Choice of DEM resolution for sen2cor


what was the reason for the sen2cor developers to choose the SRTM 90m DEM over the 30m DEM?

I’ve patched sen2cor to use a custom DEM because some of my areas of interest are >60° north and of course we can’t afford the PlanetDEM.

Now it works just fine using DEMs of any resolution (mine are 30m), but I’m wondering whether there was an actual reason for the coarser resolution besides easy availability?

The 30m results do look good and intuitively using a DEM resolution closer to my target resolution makes more sense to me. I read the DLR ATCOR manuals but couldn’t find anything saying “coarser is better”; rather the opposite when they discuss DEM related artifacts.

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I guess this can only be answered by the sen2cor developers themselves. Would one of you @umwilm or @bdpg maybe have a response to this question?

Best regards,

As far as I know the reason was to rely on a DEM which is available for the users free of charge. More, the same DEM should be used for L2-processing than is used for L1-processing. I believe 30 m SRTM-DEM was not free available at the time when this was decided.
Sure, a finer DEM is better. There are started discussions to replace the 90 m SRTM-DEM by another one. However, it is still a long way to be realized.



Thank you, that’s helpful.