Install SNAPHU using Cygwin

Hi, again!

I think I have the wrong path awhile ago. I just want to confirm if I did it correctly this time.

Thank you so much for replying immediately to my queries.

Hello! I just want to ask if it’s okay working with subsets to generate an interferogram? After doing S-1 TOPS-Split for the two products, I did subsetting to focus on a certain area and save the subset products. Then I am doing now the usual step-by-step procedure. I noticed this below my graph builder. I noticed this below the graph builder. Is it normal?

[quote=“ryeramirez, post:85, topic:4828”]
Hello! I just want to ask if it’s okay working with subsets to generate an interferogram? After doing S-1 TOPS-Split for the two products, I did subsetting to focus on a certain area and save the subset products. Then I am doing now the usual step-by-step procedure. I noticed this below my graph builder. Is it normal?

The first thing you did, was topsarsplit and apply orbit, is that right? What are the step of your processing? they are not clear to me, and would you please to share the screenshot of your graph,

Hi, falahfakhri!

I’ve solved the problem already. I did co-registration with ESD —> debursting —> subsetting —> interferogram formation —> topo phase removal —> filtering —> snaphu export —> unwrapping —> snaphu import —> phase to displacement —> terrain correction. I was able to get a displacement_VV band in the end.

I just want to ask the following:

  1. How to produce a final displacement map?
  2. How to produce a final coherence map?
  3. How do I know the unit pixel size (if this makes sense)? Or is it already the same as the spatial resolution of the SAR satellite?
  4. Can I extract time-deformation graph with the result I have?

Sorry for asking these questions. I am really just starting to learn InSAR by myself. And I am very interested with this one. I have attached here the screenshot of the displacement_VV band.

Some of your questions could be found in here,

pixel size could be identified in the step of terrain correction,

Concerning your

Since you have only one pair of two dates, the time graph, I think doesn’t work here, but you could extract your displacement results, and to do so, Please take a look at this post

Thank you so much for your immediate response! I really appreciate it. Gladly, I am taking GIS class this semester. The training module you’ve provided is really a big help. I will go through it, do InSAR using the same dataset. This will be my second InSAR training already.

Is this the pixel size?

After doing DInSAR, I plan to do PSI/SBAS as well. I think I can use SNAP also since there is STaMPS export incorporated? Am I correct? Things are getting complicated for me but I am very thankful to all the forums here especially to you.

Here is more details about the pixel size, or pixel space,

Yes, all techniques are available now,

So it is 13.93m x 3.77m (az x rng). Thank you for providing the table. I will install STaMPS soon. May I know your thoughts also about using other software? For example, DORIS and GAMMA. I’ve read that SARPROZ and SARScape are more commonly used for PSI. Unfortunately, I think these are not open source packages.

I used GAMMA in my PhD, it so flexible software, But it is very expensive, But now I think SNAP, Stamps, This great STEP FORUM, are a great substantial and alternative of any other.

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Thank you for sharing your opinion. I think I’m gonna work for now using SNAP StaMPS. Been following some forums here actually to aid my training. I want to ask you about this scheme. Is this reasonable?


I am also wondering how can I produce a final displacement map considering a reference (stable) point (in my subset) that doesn’t change with respect to time.

Thank you. :slight_smile:

Answering your first question, in general the selection of the temporal baseline, it depends on the stability of objects in your study area, the goal of your study, what kind of result you intent to achieve; The far period of S1, is 12 days and 6 days, so the selection short period promotes the quality of the coherence, and hence affects positively in most cases the quality of the produced interferograms.
I’d suggest using the same schedule but in shortest time interval.

Technically concerning your approach please take a look at this post,

and please take a look at this,

Selecting the reference point let’s call the technique you’d to preform is “stacking” it is still not supported nor the technique neither the selection of the reference point in the step of unwrapping in case of processing a single interferogram,

Here, I’d say that the PSI, SBAS technique using StamPS, is supported by command of selection the reference point, good background information of your study area helps to choose the right stable reference point, also the best master image, technically, please take a look at this post, and also you should be sure about the radius,

In here, if you mean the reference point doesn’t change corresponding to time your data selection, that’s great.

My plan is to observe the behavior of a pavement that experiences downward and upward movements during loading and unloading periods (if this is possible). This is the reason of setting the previous slave image as the new master image for the new interferogram. I have observed that in most papers, for multi-temporal InSAR, only one master image is selected and the rest are slave images (based on temporal baseline). And since I am only getting started with InSAR, I wonder if my ‘proposal’ will meet the results that I want to obtain.

From what I can see from the screenshot, the master images were different from each interferogram (please correct me if I’m wrong). If I am correct, I am now puzzled with Step 5 because it says (13.10.18 as master). More so with Step 6. I want to be enlightened.

Idea of the post I shared with you, is to create so called stacking, and this is not supported by SNAP, So what our colleague @ABraun and me is to create a multi inteferograms and then average them to get the average of ground movement or DEM, Using other software supports applying one master image and other are slaves, and also different masters and slaves. In your case I’d suggest continue to you continue in the approach you think it is true according to the literature, you should know that the test is important to reach the fact, so you should test many approaches until to reach your demand.

Reading this tutorial support you to create your fist test and also to create the graph of the displacement. Hope it helps :wink:


snaphu was running from the shell cmd, as long time the path is added as it is explained in here, but now I faced the same issue of


Do you have any suggestions to this issue, also I checked up the snaphu by navigating to the its folder and run it, it runs perfectly,

you can add the folder where snaphu.exe is located to your system’s path (restart your shell once afterwards) and then access it from any location.


Yes, the path is already added as I explained in here,

It was running but today I faced this issue,

Any updating SNAP, might be affecting and changing this issue,!

add it without “snaphu.exe”
only directories, Windows searches for exe files in all paths.

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Hi. Ok thank you,

I did, but for some reason the only way I could run the EXE was within Cygdrive (cgywin); both powershell and cmd (admin) did not work. Yet I got it working by command line.

Thank you.