Solved: Sen2cor DEM reference url?

leguide · February 18, 2021, 8:22am

Hello all,
I am using the standalone sen2cor command line tool, but the default DEM reference url in the L2A_GIPP.xml
<DEM_Reference>http://data_public:GDdci@data.cgiar-csi.org/srtm/tiles/GeoTIFF/</DEM_Reference>
seems not to be valid (anymore):

Trying to retrieve DEM from URL http://data_public:GDdci@data.cgiar-csi.org/srtm/tiles/GeoTIFF/ this may take some time ...
    [Errno socket error] [Errno 110] Operation timed out
    Download error %s, flat surface will be used

This is most likely related to “In January 2021 the source for SRTM 3Sec data which are automatically downloaded by SNAP has changed” (https://senbox.atlassian.net/wiki/spaces/SNAP/pages/321126402/Collection+of+FAQs) and Snap 8 BackGeocoding in Alpine linux Docker - #12 by vvaroquaux.

I tried to replace the url by
<DEM_Reference>http://skywatch-auxdata.s3-us-west-2.amazonaws.com/dem/SRTM90/tiff</DEM_Reference>
but sen2cor seems to directly expect a .zip file:

Trying to retrieve DEM from URL http://skywatch-auxdata.s3-us-west-2.amazonaws.com/dem/SRTM90/tiff this may take some time ...
File is not a zip file
DEM not available, flat surface will be used

Is there an URL available that is compatible with sen2cor?
Thanks,
Guido

leguide · February 18, 2021, 8:33am

I realize I did a mistake by not adding a final slash to the URL. It does work with

<DEM_Reference>http://skywatch-auxdata.s3-us-west-2.amazonaws.com/dem/SRTM90/tiff/</DEM_Reference>

Jan · February 18, 2021, 8:51am

since CGIAR updated their website, the links in Section 3.2.7 of the S2-PDGS-MPC-L2A-SUM-V2.8 have changed.

The 90m SRTM Digital Elevation Database from CGIAR-CSI is now here:

The SRTM CGIAR disclaimer has moved here:

The address http://data_public:GDdci@data.cgiar-csi.org/srtm/tiles/GeoTIFF in the SUM is now https://srtm.csi.cgiar.org/wp-content/uploads/files/srtm_5x5/TIFF/

Cheers

Jan
S2 MPC Operations Manager