I apologise if my question is very simple.
I need to apply terrain correction on some SAR images, using SRTM 1sec HGT as DEM. However, the computer that I will use for pre-processing don’t have internet access. Can anything help me?
PS: I will use the gpt by command line. I will not use SNAP with graphical interface.
you can download a DEM as long as you have internet connection (or transfer a DEM file from another computer that covers your area) and then select “external DEM” as a source for the Terrain Correction module.
Just make sure that your DEM is projected in WGS84 for Terrain Correction, regardless of the chosen output projection.
You can download the SRTM 1 HGT tiles (supposedly on an internet connected machine) and copy them in the directory ~/.snap/auxdata/dem/SRTM 1Sec HGT on the machine that processes the SAR imagery. Make sure you have ALL tiles that cover your frames plus a buffer around it.
You can use wget to pick up the tiles:
wget http://step.esa.int/auxdata/dem/SRTMGL1/N49E004.SRTMGL1.hgt.zip