ACOLITE forum

Hi Emanuele There is no need to give such long settings files to ACOLITE, because there are some settings that do not necessarily make sense for S3 processing. For best results , provide a settings file changing only the settings you want to change. Do not just copy an output settings file from anot...

Hi Thomas

Thanks for sharing - I presume you convert this to a L1R.nc file before passing to ACOLITE? Could you also share this NetCDF?

The only thing I can see at the moment is the slightly wider coverage by B8.

Quinten

Hi Thomas

Do you also happen to have the file for 2022-04-06? To compare with your original post.

Does the strip correspond to the slightly larger coverage by the pan band (B8)?

Quinten

Hi Patricia I'm glad your issue is resolved! It would be useful to compare the negatives that are introduced by the glint correction, as in this lake the 1020 may be influenced by mixed pixels and adjacency. For most settings, the values from the general defaults.txt will be used, replaced only with...

Hi Philippe I will respond in a separate post about the l2_flags. This is not required to solve your question, but may be useful to understand. Indeed each pixel can hold only one integer value, but these are represented by a combination of bits. If we assign a specific flag to a specific bit, we ca...

Hi Philippe Thanks for the clarification, as I was misunderstanding your question! When l2w_mask=False none of the masking tests I linked to are actually performed, and the l2_flags are not used to mask any dataset in the L2W NetCDF. The reason why the Nechad algorithms still contain NaN values when...

Hi Philippe To get the full mask where bit one (1) is set, you need to do a binary AND test, not just test for pixels equal to 1. E.g. flag values 1, 7, 9 all mean the first bit is set and hence the SWIR threshold has been reached. In the case of 7 also second (2) and third (4) bits are set (1+2+4 =...

Hi Philippe Thanks for your perspective on the ACOLITE masking! Most of the time I get complaints about the masking, so it is nice to hear that it's perfect. 8-) I myself think the defaults are passable but not universal. Indeed for turbid or inland waters NDWI can give poor performance. Most of the...

Hi Thomas I can't reproduce those with a current clone of the ACOLITE repository, and I don't see any settings in your file that would impact masking. I used scene LC09_L1TP_015028_20220406_20230421_02_T1 obtained from EarthExplorer and this WKT polygon 'POLYGON ((-73.45349878472959 45.7232128558407...

Hi Patricia For older versions of ACOLITE the l2w_mask_smooth option was always on, which adds a buffer around the masks and explains why your narrow lake is masked even by disabling negatives masking. The new default for OLCI is l2w_mask_smooth=True, and you could try specifying this even in versio...