I recently projected a raster from EPSG:6340 (NAD83(2011)/UTM zone 11N) to EPSG: 32611 (WGS 84/UTM zone 11N) using the "Warp (reproject)" tool in QGIS (i.e., the gdalwarp). I noticed that there was a minor shifting issue for 1.1m for X and 0.5m for Y.
I further used the Project Raster (Data Management) in ArcGIS Pro to apply the same projection and got much better result.
I was wondering why these two tools result in such a different result. I started concerning if the gdalwarp is working correctly.
I did a small test using one test point as follows:
Test Point EPSG 6340 > X: 382794.912012 Y: 3764790.23875
(1) Reproject the test point to 32611 with ArcGIS Pro X: 382793.794251 Y: 3764790.79647
(2) Reproject the test point to 32611 with QGIS X: 382794.912012 Y: 3764790.238854
There are 1m and 0.5m off on X and Y.
Best Answer
If two different software give different results it is impossible to say which one is shifted. There should be a third authorized reference that is known to be correct. ArcGIS Pro also seems to support 9 different transformations between EPSG:6340 and EPSG:32611. I did not test those but I suppose that they would give slightly different results.
QGIS is using Proj and that library supports only one transformation
It seems that for Proj, GDAL, and QGIS the tranformation NAD83(2011) to WGS 84 (1) does actually nothing
By this closed Proj ticket it is correct to do nothing https://github.com/OSGeo/PROJ/issues/829 and also https://www.uvm.edu/giv/resources/WGS84_NAD83.pdf states that "For all practical applications WGS84 ellipsoid and GRS80 ellipsoid are identical."
However, there seems to be different NAD 1983 realizations and this may lead to shift of about a meter https://community.esri.com/t5/coordinate-reference-systems-questions/grs-80-to-wgs84/td-p/849211. The ESRI engineer suggests
For sub-meter accuracy you should probably know also the epochs (times) of your source data and into what WGS84 epoch you want to do the conversion. Proj/GDAL/QGIS do have support for dynamic coordinate systems nowadays https://gdal.org/user/coordinate_epoch.html but I do not really know how they are used.