Absurd results of interferograms

Hi everybody,

I’m currently working on landslide and carrying out interferogram by performing following steps below but my results occur absurd and irrelevant.

-S1 TOPS Split
-Apply Orbit File
-Back Geocodding
-Interferogram Formation
-Tops Deburst
-Topographic Phase Removal
-Goldstein Filtering
-Phase to Displacement
-Range-Doppler Terrain Correction

What do you think the reason is? What may have caused this?

Did you apply ESD after the step of Back-Geocoding?

Did you read the entire of this thread,

Source of thread

Same in my case - InSAR in landslide monitoring Take a look at the first post. Wirh ESD applied.

Steps seem ok.

We still need more info to understand what could go wrong.

  1. Can you display the coherence image of the interferogram and its histogram ?
  2. What is the temporal baseline between the image ?
  3. Do you have a lot of forest in your region of interest ?
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First of all, thanks for all your responses. Here the things you want:

  1. 1
  2. Image acquisition dates are 19 february 2018 and 27 march 2018 respectively.
  3. Here is the google earth image of the study area

I added ESD but I unfortunately couldn’t get reasonable result from that.

Thanks for your response…

@hakan What I see is a forested area do know if for those dates there is any vegetation? Do you expect north-south movements?
It is also nice to provide the full scenes names.

From what I can see, the reference point is in a highly a vegetated area with low coherence. However, you can observe high coherence in the urbain area.

So you can probably study the displacement on the urbain area but probably not on the landslide zone. In addition I would suggest not to unwrap the phase on the whole scene but instead focus on regions with higher coherence. I never masked a region for unwrapping. It is probably very simple but I don’t really know how to proceed but maybe @ABraun knows how to do it.

@FeiLiu once suggested a work around that seems to do what you suggest: Is it the right way to create mask for phase unwrapping?

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That seems a interesting way to proceed.

It would be great in the SNAPHU export to add the possibility to add a “mask band”. @marpet Do you think it is possible in future releases of SNAP?

One more “whish-to-have” - usage of snaphu plugin in the graph processing chain.