Snap 'StaMPS Export' GPT bug?


I face an unexpected error when using GPT for StaMPS exporting.


  1. I run Snap on a computer that is not connected to the network at all (which is not an easy task when doing registration and interferograms formation…).
    I found that while StaMPS Export takes a long time when using it from the GUI (Radar → Interferomaetric → PSI/SBAS → StaMPS Export), it runs way much faster when calling Snap Graph Processing Tool (GPT) and providing an xml graph that is set to the StaMPS Export operator.
    Using GPT with the ‘-e’ flag shows me error massages.

  2. I use Copernicus 30m Global DEM for both co-registration and interferogram formation.

To the point:
When executing the call to GPT, it starts creating the expected folders and files. After a while it starts yelling that it tries to download the corresponding SRTM dem file from
It tries again and again but can’t succeed since I’m offline. I stop the process, go to that site, download the SRTM file that it calls for, put it in ~/.snap/auxdata/dem/SRTM 3Sec/____ and calls the GPT again.
This time, it runs ok and producing a projected_dem.rslc file in the INSAR_yyyymmdd/dem/ folder. The time of formation of this file corresponds to my second call for GPT.

So, the question is - is the projected_dem.rslc a Copernicus DEM or SRTM DEM?
If it’s a Copernicus, why does it call for the SRTM one?
If it’s a SRTM, how bad will that affect the StaMPS process?

Thank you,
Oded Horowits

This has been reported here and a ticket was created: Using StampsExport with an external dem - #13 by jun_lu

You can also try the suggested fix, but I think it requires modification of the source code of SNAP.