Hello everyone,
I am working in QGIS 4.0.3-Norrköping and I am encountering an unexpected shift when working with different coordinate reference systems.
I have a reference dataset in EPSG:3003 (Monte Mario / Italy zone 1) and a second dataset defined as EPSG:7791 (RDN2008 / UTM zone 32N).
When loading the EPSG:7791 layer into the EPSG:3003 project, I observe:
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If the layer is kept as EPSG:7791, the point is shifted by approximately ~77 meters compared to the expected position.
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If I instead assign EPSG:3044 (ETRS89 / UTM32N), the point shifts by approximately ~0.7 meters, which is much closer to the expected position.
The layer is explicitly defined in its PRJ file as:
RDN2008 / UTM zone 32N (EPSG:7791)
What makes this issue more puzzling is that until a few months ago I did not observe this kind of discrepancy. Previously, I would only see residual differences on the order of ~50 cm in similar transformations.
I have already tried reinstalling QGIS, but the issue persists. I also asked a colleague, and they are experiencing the same behavior on their setup as well.
Any insight into the PROJ transformation paths used in this case, or possible recent changes in default transformation behavior, would be greatly appreciated.