2016-04-24 17:58 GMT+02:00 Even Rouault <[email protected]>: > I guess we would want to improve the shapefile importer to get the WKT > definition from the GDAL EPSG DB when a AUTHORITY EPSG node is found. Could > you > create a ticket about that ?
Done: https://trac.osgeo.org/gdal/ticket/6485 :Stefan 2016-04-24 17:58 GMT+02:00 Even Rouault <[email protected]>: > Le dimanche 24 avril 2016 17:46:45, Stefan Keller a écrit : >> 2016-04-24 17:34 GMT+02:00 Even Rouault <[email protected]>: >> > Could you post the .prj file ? >> >> Bien sur: I posted both CRS. >> Hope attachments come through. > > OK, that explains it. > > The .prj file are somewhere between a old-style ESRI WKT and regular OGC WKT, > in that they have a AUTHORITY EPSG node, but no TOWGS84 node. > Hence when you do the direct conversion, no datum shift is taken into account. > When you do the 2-step conversion, in the first step, the GPKG driver has a > logic to add entries in its gpkg_spatial_ref_sys table based on the source > SRS. When the source SRS has a EPSG node, the WKT definition is read from the > GDAL SRS db from the EPSG code (thus ignoring the rest of the WKT), which > brings back the default TOWGS84. The second ogr2ogr call then applies it when > reprojecting. > > I guess we would want to improve the shapefile importer to get the WKT > definition from the GDAL EPSG DB when a AUTHORITY EPSG node is found. Could > you > create a ticket about that ? > > Even > >> >> :Stefan >> >> 2016-04-24 17:34 GMT+02:00 Even Rouault <[email protected]>: >> > Le dimanche 24 avril 2016 17:29:36, Stefan Keller a écrit : >> >> Given a Shapefile "swiss_admin_boundaries.shp" in EPSG:2056 (or 21781, >> >> to be downloaded for free at [1]) I have problems transforming it to >> >> any other SRS/CRS. >> > >> > Could you post the .prj file ? >> > >> >> When doing this: >> >> > ogr2ogr -f "GPKG" swiss_admin_boundaries1.gpkg >> >> > swiss_admin_boundaries.shp -t_srs EPSG:3857 >> >> >> >> ... swiss_admin_boundaries2.gpkg have a shift of about 150m. >> >> >> >> But when I convert Shapefile first e.g. to GeoPackage, and transform then: >> >> > ogr2ogr -f "GPKG" tmp.gpkg swiss_admin_boundaries.shp >> >> > ogr2ogr -f "GPKG" swiss_admin_boundaries2.gpkg tmp.gpkg -t_srs >> >> > EPSG:3857 del tmp.gpkg >> >> >> >> ... swiss_admin_boundaries2.gpkg is correct! >> >> >> >> What could be the reason? >> >> >> >> :Stefan >> >> >> >> [1] https://opendata.swiss/en/dataset/swissboundaries3d-gemeindegrenzen >> >> _______________________________________________ >> >> gdal-dev mailing list >> >> [email protected] >> >> http://lists.osgeo.org/mailman/listinfo/gdal-dev >> > >> > -- >> > Spatialys - Geospatial professional services >> > http://www.spatialys.com > > -- > Spatialys - Geospatial professional services > http://www.spatialys.com _______________________________________________ gdal-dev mailing list [email protected] http://lists.osgeo.org/mailman/listinfo/gdal-dev
