I have been trying to unwrap my interferogram using the SNAPHU-unwrapping plugin and I’m getting the following error.
Is this a tool error ? or a file error?
Note: My system is equipped with a 16 GB RAM.
a tool error. I had this a couple of times as well and was able to solve it by changing the number of tiles.
I see you use 20x20 tiles which is a bit much. Try 15x15 and make sure you increase the overlap as well. Please have a look at EJFielding’s comment on this: SNAPHU parameters
I tried with those parameters, 12x12 tiles and an overlap of 200. Still facing the following error:
did you delete the tiles folder before running again? Sometimes, the temporary files prevent the execution of a new run.
I also suggest trying MST instead of MCF (or vice versa) and if this does not change anything, also SMOOTH instead of TOPO/DEFO.
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I am trying to unwrap a single subswath, so what would be the ideal parameters? The default tiles are 10x10 and 0 overlap. As the previous links suggest, there should be some amount of overlap. How do you determine these parameters.
When you know the total size of your raster you can calculate how much tile rows and lines you need so that they at least fall below 3000 pixels.
200 overlap is fine, independently of tile size.
I calculated the number of rows and lines according to the raster size. Encountered the following error during SNAPHU unwrapping:
snaphu v1.4.2
27 parameters input from file snaphu.conf (84 lines total)
Logging run-time parameters to file snaphu.log
Creating temporary directory snaphu_tiles_12560
Unwrapping tile at row 0, column 0 (pid 14776)
Unwrapping tile at row 0, column 1 (pid 6168)
Unwrapping tile at row 0, column 2 (pid 16824)
Unwrapping tile at row 0, column 3 (pid 2868)
Unwrapping tile at row 0, column 4 (pid 9420)
Unwrapping tile at row 1, column 0 (pid 6132)
Unwrapping tile at row 1, column 1 (pid 7708)
Unwrapping tile at row 1, column 2 (pid 12548)
Unwrapping tile at row 1, column 3 (pid 4640)
Unwrapping tile at row 1, column 4 (pid 12252)
3 [main] snaphu 12560 cygwin_exception::open_stackdumpfile: Dumping stack trace to snaphu.exe.stackdump
Process exited with value 35584
Finished tool execution in 3837 seconds
what mode did you select? TOPO, DEFO or SMOOTH?
Try SMOOTH an see if the error persists.
I had selected TOPO mode.
Changed it to SMOOTH. Still encountering the same error.
snaphu v1.4.2
27 parameters input from file snaphu.conf (84 lines total)
Logging run-time parameters to file snaphu.log
Creating temporary directory snaphu_tiles_1260
Unwrapping tile at row 0, column 0 (pid 11304)
Unwrapping tile at row 0, column 1 (pid 18528)
Unwrapping tile at row 0, column 2 (pid 2716)
Unwrapping tile at row 0, column 3 (pid 17424)
Unwrapping tile at row 0, column 4 (pid 18268)
Unwrapping tile at row 1, column 0 (pid 15064)
Unwrapping tile at row 1, column 1 (pid 1456)
Unwrapping tile at row 1, column 2 (pid 4876)
Unwrapping tile at row 1, column 3 (pid 18728)
Unwrapping tile at row 1, column 4 (pid 16456)
1 [main] snaphu 1260 cygwin_exception::open_stackdumpfile: Dumping stack trace to snaphu.exe.stackdump
Process exited with value 35584
Finished tool execution in 3498 seconds
how much overlap did you apply between the tiles?
I applied an overlap of 200
that is a reasonable value. Could it be that the path where you execute snaphu contains special characters or spaces?
Try to move your data (and snaphu.exe) to C:\temp\ for example, and run it there.
I have tried giving different target folders. But the unwrapping outputs always end up in C:\Users*username*
C:\Users\GEO That’s my target folder… Don’t think there are any special characters here
and in the path where snaphu.exe or the S1 data is located?
I wonder how you define a target folder for the unwrapping at all? Usually the product is simply created in the same folder as the unw_phase_[…].hdr file
I have done both 1)specified it in the same folder as the input phase.img and 2) not specified an output folder in processing parameters tab, but the output files get created in C:/Users/. I have tried reinstalling snap as well. I’ve tried it on a different machine and this error did not occur there. What could be the source of this error?
where is snaphu.exe located?
Maybe one of the environment variables of your first system somehow defines C:\Users\ as the temporary scratch layer. But I have never heard of this issue before, to be honest.
in one of your screenshots above I noticed that you are using cygwin?
I am not using cygwin, that was the execution output from processing parameters tab.