O.K. land/sea bitmaps can also be applied in SNAP. But
I decided now to go in the direction of Pytroll/SatPy.
It's easier to script and that's what UNIX is all about.
The glitch in the BMP header seems not to be a problem
for David's software or Microsoft Windows Photo Viewer.
And *YES*: UKW-Technik that was the receiver I started
with using a 3m dish for Meteosat and a crossed dipole
for NOAA satellites in the early 1990-ies at my school.