SNAPHU UNWRAPPING Unexpected or abnormal

Hi fellows, I have been trying to unwrap my interferogram using the command line, but the result always says “Unexpected or abnormal exit of child process.”

At first, I used the VV polarization, but it resulted in an error. Then I used the VH polarization, but the result was still an error.

this is my interferogram:

I have been trying really hard to find a solution for this. If anyone could help

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The interferogram is almost pure noise (low coherence). One cannot unwrap noise and if unwrapping works, the result is nonsense.

Thank you @mengdahl for your response. I understand that the interferogram is almost pure noise (low coherence), and that one cannot unwrap noise, making any result from unwrapping nonsense.

Given this situation, could you please advise on the following:

  1. How can I improve the coherence of my interferogram to make it suitable for unwrapping?
  2. Are there specific preprocessing steps or parameters I should focus on to enhance the quality of the data?

Start with the lowest possible temporal baseline (6/12-days) when selecting your data, and mask out areas with low coherence.

Thank you for your earlier advice about starting with the lowest possible temporal baseline and masking out areas with low coherence. Now I understand this approach for improving coherence.

However, I am interested in obtaining annual deformation data, so I need to use yearly data. Are there any methods or techniques that can help improve coherence and make unwrapping feasible when working with longer temporal baselines, such as annual data?

Thank you for your assistance.

Longer-wavelength L-band data would help, if it is available. At C-band you will need to work with stacks of short temporal baseline interferograms. Look into SBAS and PSI InSAR-processing techniques.

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Thank you, I will try out this advice and will let you know about the results later.

is it posible to do SBAS and PSI InSAR on snap?

SNAP can do the data stack preparation and supports the use of external tools like StaMPS and PyRate for PSI & SBAS processing.

Note: This is very advanced data processing with a steep learning curve - you should start working with single interferograms like you did in your original post in order to start understanding what InSAR processing is. There are no turnkey-solutions (insert data, get useful results automatically) in this field.