SNAPHU Unwrapping

I’d love to use GMT SAR as well, especially as an addition to SNAP. But by now I found it hard to compile all parts under Windows. The installation manual is good, but there are some cases which may not be covered and I didn’t manage to get it to work.
If someone has more experience I would be greatful for a short message.

Hello Ms amighpey
In addition to deburst problem, It worth’s to mention that:
phase unwrapping with snaphu sometimes result phase jumps due to using tiling option.
I suggest that use a subset of image, then apply phase unwrapping with no tiling option(tile number=0 for row and column).
Best regards
Sayed Javad Adabikhosh

Hello!
I need some help guys!

So these are my results… as you can see the unwrapped phase has no sense…
I used DEFO, because I am looking for deformations and they are visible when you look at the phase image.
DO you have any idea why I get this result after unwrapping? Or where is my mistake… I used the graph deformation-pre-proccesing.

Thank you,
Alex

Hi Alex,

Would you please to reframe your question

Hi! So I want to see the surface displacement after an earthquake. I used SNAP. I used 2 IW images. I split the images, deburst them and after that merge them. After that I use the graph deformation-pre-processing (orrbit correction, stacking, cross-correlation, warp, topo phase removal (I used the 1sec SRTM) and the golstein phase filtering). After this process I obtained the left image (this is just a subset). After that I used Snaphu export with the statistical cost mode DEFO. After I used a virtual machine with linux so I can run snaphu. The result you can see it in the right image. And now I look at the 2 images and I see that something is wrong and I don’t know where the mistake is. In the center of the left image you can see the epicenter of the earthquake, so that image I think is ok, but the unwrapping is for sure wrong. Do you know what I did wrong in this process?

Regards

Hi,

Would you please to follow these steps,

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Also try to play with the parameters

The images have the same track… and I couldn’t find SM images for the dates I used or around that dates.
Thank you for the suggestion, i will try these steps.

Thank you!

I’m beginner in InSAR.

I’d unwrapping the phase using the SNAPHY algorithm (using windows).

basing on the Sentinel-1 Toolbox tutorial, I should find snaphu.conf file in the the folder /mnt/hgfs/ .

I don’t find it!!

help? thank you

snaphu.conf is created when you export the phase with SAR > Interferometric > Unwrapping > SNAPHU export.
It can be found at the location you choose as a target folder:

If you are using the VMWare image in the tutorial, you need to setup the shared folder. In VMWare player, go to edit virtual machine settings and then options. From there setup a new shared folder. Put the data you export from SNAP into this shared folder and then in the linux virtual machine, you will see the data files in /mnt/hgfs/

yess, it works !! thank you

Iveci,
There is a training session (SAR interferometry) scheduled soon?

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Hello all,

I have followed these steps of the ESA tutorial to extract an interferogram for my area of interest. It’s my goal now to unwrap it, so that I can calculate the water level of a lake. I have never worked with satellite imagery before, so I would like to find a simple way to do that. I already have Matlab in my computer installed, but I still can’t understand how can I import there my unwrapped data in order to use the algorithm below:


Should I carry on trying to get results with Matlab or is it maybe simpler to dual boot Linux in my Windows PC and work with SNAPHU?
I am sorry if my question is silly, but I’ve been reading loads of things for days and I can’t get to a conclusion…:frowning:

Hi,

Some hints you could find in SAR-EDU_Tutorial_Focussing_Matlab.pdf from https://saredu.dlr.de/

But you could implement the unwrapping step by using snaphu under linux or unix machine,

thank you for replying. I have worked so far with a pair of slc images in SNAP and I have an interferogram as a result. I want to unwrap it through matlab but I can’t figure out how to import the SNAP data in to Matlab.

Hi,
I don’t think it is done before, but I’m keen to know how as well if you have any results

ok, good to know! thanks

Hi,
An other way to speedup the unwrapping is to increase the number of processors in the configuration file for snaphu, In my case it was set to 4 by default but when i tried to unwrapped on a 24 core work station using Snaphu/CygWin I increased the number of processors to 20 in the config file and it worked like a dream. You can set it to a higher number in SNAP while exporting to snaphu. You would only be restricted by the physical number of cores on you machine

Regards