Ok, and by ‘will not be exported’, do you mean that neither the snap2stamps script nor the SNAP GUI will begin the export process? Or will they just run indefinitely?
It’s strange because the coreg and ifg images for the first AOI (processed using snap2stamps) seem correct (I just can’t seem to export them).
Can the snap2stamps scripts be modified to use SRTM 1Sec?
I’ve just tried both SRTM 1Sec HGT and Grid in TOPS+ESD Coregistration, and neither seems to work (I get the same “java.lang.NullPointerException” error).
Is it coreg_ifg2run, coreg_ifg_computation, or coreg_ifg_computation_subset that I would need to edit? Although currently I already see SRTM 1Sec in all of these (the following image is from coreg_ifg2run.xml):
Following a downgrade from Ubuntu 20.04 to 18.04 LTS, upgrading RAM to 32 gb, and using SNAP v6, snap2stamps has been fully executed.
After running mt_prep_snap, however, I received an initial message after the opener, “matlab: permission denied,” and then the process continued- it’s still underway, but amplitude estimates have now been produced for all 114 images, as have their interferograms. Does that message indicate the results will be erroneous?
No actual error messages have appeared yet (3/9 patches processed). I went ahead and changed the matlab installation folder contents’ permissions to read/write, hopefully that doesn’t mess something up!
This only means that you do not have matlab in the environmental variables which can be found from mt_prep_snap and a starting file will not be created.
However, this can be created within MATLAB while running stamps itself.
TRAIN cannot be applied to snap2stamps.
TRAIN is applied together with StaMPS processing, not to snap2stamps. Please do not mixed terms,
TRAIN does not estimate only APS for the master image. I believe you are confused.
Please read TRAIN manual and tutorial so that you will see that TRAIN estimates APS for each of the images, and the different options for it.
After I run the python coreg_ifg_topsar py project.conf scripts, my interfergrams are very noisy and has low coherence. What ideas do you have for improving their coherence?In addition, my study area does not have Sentinel-B images.
This is okay (to a certain degree), because PS InSAR will throw away most of the pixels and only continue with those with a stable phase information. Please have a look at these slides which compare a traditional interferogram with PS InSAR phase analysis: Persistent Scatterer InSAR and StaMPS
Coherence cannot be increased technically, it all depends on the amount of vegetation and other surfaces which cause decorrelation.
i’d say so, yes. Most of the interferograms show the same pattern which indicates that the remaining PS are largely free of noise. The interferograms which strongly differ from the rest are probably affected by atmospheric phase contributions, but as long as these are not imposing wrong patterns in the overall result, it should be fine. You can also identify outliers in the time series plots quite well.