I have run into problems with reprojecting OLCI radiance and retaining the quality masks. examples below are from a S3A_OL_1_EFR…SEN3 file before and after reprojection with the bright pixel flag raised. can you advise how to retain the mask definition?
There seems to be an issue with the no-data value of the flag band.
If you disable the usage of the no-data value before doing the reprojection the result looks better.
Just right-click on the ‘quality_flags’ band and select Properties from the context menu.
In the dialog simply remove the check mark from the property No-Data Value Used.