I’m interested to do the process of land subsidence and displacement analysis using SENTINEL 1 data.which type of data( like which modes,polarization,sensing mode) can be use to execute the process and how the process can be do for the analysis
many thanks in advance.
you need SLC products for this, one polarization (preferably VV) is sufficient.
The steps to generate an interferogram are described in this tutorial: http://step.esa.int/docs/tutorials/S1TBX%20TOPSAR%20Interferometry%20with%20Sentinel-1%20Tutorial.pdf
To convert it to absolute phase changes, the interferogram must be unwrapped.
Unwrapping itself is demonstrated here: SNAPHU Unwrapping
Then you import the unwrapped phase back into SNAP (described here: Problem in Snaphu Import section)
Lastly, you perform “phase to displacement” to get the change along the line of sight.
Thank you for the comprehensive reply. I have greatly benefited from it.
But I need to take some steps further, which I am not very clear with at the moment. I want to monitor subsidence for over a period of 4 years. Please, what further steps can I take to achieve this goal.
Have you seen this topic? Subsidence map in 3d view
Yes! But to my understanding there was place where interferogram stacking, or historical subsidence monitoring techniques was mentioned. I look forward to further supports.
a suggestion on how to combine the deformations of several image pairs is made in this tutorial:
But note that this was created using NEST and some of the steps (unwrapping, phase to deformation) are now easier to achieve.