Surface Subsidence

Microwave Toolbox Interferometry
#6

I can think of two options here:

  1. Calculate an average coherence with the band maths and apply one threshold (0.5 seems too high for a mean value because the raster values will generally be lower after the averaging and not many areas will remain. Maybe 0.3)
  2. Apply a threshold of 0.3 for every coherence image to get 5 binary masks. You then multiply all masks and have values of 1 remaining at pixels which were above 0.3 at all times and 0 where coherence fell below the threshold at least once.
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#7

thanks for your reply,

I forgot to ask about multilooking. Many suggest that multilooking improves the quality of the image? does it make the SAR image smoother?

Do you recommend multilooking as an important step? if yes, do we do multilooking at the very end of the InSAR process?

thanks

#8

multi-looking can improve the image/interferogram quality, but inevitably reduces the resolution. So if you don’t depend on the resolution of 10 meters of S1 you can perform it, but it is not required at all.

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#9

hello everyone,
talking of the multi looking, i remarked that the resultant displacement obtained with a multi looked interferogram is different from that without multi looking the interferogram. is it due to the reduction of the resolution as said by @ABraun or something else. also which is more reliable, with or without the multi looking?

my second question is how do i add a stable point in my displacement map. following the tutorial from ESA, when i take the pixel value and add to the displacement map, it affects the lower but also the upper bound of the displacement histogram. i looks strange to me, is there a proper way to do it?

thanks.

#10

hi all,
I am trying to find out subsidence in a particular area. I am using sentinel-1 data set for that and till now I have done

  1. Coregistration 2. Interferogram generation 3. Deburst 4. Topographic phase removal 5. Goldstein phase filtering
  2. Snaphu Export 7. snaphu Import 8. Terrain correction now what should I do for further processing(what step I should follow) and finding the Subsidence of particular area?
#11

Please follow this topic Subsidence map in 3d view
It starts exactly at your step.

#12

@john_chamber can you be more specific on the stack processing?

#13

Hi John,
I’m using around 10 images for Subsidence studies,I updated orbital file and TopSAR-split, please tell me how to run batchprocessing for these ten images(1-2image, 2-3 image , 3-4 image and so on).
And then how to add these output to a single image ?
please clarify this doubt…

Thanks
Suribabu

#14

currently, SNAP only allows single master interferometry (1-2, 1-3, 1-4).

#15

Thank you so much ABraun.
Please tell me how can i add these (1-2, 1-3, 1-4 ) SAR interferometric images to a single image (single output).
Means how can i add these images (1-2, 1-3 and 1-4) to a single image.

#16

Please suggest me which method is more beneficial for subsidence studies in urban areas. (1-2, 1-3, 1-4 …etc) and (1-2, 2-3, 3-4…). based on that I will do manually.

#17

have you seen the subsidence tutorial? Sentinel-1 TOPS interferometry
The last section gives a suggestion on how to combine images of multiple dates.

#18

Thank you ABraun…

#19

Dear ABraun
I followed the above tutorial (Sentinel-1 TOPS inferferometry) steps and created this below displacement chart from 2017-2020. shown in below figures.

plot1
plot1854×813 862 KB

plot2
plot21920×1080 328 KB

I stacked all the 12 displacement images(1master+11slave). and then Using Band Math i created one displacement_combine ((1+2+3+…12) / 12). then
how can i create profile plot from 2017-2020 displacement ?
and please tell + and - values indication in google earth map (means which part is uplifting or subsiding) ?

#20

first you digitize a line, then you select the profile-plot tool
grafik

  • means movement tpwards the sensor and - away from the sensor in line-of-sight.
#21

Thank you so much ABraun.

  • upliftment
  • subsidence
    is it correct sir?
#22

Upliftment (+)
Subsidence (-)
is it correct sir?

#23

This depends on the date of your first and second product. The movement is given between the date of the master and the date of the slave image.

#24

Dear ABraun

This is the final output of around 19 final Terrain corrected displacement stack. But in this final image the upper area is not clear. please check it once.
displacememt_dsp_TC_Stack_new_displacement_final.bmp (3.2 MB)

#25

With snap

1
11920×1080 951 KB