Hi David, the sql script that have used in DB Manager and has produced one of the results listed in the table is the following one:
SELECT AsEWKT ( ST_Transform( MakePoint( 541000 , 4516000 , 23033 ) , 25833 )); As you can see I am not using any grid file to increase the precision of the transformation, so I expected the same results of the "export layer" method. There should be something in the way the Prog lib is called by QGIS in the two different contexts. I hope this helps to better understand the question. Antonio Il giorno sab 21 feb 2026 alle ore 16:43 Antonio Valanzano < [email protected]> ha scritto: > I have tried to transform the coordinates of a single point (541000, > 4516000) with epsg:23033 into 2 other coordinate systems (epsg:25833 e > 6708). > > I have done these transformations using 2 different methods: DB Manager > (with an sql script) and export layer. > > However the results of these transformations are different. > I know that DB Manager uses the Spatialite engine for processing the sql > script and the results are the same as those obtained using Spatialite or > PostGIS (both based on Proj lib). > > I do not know how the export layer method produces the results. > > I expected the same results but this is not true. > > Does someone know more detailed information about this subject ? > > Here the details of the transformations > > Punto di partenza ED50/UTM zone 33N (epsg:23033) > > X Y > > 541000 4516000 > > > > > > > da 23033 a 25833 (ETRS89/UTM zone 33N) > X_Spatialite 540998,138333 Y_Spatialite 4515921,565375 > X_PostGIS 540998,138333 Y_PostGIS 4515921,565375 > > > X_QGIS_DB_Manager 540998,138333 Y_QGIS_DB_Manager 4515921,565375 > X_QGIS_export_layer 540931,341497 Y_QGIS_export_layer 4515810,597826 > > > > > > > > > > > da 23033 a 3065 (IGM95/UTM zone 33N) > X_Spatialite 540927,563731 Y_Spatialite 4515811,141068 > X_PostGIS 540927,563731 Y_PostGIS 4515811,141068 > > > X_QGIS_DB_Manager 540927,563731 Y_QGIS_DB_Manager 4515811,141068 > X_QGIS_export_layer 540998,138333 Y_QGIS_export_layer 4515921,565375 > > > > > > > > > > > da 23033 a 6708 (RDN2008/UTM zone 33N) > X_Spatialite 540927,563731 Y_Spatialite 4515811,141068 > X_PostGIS 540927,563731 Y_PostGIS 4515811,141068 > > > X_QGIS_DB_Manager 540927,563731 Y_QGIS_DB_Manager 4515811,141068 > X_QGIS_export_layer 540998,138333 Y_QGIS_export_layer 4515921,565375 > > Thanks in advance > > Antonio Valanzano > >
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