SNAPHU Unwrapping


Agreed with Joseluis, really hoped that someone with experience can help!


Hi all

I have the same problem: Unexpected or abnormal exit of child process… for unwrapping ALOS PALSAR images!!! Help!



did you try this?


Hi ABraun, yes, I did, but It gives the same error :cry:


hmm, what is your intention? Making a DEM or estimating subsidence?
Maybe you can try TOPO / DEFO / SMOOTH (whatever you chose first) or try to change MST / MCF.


Hi again, I want estimates of subsidence! I did this with DEFO and MCF.


Play with tiles until sucseed


Hi, I did with 20-30-40-50-60-70-80-100 and nothing!!! I don’t know what happened!!! :cry:


Hi, if you are using virtual machine to unwrap, you have to increase the ram and disk space. Works for me.


Hi Pancho, I’m not using virtual machine!:confounded :confounded:
I’ve done it for Sentinel!!! but with Palsar I can’t yet.


I’m a Windows user so i’m using Linux in virtual machine to do the snaphu phase unwrapping, and i got the same problem Unexpected or abnormal exit of child process… working with sentinel 1 I just increase the ram and the disk space and it Works. Maybe for Alos palsar could be the same.


Hi all

I did the unwrapped of ALOS PALSAR images, now I will do the calcules to subsidence in an area of interest!

This is the firts result:


Hi Shubham, I’m new in this forum. I read that you resolved the problem, could you explain me what’s the problem with the snaphu data import message “3-SnaphuImport: java.lang.NullPointerException”? I have 2 images S1 and I have used S1 TOPS Coregistration, Interferogram formation, Golstein phase filtering, S-1 TOPS Deburst, Snaphu export, and when I try to import the data into NEST DAT 5.1 appear that message.

I hope that you can help me.



A post was split to a new topic: Acces to InSAR data (Sentinel / Alos)


Hola Jose Luis, yo tambien soy de Colombia y estoy probando con S1 y SNAP, sin embargo tengo problemas para realizar el UNWRAPPING, exporto los datos y trato de seguir el proceso para ejecutarlo en CYGWIN pero no obtengo resultados. Podrias darme una mano con este problema?

I try to arrive to the step “phase to displacement”, therefore I followed S1 TOPS coregistration -> interferogram formation -> S-1 TOPS Deburst -> Topographic phase removal -> Goldstein phase filtering -> SNAPHU export, after, I try to run into cygwin with the following steps: copy the exported files (not folder) to bin folder of SNAPHU-> Open snaphu.conf file -> Run Cygwin as admin -> navigate to bin folder -> Type and execute the command in the conf file, however when I try to execute cywin only appear

Pasted image1680x1050 140 KB
I don’t know if I’m doing something wrong, I hope that you can help me, I only have two weeks to use the computer of the laboratory.



hei gabriel when you import to snaphu (snaphu import), please tell me what you input in 1-read-phase , mine cant work well. thanks


hei all when you import to snaphu (snaphu import), please tell me what you input in 1-read-phase , mine cant work well. thank


Hi Arbad

The input is the image processed before of the export for SNAPHU

Problem in Snaphu Import section

Hi Gabriel

Thankyou for your reply and information, so its mean processed after dinsar and filtering right ? I used ALOS Palsar data but the coherence seem to be like noisy, I cant see anything, have you recommendation ?



Hi Arbad

Yes, after dinsar and filtering. Which is the objetive of your study?