I was wondering could anyone help me with that I used S2-L1C resampled data try to get the chl-a result. However after C2RCC the result is wrong as some of the area of my lake are missing (like gone…only show partial of the lake on the screen). How can i fix it???
Also, If i want to compare the in-suit data and the chl-a result which get from express (21.0*(iop_apig)^1.04 is that enough to find the relationship between observed data and modelling results?? Do i need to do other calculation (band math)in snap after C2RCC??
If part of your data is “gone”, probably it is because the data was not of good quality, and some flags have been raised and applied (clouds, sun glint…).
For comparison of chl predicted vs. in situ you can use a simple linear regression.
Thank you for your reply.
However, the raw image (I mean the RGB image) shoed no clouds covered on top, but the C2RCC result still has some part is missing. Can I fixed it through some ways maybe?
Maybe the valid-pixel expression does not work for your scene, and you need to adapt the expression.
The expression is meant to exclude land pixels from the processing.
I see what you mean now, some of the value show in the flag are “invalid pos”, and it might need to fixed before run the C2RCC.
BTW, when I compare the OLCI predicted CHL data with the in-situ data, can i used the conc_chl? or it is better to use the data after compute from the express (21.0*(iop_apig)^1.04?
I see. So I can adapted the chl by change the factor according to my region of interest.
If there is no much change, then I can just use the conc_chl to compare with my observed data to find out the relationship between them.
Am I right and am I understood you clearly?
Thank you
Hi Marpet,
sorry for bothering your again.
I am trying to fix the S2-L1C project missing area after C2RCC. As you told me that might need to change the valid-pixel expression, however, could you help me to understand what is B8>0 AND B8<0.1 stand for? is that within 0.1-0 range is exclude the land pixels?
thanks.
Yes, only if pixel of Band B8 are within the range of 0 to 0.1 the pixels are considered valid and are processed. This shall exclude all the land pixels.
So I do not need to change the expression, but need to check with the pixels value of Band B8 to double check if it is within 0 to 0.1?
If not, then I need to change the expression ?
Am I right?
There is also the Coastal Water processor from FUB and CSIRO s3tbx-fub-csiro/s3tbx-fub-csiro (github.com). At the moment it still suffers from issues in SNAP, but this will be fixed in the coming weeks.