Hi,
We are processing Proba-1 CHRIS data from L0 to L1, creating COG format outputs. The COG file is tagged with nodata = 0.
In version 11 of SNAP, this works correctly. The missing pixels have a value of 0, reported a NaN, and the automatically generated no data mask correctly masks out these pixels.
When updating SNAP to v13, it now shows the no data pixels as having a value of -1. I am not sure why it does this. As a result the no data masks are blank as there are no no-data pixels to mask out (as they have a value of -1 instead of the expected 0).
I tried changing the layer settings to show the no-data pixels as 0. It then correctly shows them as 0 instead as -1 but it doesn’t change/update the no-data mask.
Why is there this change between SNAP versions and what can I do about it? It seems like SNAP isn’t reading the COG tag correctly. Or is -1 the standard no-data value we should use, i.e. change the COG tag to -1 for no data.
Thanks in advance for your help and advice.