -s_srs to override the source file's
> .prj file with an EPSG code that contains a datum shift. This should bring
> the same result as QGIS does automatically.
> André Joost
> Qgis-developer mailing list
> Qgis-developer at lists.osgeo.org
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