Mintpy cannot create time series because ISCE is nor creating interferograms.

[Carolina Hurtado]

Hello Mintpy community,

I know this is more an ISCE2 question, but I am sharing this here in case someone knows the answer. I posted it in the ISCE2 github website as well. 

I processed a stack of interferograms two times with data from Sentinel-1A.
The first stack included ~201 images, including one from 2015. The second stack has the same dataset but I did not used the image from 2015 (so ~200 images). I processed the time series using Mintpy and for the first case, it creates a decent time series, but for the second case, it creates an empty time series with only data for the reference point (all the displacement is 0).

I went over the processing, and I noticed that the merged/interferograms folder for each case has different contents for interferograms with the same dates. Meaning that in the first case, ISCE2 created all (most) the interferograms in each folder (e.g., filt_fine (.unw, .unw.xml, .unw.vrt, .unw.conncomp.xml, .unw.conncomp.vrt, .unw.conncomp)) when running the step run_11_unwrap. But in the second case, it created the folders with just a few files. It never retuned an error.

I did not change anything in the configuration but the date of the reference date. In the first case, I used the date of the 2015 image, in the second case I used the date of the first image in 2016.

I thought that re-doing the stack was going to improve the final results as the interferograms created with the image from 2015 were the only ones not conneted to the time series. The network with the 2015 image is great, the networt without that image only has a few conections.

I am attaching a couple of screenshots showing the different files created for each case:

Example files in merge/interferograms/20160421-20160503 (in the stack with the 2015 image)

Example files in merge/interferograms/20160421-20160503 (in the stack without the 2015 image)

Any help is appreciated!

[Manudeo Singh]

I suspect that you have issue of number of burst in reference not matching with secondary SLCs. Check number of burst pairs in coreg_secondary and reference folders. If that’s the case, I recommend selecting 0.5 degrees extra in North and South directions from your AOI when you download the SLCs. 

Also, check the log of other steps, mostly 5-9 to see if they reported any errors (you can use grep to search for the ‘error’ in logs). 

One of the steps (I think 8) also checks if you have a full-rank matrix. See if that is not the case. Another step (11?) checks for burst matching and will tell you which dates have issues. Again, reading their logs will help you diagnose the problem. 

Let me know how it goes, I’m in field this week but will be available from next week and can look at my InSAR processing notes and recipes to help you better. 

Best

Manu

_________________________________
Dr Manudeo Singh
Royal Society - Newton International Fellow
Department of Geography & Earth Sciences
Aberystwyth University, Wales, UK

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[Carolina Hurtado]

Hello  Manudeo,

Thanks for your response! I checked the reference and coreg_secondarys folders. The reference folder have IW1 (burst 1 to 4) and IW2 (burst 1 to 3). But some images in the coreg_secondaries folder only had  (burst 2 to 4) and IW2 (burst 2 and 3), this occurred mostly for images adquired in 2016 and beggining of 2017. I decided to use only data starting on 2017 to play safe as it takes days to create the stack. I kept the same bbox because it was bigger than my AOI. 

I am running again the stack and will let you all know any news!

Best,

Carolina

[Carolina Hurtado]

Hi Menudeo,

I wanted to share some news. I ran the stack again, I got errors only on the step 10 "FileNotFoundError:[Errno 2] No No suc file of directory: 'merged/interferograms/20250116_20250221/fine.int'.xml", this error appears for almost all the interferograms. I believe these files are created in step 8, but it didn't, but it didn't report any error during that step.

Have you had this problem before?

Thanks,

Carolina