TopSAR Processing


#41

Thanks alot:relaxed:


#42

Cygwin is no longer necessary since we’ve included SNAPHU binaries that run directly on Windows, see:

http://step.esa.int/main/third-party-plugins-2/snaphu/


#43

Dear all,
I have applied the following steps:
Apply following methodology step by step
for deformation:

  1. S1 TOPS coregistration with ESD
  2. Deburst and Subset
  3. Interferogram Formation
  4. Topographic Phase Removal
  5. Goldstein Phase Filtering
  6. Snaphu Exprort
  7. Unwrap via Snaphu
  8. Snaphu import
  9. Phase to Displacement
  10. Range - Doppler Terrain Correction
  11. Choose a reference point

My questions are:
How can I do these following steps?:
11. Choose a reference point
12. Final map
Furthermore I would like to know if is possible to filter the zones with low coherence and if yes, I can I do.
Thanks for your help


#44

choose a pixel as reference point from terrain corrected product (with high coherence in time prefered) and check pixel value.
Next step: create a new band go to band maths (deformation band - reference point pixel value). This is the final deformation map.
Next you can create a coherence mask. Stack the final terrain corrected deformation map and terrain corrected coherence band. Create a new band to mask the coherence. Band math (e.x. If coherence band > 0.4 then 1 else NaN). You will have a new coherence mask band.
Final step: create one more new band. Band maths ( final terrain corrected defo band * coherence mask band).
This will be your final product.

p.s Don’t forget the the first basic step to apply orbit file.


#45

Thank you very much.
I’m going to try


#46

Excuse my ignorance but I’m new on SNAP :frowning:
I can not find where to apply the steps you have indicated to me.
Could you please tell me?
Thank you.


#47

https://saredu.dlr.de/unit/insar_deformation This will help you


#48

Thank you very much
cross the finger for me :slight_smile:


#49

unfortunately is not possible to registrate on the web site so I cannot download the document.
Can you help me please?
Thank you very much for your support


#50

Good morning, I ask you one last help please.
After performing the following steps:
S1 TOPS coregistration with ESD
2. Deburst and Subset
3. Interferogram Formation
4. Topographic Phase Removal
5. Goldstein Phase Filtering
6. Snaphu Exprort
7. Unwrap via Snaphu
8. Snaphu import
9. Phase to Displacement
10. Range - Doppler Terrain Correction

I have performed these operations:

  1. I considered a dipacement value at a point taken from the last band obtained (terrein correction) and I performed this math band:
    displacement_TC - value noted previously

  2. coherence estimation of the product obtained after coregistration of master and slave and interferogram formation (as per the guide you sent me)

  3. of the last product obtained I performed the math band:
    If coherence band> 0.4 then 1 else NaN

at this point I should make the last math band related to the multiplication of the new bands obtained from point 1 and point 3.

But I can not do it because they are not in the same product.
I imagine having to make a stack but I can not do it and fhurthermore the bands obtained are not stored.
Can you please tell me if the steps are correct and how can I make the stack?
Thank you.
Sorry for disturbing.


#51

when you create a new band with band maths just uncheck the box: Virtual (save expression only, don’t store data). Now your new band will be store and you can stack your product. Also before the coregistration step don’t forget to apply orbit file of your data.


#52

Thanks.
I did it but I cannot find the new bands.
Futhermore what kind of stack I have to use?


#53

use radar-coregistration-stack tools-create stack. your new band is store in the folder Bands of your product and at band maths expression editor window you can see your product bands at the left side of window.


#54

Thank you very much.
I have found it.
I’m going to try the stack


#55

Thank you.
I was able to get the final kmz file.
One last question and I do not bother you anymore (promised):
When I made the Create Stack I left the default settings except for
the initial offset method as with “orbit” gave me an exception for which I put
“Product Geolocation”.
I did well?
Are the settings correct or did I miss something?
Thank you so much for your help.


#56

it’s ok. Both methods are correct. Personally for Sentinel 1 data i am using the orbit method. But i am not so expert to tell you if one method is better than the other. You can check both methods and choose the one that you believe is better for you.


#57

Hi,I want to analayse ground deformation through a year for a region, so i have created displacment maps by generating interferogeram of all 12 month of year such as slave image and image of the first month such as master image,I mean in whole during of analysing,my master image was the first month image and the other images was slave.but now i,m confused if have i done it right or not!is it possible that I use from two images in different season!!


#58

how did you download all these images?
The copernicus hub allows me to download only two per day.
Is there another way to download many at once or even make the download automatic whenever an image of interest is available?
About what you did I think is correct but I’m starting now to approach this sector and I’m full of doubts.


#59

You can set up automatic download via “AOI Monitoring” in SNAP.

S-1 data is also available for download from ASF Vertex.


#60

The tutorial can also be accessed here: https://eo-college.org/courses/echoes-in-space/

Please keep in mind that some things changed since the tutorial was created (formerly NEST).