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


#851

your files look extremely small (150 kb). How large is your study area?


#852

Nearly 0.9x0.8 km. I also enlarged study area but nothing has changed.

Area.kml (1.4 KB)


#853

your area (besides that it is very small) rarely has any suitable permanent targets, given that the original footprint of Sentinel-1 SLC products is 3x22 meters (range and azimuth). The longer your time-series, the smaller the chance to capture PS which are present throughout all images. You are observing almost 2 years.

To get more PS, you can:

  • increase the amplitude dispersion to 0.42 for mt_prep
  • have a larger area
  • reduce the time to one year for a start

#854

Thank you for your suggestions Andreas. I will try as your said and write here the results. Best wishes.


#855

Hi Andreas,
I reduced the time to one year, enlarged area and increased the amplitude dispersion to 0.42. It worked very well and I found 5-6 PS pixels in the study area. Thank you (:

In addition, to find more PS pixels in the study area, do you suggest any other specific hint?


#856

how many images do you use within this year?


#857

10 images between 2018.03.04-2018.12.05.


#858

are these all available? Sometimes it is helpful to use denser image series to identify more PS.


#859

I downloaded and used 10 of images. So, yes there are available. I will try the denser image series.


#860

Hello, thank you very much for providing the step by step summary. however the link you provided seems broken. could you please provide the new link?


#862

I had the same problem. Snap created an extra layer in my backgeocoded stack. I manually removed it and saved the layer. Problem solved


#863

Hi everyone
To do my Stamps processing, I encountered the following error.
Please advise me!!

Please inform me steps after export from SNAP. I have below folders.
Should I merge them? where should locate them?


#864

I have got the .csv file after the manipulate,but still i am confused to the csv chart composite, for example
image
i want to know that the dispacement in the line D 、E\ F and so on descrips the accumulation displacement or the reference displacement ?and if it is a reference displacement ,what is the date that it is compared to ?a master sar date? i just want to compare the dispalcement to levelling data


#865

My attempts to open a CSV file in QGIS are documented here: StaMPS-Visualizer, SNAP-StaMPS Workflow

thho explained it very well what the different columns and lines represent.


#866

Hi everyone, I’m stuck with my PS processing at the step of mt_prep_gamma_snapchanged; the error is this one:

Error opening file pscands.1 ij

I read that also other of you have met the same errors but I can’t figure out how to fix it.
I’m wondering that maybe is due to a low number of processed images (5 images, 4 interferograms).
Anyone can help me?

Thanks a lot guys, this is a very useful forum.


#867

I’m not sure if this caused the error but PS InSAR needs at least 20 images for proper results.


#868

Ok, I’ll process more images then.

Just for check if I made some mistakes, I attach my terminal session when I ran mt_prep:

Thanks for your reply.


#869

the command looks alright. I can recommend running the command in a newly created directory so that all generated files are stored there separately from the INSAR folder. Helps cleaning up temporary files if something went wrong.


#870

Dear all,

I see a Segmentation fault (core dumped) so probably you get something there to check it out.

I hope this helps


#871

you’re right. I was just referring to the syntax of mt_prep_snap