Problems for S1-A coherence estimation

recently I worked on a simple approach for interferogram generation. i tried the traditional steps on 1 pair of images that are large (4.23Gb each image). i got results as shown below:

it worth mentioning that the area i am studying should not show a changes since the time difference between the two images is 6 days i.e. there is no landslide within this period.
i dont know what i should get as an interferogram (if the purple image is correct in my case or not).
moreover, i don’t know why i am not getting a coherence estimation with information.
any help please?

Note: the first image corresponds to the elevation, and i subtracted the topographic phase during interferogram generation.

a purple interferogram indicates that the coregistration failed (no slave image information).

Did you follow these steps?
Sentinel-1 TOPS interferometry

Some remarks:

  • Even if there is no surface change, coherence can be low because of temporal decorrelation.
  • As you mention the file size: Did you see that you can reduce the amount of bursts in the TOPS Split module?
  • Which DEM did you use during the BackGeocoding?
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i was using the first version of the tutorial so i missed some steps. i will read this one, thank you so much.
after that i will check the results.

is this first version still around somewhere?

yes i found it on the internet

Please share the link - we are currently trying to remove outdated tutorials from the web.

thank you. We removed the old tutorials from the server.

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