Hi, Only now, based on Even's answer, I was able to find the proper documentation. My fault! I was searching using uppercase and git grep "_OGR_GEOMETRY_" was returning nothing.
Just an update regarding the documentation: 1) OGR_GEOMETRY is well documented at https://gdal.org/user/ogr_sql_dialect.html#ogr-geometry 2) "_OGR_GEOMETRY_" is also pretty well documented in the same document, at https://gdal.org/user/ogr_sql_dialect.html#geometry-field 3) As an alternative for all drivers, GEOMETRY field, used in SQL SQLite dialect, is well documented at https://gdal.org/user/sql_sqlite_dialect.html#geometry-field Regards, Jorge Às 22:36 de 19/11/20, Jorge Gustavo Rocha escreveu: > Hi Even, > > Thanks for the feedback. The difference you mentioned is well understood > with the example: > > -sql 'select OGR_GEOMETRY, "_OGR_GEOMETRY_" from layer' > > I get exactly what is expected from both fields: > > POLYGON | POLYGON(...) > POLYGON | POLYGON(...) > > It would be nice to allow "_OGR_GEOMETRY_" in ogr2ogr -select, but the > usage of -sql works. > > To make the usage of this "_OGR_GEOMETRY_" more clear, may I add an > example to https://gdal.org/programs/ogrinfo.html? > > I think this is not well documented. The only reference I used [1] is > not accurate anymore. It says: > > "the special field names “OGR_GEOMETRY” and “OGR_STYLE” will be > interpreted to refer to the geometry and style values of a feature". > > Regards, > > Jorge > > [1] > https://gdal.org/development/rfc/rfc29_desired_fields.html?highlight=ogr_geometry > > > Às 18:27 de 19/11/20, Even Rouault escreveu: >> Jorge, >> >>> To get only the geometry column from a shapefile, I can do: >>> >>> ogrinfo cidade.shp -sql "select OGR_GEOMETRY from cidade" >> >> This is a bit a misnomer: OGR_GEOMETRY is a special keyword to get the >> geometry *type* of a geometry ("POLYGON", "POINT", "LINESTRING"), not the >> geometry itself. For that, for format such as shapefile which don't have a >> named geometry column, you must use the "_OGR_GEOMETRY_" (quoted with double >> quotes as starting with underscore) >> >>> But this column name is not allowed in the -select option on ogr2ogr: >>> >>> ogr2ogr -overwrite -skipfailures -update PG:service=estarreja cidade.shp >>> -select OGR_GEOMETRY >> >> you can use -sql here as well >> >> Could perhaps make sense to support the special "_ogr_geometry_" field here >> too >> >> Even >> > -- OSGeo Portugal NIF: 509588190 email: [email protected] https://www.osgeopt.pt/ Próximo evento: SASIG 2017, 20 a 22 de novembro, Porto Mais informações: http://osgeopt.pt/sasig2017/ _______________________________________________ gdal-dev mailing list [email protected] https://lists.osgeo.org/mailman/listinfo/gdal-dev
