Sentinel-1 Terrain Correction fails with partial water coverage

Hello

I recently was trying to terrain correct a Sentinel-1 image. The image covers land and water.

The problem seems to be that when SNAP searches for a DEM it expects one must exist. The image I am using (S1A_IW_GRDH_1SDV_20201104T224257_20201104T224326_035105_0418C7_545E) has the north east corner that puts part of the image in the N12W068.SRTMGL1.hgt.zip tile. However, the N12W068.SRTMGL1.hgt.zip does not exist since it is all water. However, the s/w repeatedly looks for the DEM and tries to unzip it:

SEVERE: org.esa.snap.core.dataop.dem.ElevationFile: error in opening zip file
INFO: org.esa.snap.core.dataop.dem.ElevationFile: http retrieving http://step.esa.int/auxdata/dem/SRTMGL1/N12W068.SRTMGL1.hgt.zip
SEVERE: org.esa.snap.core.dataop.dem.ElevationFile: error in opening zip file
INFO: org.esa.snap.core.dataop.dem.ElevationFile: http retrieving http://step.esa.int/auxdata/dem/SRTMGL1/N12W068.SRTMGL1.hgt.zip
etc…

Its seems that SNAP does nto understand that the absence of a tile must indicate the cell is all water, I think.

All the best,
Pablo

2 posts were merged into an existing topic: GPT: New SRTM ZIP-files corrupted