comma-never-coma
commented
1 year ago A clear explanation was given by @EJFielding from https://forum.step.esa.int/t/long-processing-time-for-phase-unwrapping-snaphu/35306/5
The amount of memory that SNAPHU requires to run depends on the number of pixels in each tile. If you are trying to unwrap an interferogram without any multilooking, then you will have much larger images. If your SNAPHU program is using a large percentage of the memory on your computer, it may run very slowly even if it does not get an “out of memory” error.
As mentioned above, I recommend to apply larger range looks and azimuth looks, such as "10:2" or "20:4". Otherwise you have to make sure that computer memory is sufficient.
InSAR2023
Functions to be executed: ['Function-1'] Running: unwrap ['--ifg', '/media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.int', '--unw', '/media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.unw', '--coh', '/media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.cor', '--reference', '/media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/reference', '--defomax', '2', '--rlks', '4', '--alks', '1', '--method', 'snaphu'] unwrapping method : snaphu
snaphu v1.4.2 Reading wrapped phase from file /media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.int No weight file specified. Assuming uniform weights Reading correlation data from file /media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.cor Calculating smooth-solution cost parameters Initializing flows with MCF algorithm Integrating phase Writing output to file /media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.unw Growing connected components on second pass
snaphu v1.4.2 Reading unwrapped phase from file /media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.unw No weight file specified. Assuming uniform weights Reading correlation data from file /media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.cor Calculating smooth-solution cost parameters Growing connected component mask Writing connected components to file /media/insar/53bb474c-9882-4dbd-a577-cfaa886beb00/NewZealand/merged/interferograms/20220101_20220125/filt_fine.unw.conncomp time used: 155 mins 3.7 secs.