Yeah Ok that makes sense.
Do you think it would be possible to Split the stack, export and unwrap, and then re-stack the unwrapped products? Were you looking at doing something like this in another thread? @ABraun
I was asking the same thing here because I wanted to have a stack with multiple interferograms which are all aligned to the same master but with short temporal baselines (AB BC CD…): Interferogram averaging for DEM generation
Currently we are not supporting stacks with one common master and multiple slaves but it is in our roadmap for the development. Regarding phase unwrapping indeed snaphu is unwrapping only single interferogram. You could try to unwrap in snaphu one by one, import to SNAP and stack, in theory shall work but I have never tired it
Hey all,
furthermore to above, I have another unwrapping question…
Is there any way to control which band (in a stack) is exported? I tried splitting the stack but when you re-open the separated products the slave metadata is lost and therefore (i believe) this stops you from exporting to SNAPHU.
Alternatively, I considered editing the conf file but have no idea how to calculate the “SAR and geometry parameters” nor do i wish too. My objective is to have several unwrapped interferograms over my ROI with a common master.
Any ideas would be greatly appreciated.
JB
I am very new to Ubuntu in vmware and Ubuntu in general. I want to perform 2D phase unwrapping but I am stuck at the Snaphu bit. I followed the esa tuitorial and was able to successfully do a snahu export on SNAP. In Ubuntu, I have been able to do install SNAPHU as shown in the step 1 of the image below. However, I am comletely clueless on how to open my product as shown on step 2 (same image). Kindly guide me where you got the " /mnt/hgfs…_flt$snaphu… img 21733" typed on the terminal. Thank you.
snaphu.conf contains the command which you execute in the folder where you exported the phase. It converts it into an unwrapped phase and stores it into an img file. The corresponding header (hdr) is already generated at the export.
In Linux, you right-click in the folder where your exported files are, and select “open in command prompt” or something similar (depends a bit on the version).
Then you enter the command from the text file (you don’t need nano for that, just open it in any reader) and confirm with enter. If snaphu was installed correctly, a process for phase unwrapping is started and the img file is generated. You then import it back into snap using Radar > Interferometric > Unwrapping > Import using the instructions given here: Problem in Snaphu Import section
Please note that since snaphu v1.4.2 you don’t need ubuntu any longer and can run snaphu from Windows as well without any installation: http://step.esa.int/main/third-party-plugins-2/snaphu/
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Hi There, I’m having the same issue with snaphu, when running it from the terminal I get the following message:
“Can’t open file cohIW2_VV_07Mar2016_31Mar2016.snaphu.img
Abort”
I just install SNAP 8. I had an issue before with with the S-1 TOPS Coregistration that I solved installing the libgfortran5. Not sure if this had anything to do. All the other process ran fine. Just the unwrapping is not working. Any clue what could be the cause?
Regards
Cristian O.
can you please show a screenshot of the files in the folder and share your config file?
Hello Andreas,
Thanks for the quick answer. Bellow a screenshot of my folder, and configuration file attached
snaphu.conf (1.7 KB)
Cheers
Cristian O.
somehow the coherence has not been exported with the product. Did you disable it during the interferogram formation?
I’m checking the multilook operator, and I’m able to see the coherence there, same information I see in the product explorer
I have deleted everything and running it again, but the issue remains
No idea why is just exporting the phase and not the coherence…
Because you are using a graph, we cannot exactly tell at which step the coherence is lost.
You could add an “Export” for every operator to see how the intermediate products look like and if they still contian coherence.
Dear Andreas,
Thanks a lot, there was some issue when exporting from the goldsteing filtering, I ran just the snaphu export operator I finally can see the coherence file in there, so far snaphu is running ok, I’ll keep my finger crossed 
Saludos
Cristian O.
is there a chance to see the full error message?
This is the full text
These are the files
I’m importing the .hdr file. This is the popup message when importing it
and this
I don’t know why it is there, but please remove this part of the file name so that the img and the hdr are named identical. Otherwise SNAP cannot link the hdr to the img during the import of the unwrapped phase.
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Hello Andreas,
I was hoping you could give an extra hand…
I’m having the similar issue, for some reason when exporting the snaphu files, unwrapped phase image is not exported, I’m following the next procedure:
I have generated the following graph for processing
the bands in the debursted image are
I have check them, and they look fine to me.
When I run the graph to process I get the following image and bands after the goldstein phase filtering, which seems to be fine
But when checking the SNAPHU folder I have the missing img file for the unwrapped phase
No idea why I’m having this issue
I notice that when I run the snaphu export from the menu I get the correct files (coherence and phase)
But when running the SnaphuExport from the GraphBuilder (I did created the graph about 3 different times just to check I wasn’t making any mistake) it doesn’t work properly since export less files (just the phase file, for some reason missing the coherence). Do you have any idea why this could be happening?
