Hi all, Thank Jürgen for your explanation about how QGIS set the reference system from source.
I agreement with André Joost about the user should select your specific reference. 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 system. 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: http://pastebin.com/PbjwdrHR Regards, Luiz Motta 2014/1/17 Andre Joost <[email protected]> > 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. > > > HTH, > André Joost > _______________________________________________ > Qgis-developer mailing list > [email protected] > http://lists.osgeo.org/mailman/listinfo/qgis-developer > -- Luiz Motta Analista Ambiental - IBAMA/COTIG Instituto Brasileiro do Meio Ambiente dos Recursos Naturais - IBAMA IBAMA - SCEN Trecho 2 - Ed. Sede - Cx. Postal nº 09566 CEP 70818-900 - Brasília-DF Tel: 61.3316-1807 Skype: ibama_luiz-motta
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