I’m using the Sen2Cor280 Processor plugin for SNAP. I want to change top-of-atmosphere L1C Sentinel-2 imagery to bottom-of-atmosphere L2A. I wasn’t sure what the Processing Parameters should be set at, so I figured I’d try winter/summer/auto on a recent 2019 L1C image, and then compare my results to the identical date L2A imagery that ESA provides with EO Browser. (That way, if my pixel values matched ESA’s, I could feel more confident I’m using the tool correctly.)
However, when I tried this, the values produced by Sen2Cor didn’t match the downloaded L2A values. As shown in the attached image comparing values for a pixel in the red band using ArcMap, the first value (30) is from the downloaded image, and the other three are values for the same pixel produced by Sen2Cor under different parameters (all 451 - apparently the setting’s not too sensitive).
Most of the pixels are like this, with the Sen2Cor values being very high and downloaded L2A values being lower than 100.
What I’m doing with Sen2Cor seems to be wrong. But I’m not sure where. I unzip the L1C, load in the xml, and run Sen2Cor on all resolutions with the defaults.
Has anyone had a similar error, or have any suggestion on changes I could try? I’m grateful for any feedback on it.
Tile: T18NVG, date: 20190404T152641.
Thank you for your help.
Thank you for the links. I’ll look through those topics.
In the meantime, to answer your question - I suspect my use of Sen2Cor is wrong or incomplete because when I compare my BOA correction using Sen2Cor to the BOA product for the same tile/date, the BOA correction that I produced with Sen2Cor differs from the professionals’ results by a lot, ~200-600 per pixel. I’m trying to replicate the ESA BOA correction process using their tools. If I were doing it correctly, I think my BOA results should have identical values to the ESA’s BOA product for that same tile/date.
Dividing by 10000, I still have that problem. For example, for a pixel where ESA’s value is 36 and my value is 619, dividing by 10000 makes my value .0619, still very off from the ESA product.