downloading Sentinel-2 Data Products (urn:eop:VITO:CGS_S2_L1C)
There seems to be a difference between Sentinel-1 and Sentinel-2 when it comes to downloading the product (as a .zip file) and opening it with ESA's Snap application.
The S1 products are downloadable as a zip .file. The URL of this file is present in the response payload for a search (path: features.properties.links.data.href).
URL of the search:
https://services.terrascope.be/catalogue/products?collection=urn:eop:VITO:CGS_S1_SLC_L1&collection=urn:eop:VITO:CGS_S1_GRD_L1&start=2021-12-29&end=2022-01-06&geometry=POLYGON((6.352433189749719%2049.90370356672262,%206.457901671528817%2049.90370356672262,%206.457901671528817%2049.949002521470284,%206.352433189749719%2049.949002521470284,%206.352433189749719%2049.90370356672262))
URL of the .zip file:
https://services.terrascope.be/download/CGS_S1_SLC_L1/IW/DV/2021/12/30/S1A_IW_SLC__1SDV_20211230T055052_20211230T055119_041234_04E67C_EBE5/S1A_IW_SLC__1SDV_20211230T055052_20211230T055119_041234_04E67C_EBE5.zip
The product can be open in Snap.
The S2 products (only tried for urn:eop:VITO:CGS_S2_L1C) are downloadable as a collection of individual files.
URL of the search: https://services.terrascope.be/catalogue/products?collection=urn:eop:VITO:CGS_S2_L1C&startIndex=1&count=10&start=2021-12-30&end=2022-01-07&geometry=POLYGON((6.284214053303004%2049.892271728044,%206.330356765538455%2049.892271728044,%206.330356765538455%2049.93758147405905,%206.284214053303004%2049.93758147405905,%206.284214053303004%2049.892271728044))
URLs of some files (3 out of 104):
https://services.terrascope.be/download/CGS_S2_L1C/2022/01/02/S2B_MSIL1C_20220102T104339_N0301_R008_T31UGR_20220102T113621/S2B_MSIL1C_20220102T104339_N0301_R008_T31UGR_20220102T113621.SAFE/manifest.safe
https://services.terrascope.be/download/CGS_S2_L1C/2022/01/02/S2B_MSIL1C_20220102T104339_N0301_R008_T31UGR_20220102T113621/S2B_MSIL1C_20220102T104339_N0301_R008_T31UGR_20220102T113621.SAFE/GRANULE/L1C_T31UGR_A025202_20220102T104336/IMG_DATA/T31UGR_20220102T104339_B03.jp2
There is an endpoint that allows for the download of the files (indicated as the payload of the HTTP POST request):
https://services.terrascope.be/package/zip
I noticed this endpoint by means of reverse-engineering, analyzing the "viewer" application in the browser.
There seems to be no documentation on this endpoint. It would be great to have more info, it would be great to know if (and how) it could be parametrized/configured.
The result of this call is a .zip file. However, this .zip file presents some issues and it is not usable as such: Snap cannot open the Terrascope product, neither the desktop application nor the Java lib. I tried to manually adjust (as described below) the .zip file, still, I cannot open it with Snap.
The following analysis is made by comparing the same product downloaded from two providers Terrascope and Creodias.
URL of the search (Creodias):
https://services.terrascope.be/catalogue/products?collection=urn:eop:VITO:CGS_S1_SLC_L1&startIndex=1&count=10&start=2021-12-29&end=2022-01-06&geometry=POLYGON((6.352433189749719%2049.90370356672262,%206.457901671528817%2049.90370356672262,%206.457901671528817%2049.949002521470284,%206.352433189749719%2049.949002521470284,%206.352433189749719%2049.90370356672262))
URL of the .zip file (Creodias):
https://zipper.creodias.eu/download/74a8f296-e256-5806-b0e7-709b56f259b4
The inner path of the file:
Creodias: S2B_MSIL1C_20220102T104339_N0301_R008_T31UGR_20220102T113621.SAFE\MTD_MSIL1C.xml
Terrascope: CGS_S2_L1C\2022\01\02\S2B_MSIL1C_20220102T104339_N0301_R008_T31UGR_20220102T113621\S2B_MSIL1C_20220102T104339_N0301_R008_T31UGR_20220102T113621.SAFE\MTD_MSIL1C.xml
Changing the inner path, alone, does not fix the problem. It might be, however, a required step.
Compressing method:
Creodias: the inner directories and files are not compressed, the size and packed-size values are equal. The method is Store.
Terrascope: the inner directories and files are compressed, the size and packed-size values are different. The method is Deflated for files, not declared for directories.
Changing the compressing method (meaning to archive but not compress the files) still does not fix the problem.
Attributes/Permissions of the inner directories and files:
Creodias: directories: D drwxrwxr-x & files: -rw-rw-r--
Terrascope: no attributes
It might be an issue of file-visibility. Snap manages to see the MTD_MSIL1C.xml file and the GRANULE directory, but cannot see the children-files of GRANULE.
