Hello,
I’m trying to coregister a stack of 8 S1 GRD images using SNAP v10.0.0 in Ubuntu 22.04.
Images have been preprocessed with calibration, subset and terrain correction. They are all ascending and on the same area.
Depending on the image I choose as master, I get
the master and slave 1 bands empty and the other slaves ok
OR
the processing hangs at some point while cross correlating one slave, with zero CPU usage and need to cancel and close SNAP to actually stop (the “Cancel” button just stops the slide bar but processing keeps going in background…)
No errors whatsoever.
I had a similar problem with other 8 images of the same area but changing the master at some point it worked.
Notably, I tried also coregistering only 4 images and again got the first two bands empty.
Any clues about what’s happening? Is there any mean to check what’s wrong?
I also encounter this problem in SLC coregistration. It happens only at first slave bane. I have complained about this before but no feedback from the community just like nobody has this problem. However, I have tried this on 10s computers with both Linux and Windows system, and all of them have this problem.
My temporary solution is to do coregistration using only two images, in this condition, the slave band will write out correctly. You can copy the band file in .data folder to replace the incorrect one in your old dim product.
We still need developers to look at this problem, I hope they will notice.
A figure of empty band:
left upper row: intensity of master
right upper row: real band (i) of slave 1
left lower row: intensity of slave 1
right lower row: image band (q) of slave 1
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For my time-series of 7 S-1 SLC files, I tried with the generic coregistration command and now I’m getting:
Index -1 out of bounds for length 3
I’m using Bilinear Interpolation, orbit as the initial offset method and Minimum as the output extents in the CreateStack tab.
I’ve tested it with just two images and no problem. As soon as I start adding more scenes I get errors, even keeping the same options. With 3 scenes I get this:
“The specified region, if not null, must intersect with the image’s bounds”.
Here’s where my 7 scenes are, to make sure you’re not about to ask me if they overlap:
Please don’t use generic co-registration with S-1 SLC TOPS data. Are the related tutorials difficult to identify or how come you decided to use generic coregistration?
I had so many problems with S-1 SLC TOPS back geocoding that I used generic coregistration. I’m now using back geocoding: with just two images, I’m getting the master image right, but the slave image is only made of NaN.
You should use S-1 TOPS co-registration as it is the tailored method for TOPS data. If the recommended processing graphs for co-registration do not work, your SNAP installation must be corrupted. We have many thousands of users and S-1 InSAR is a common operation, so we would already know if this was a problem with SNAP.
