How to prepare Sentinel-1 images stack for PSI/SBAS in SNAP 5


#390

Hi all,
Recently SNAP6.0 has been released, and by chance @Mehdi use the “oethorectified lat/long” options to solve his problem. And now I test this method and find that this new option can solve the shift problem and can avoid Terrain Correction (TC) step in PSI. @katherine @annamaria @bayzidul @ABraun
Here is the new Interferogram Formation window in SNAP6.0:

After finish this step, elevation and lat/lon band will be generated in result product.

Start from Deburst step, we get Stack_deb, then create a subset, get Subset_Stack_deb, form interfeorgrams as the first picture showed and get Subset_Stack_deb_ifg. And then use Subset_Stack_deb and Subset_Stack_deb_ifg to export to StaMPS.
And that’s all, all the things have been done. Add Elevation band, geocoded and topo_removal are doing together in interferogram formation step, TC are avoided, lat/lon file can export correctly without saving to GAMMA format.

Here are some results:
1.use SNAP6.preview4 and without TC:


2.use SNAP6.preview4 and TC:

3.use SNAP6.0 oethorectified lat/lon and without TC:

Note: I use different parameters when export to Google Earth, and only about 20% PSs are shown in the picture, so don’t be surprised that PSs location are not exactly the same.

In SNAP6.preview4 or preview5, without TC there are exist shift problem. And use SNAP6.0, shift problem has been solved and TC are no more needed.

Have Fun!
Fei


Workflow between SNAP and StaMPS
About the STaMPS category
#391

that’s just fantastic, thanks for testing!

One question about the stack: Did you create pairwise stacks of AB AC AD… and merge them with the back geocoding as originally suggested? Because this creates a quite redundant stack with A in it multiple times and I wondered if this is the best way to do it.


#392

Dear ABraun,
I follow the step as katherine suggested here:


And my post can be seen as a suggestion for the orignal way.


#393

Dear Fei,
Thank you so much for sharing your wonderful experience! Due to our cooperation the workflow between SNAP and StaMPS becomes more and more friendly! The next problem seems to be the possibility to create a stack of pairs with different masters (being resampled to one “supermaster”) and export such a stack to StaMPS to execute the StaMPS SB (Small Baselines Processing). StaMPS SB will be very useful in rural areas where StaMPS PS permits us to identify only few PS (especially using S-1 images)…
All the best,
Katherine


#394

Hi @kouhartsiouk @Fikretjfm

I have a problem during the processing final, the process stopped for 20170409, and when I check the folder .rslc I can see the archive 20170409 duplicate, someone had the same problem?

Thanks for advance


#396

Dear Katherine,
Thank you for your reply, I also notice that almost all the PSs points I get are located in urban area, and get only few PSs in rural area. It’s a shortage for StaMPS PS method, and can hope SB method to improve it.
But it seems that the implemention of SBAS export in SNAP have to wait a long time…:joy:
All the best,
Fei


#397

maybe the file was still in use by another program? Does it always happen with that date?


#398

hi ,
have you tried to delete one of them? I havent faced such a this error.
Fikret


#399

Thank you for the test-report Fei!


#400

Hello,

in the last weeks I tried using the SNAP-StaMPS workflow for PS analysis. I found this thread which was incredible helpful. I summarized…again…the workflow, I found the summaries and hints given were great @katherine, @bayzidul, @FeiLiu, @ABraun. But latest updates of SNAP and the amount of steps are confusing, gathering and following all hints given to reach the goal.

Maybe some of you which have experience in the workflow might have a look at the summary to help improving it.

Furthermore I would really like to do all the steps with a test dataset to retrieve a valid displacement map and write a comprehensible tutorial. I do not have data for validation, hence I am just starting using interferometry. Therefore I do not know if outputs produced are valid or not…maybe someone can help me to do this, just write me a message here.

To read the summary, download the .html here and open it in your browser.

Thank you :slight_smile:


Linux Installation using StaMPS and S-1 data
Urban subsidence steps( wok flow) with sentinel 1 or radarsat data
Linux Installation using StaMPS and S-1 data
SNAP Error: Again Failed to Open İmage after deburst and after Split
Using snappy with SNAP built from source to run changed Op
#401

Wow, thank you for compiling all this and of course thanks for sharing it here!


#402

That’s great, Thorsten. We should add this to our tutorials section when it has a good status and if you allow. But then it should be at a better place where we can easier link to.
Unfortunately, I can’t help with the validation. I have no knowledge of the domain.


#403

Hi @thho

This is an outstanding work you have done. The document is a great support to the enthusiasts. Thank you so much.
The validation is a tricky process, you can either validate your result with GPS or Levelling based reference data or you can use another software to compare. There is a lot of papers on this that might help you.

Thank you


#404

Hi all, I have used SNAP6, and
@katherine 's and @FeiLiu 's changed script and followed the lastest workflow of @FeiLiu. I can successfully run the SNAP and StaMPS and get the final result.
However I found a new problem about DEM data from SNAP exported. It seems this DEM cannot be recognized and cannot be used by StaMPS. I added the elevation data in SNAP and can find the DEM file at the dem folder in the exported folder.
I found this problem, because of:

  1. When I try to used “ps_plot(‘v’,2)” to plot a shaded relief topo as background, StaMPS returned an error “Cannot find demparms.in in this directory, parent or grandparent”
  2. When I try to used “ps_plot(‘v-a’)” to plot a result that minus topo-correlated atmosphere, StaMPS returned an error “Unable to read file ‘./tca2’: no such file or directory.”
  3. I have compared the results of “ps_plot(‘v-d’)” and “ps_plot(‘v’)”. They are exactly the same.
    It would be appreciated if anyone could help me.

Linux Installation using StaMPS and S-1 data
#405

Thanks for your kind replies @ABraun, @marpet and @bayzidul!

It would be great to see the final result in the tutorial section. The domain I used to store the document allows me to update it frequently. I want to avoid numerous links to different versions but one source at all. In the end a final result can easily be stored wherever it fits best.

Concerning validation, I will dive in some literature and maybe there is a SFM product which could help me…I will keep you on track. But if someone might help me, you are welcome!


#406

Help from user thho

file:///C:/Users/User/Desktop/snap_stamps_1_0.html#26_triangle

You can look for him in the forums


#407

Hi YuL,
There does exist some omissions in processing, but they don’t influence final result.

  1. It because StaMPS does’t generate it’s own DEM file when processing, but it doesn’t mean export DEM file cannot be recognized, you can generate it by yourself if you want.
  2. It because StaMPS cannot find atmosphere file ‘./tca2’, I don’t know how to generate this file, either, it seems generated by other programs, maybe TRAIN?
    3)They looks same, but they are not, they calculate different way.
    Hope this help,
    Fei

#408

Thats nice what you did! We shall see the way to validate your tutorial and indeed add it to our tutorials .What do you think @mengdahl ?


#409

Yes, great idea. We should create FAQs for the toolboxes and SNAP in general and link to external tutorials from there too.


#410

Hi @Fikretjfm

Thanks for your support

The last step processing give me this error!!!