Snaphu export & overall process

Hi, I am new on this forum. I am struggling now for 2 days to create “phase to distance” map following instructions on Youtube: and other cookbooks.

I am working with 2 Sentinel 1 SLC products (IW, VV+HV) 10th may and 16th may 2019.

All steps and intermediate results seems fine, just the snaphu export seems not to work properly and consequentially all the following steps fail.

I think that the problem is, since my UnwPhase_ifg_VV_16May2019_10May2019.snaphu.hdr file is empty (1 kb), whereas coh* and phase*img files are more than 1 Gb. It also takes only 2 secs for export which indicates that there is no relevant data for export or?

I am using SNAP V7 on windows workstation.

Please advise what I am doing wrong.

if a hdr file for the unwrapped phase was generated from the export, everything is good so far. It just contains a few lines of metadata. But simply exporting the data is not enough.

Then you have to run snaphu (from the command line) with the command from the config file which is also exported.
Do you get an error message here? After snaphu is completed, a img file should be created with the same file name as the unwrapped_phase hdr. This should then also have the size of the other img files (>1GB).

After this was created, you can use the snaphu import selecting the hdr file in the second tab.

Please confirm which of these steps you have managed to complete.

Dear Andreas,
problem siolved, many thanks!!

Thanks for reporting.
Can you tell where your error was so others can learn from it?

I was not aware that files and snaphu.exe shall be in the same folder. I have learned this, now it works.

they do not necessarily have to be in the same folder, but snaphu.exe must be callable from where the data is located. This can also be achieved by adding the snaphu\bin folder to the systems path variable.

Once this folder is part of the PATH variable, you can call snaphu from any location.

Hello, sorry , but i new into InSAR mapping and also followed the video. I am stuck in Phase unwrapping, whereby i downloaded VM virtual machine to perform this task. However, as i am not familiar Linux OS, i am not able to locate my SNAPHU output. Could anyone guide me? Or share a tutorial to an alternative to not use RUS virtual machine?

the video is quite old. In the meanwhile you no longer need Linux for the unwrapping - snaphu is now available as exe file for the use in Windows and as SNAP plugin as well (menu > tools > plugins).

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Thank you very much! Yes, eventually found two videos on You Tube explaining the same.

Hello ABraun,

I apologize to bother you again.

Following this RUS video , i am able to perform D-InSAR, now i wish to perform PSI/SBAS, and i found it under Radar=>Inteferometric=>PSI. Where do you think this step goes? Does this comes instead of ‘multilook’ and ‘Goldstein Phase filtering’ ? Could you please guide me to perform PSI?

PSI is a different technique: We collected materials on how to start: About the StaMPS category

This is wonderful, I’ll have a look. Thank you very much

Warm Reagrds