Snaphu Export

Does anyone can help me that after I have run Snaphu export, there are eight files, include UnwPhase_ifg_srp_VV_25Jul2015_18Aug2015.snaphu.hdr, but there is not .img file. ???

Img file will be generated by Snaphu in the process of unwrapping of your phase that is stored in Phase_ifg_srp_VV_25Jul2015_18Aug2015.snaphu.img

Thank you, that why I can not find the img file name with header UnwPhase.

Besause the Snaphu export operator only prepares the data for the unwrapping procedure. The actual unwrapping still has to performed by an additional program that runs under Linux.

For more information read the file http://sentinel1.s3.amazonaws.com/docs/S1TBX%20Stripmap%20Interferometry%20with%20Sentinel-1%20Tutorial.pdf, especially sections Phase Unwrapping and Unwrapping with SNAPHU.

Hey,
I am trying to create an interferogram between two images from S-1 (S1A_IW_SLC__1SDV_20150509T052537_20150509T052604_005840_007841_A36E and S1A_IW_SLC__1SDV_20151105T052545_20151105T052612_008465_00BF7A_59D1)

  • using the SNAP 2 toolbox on a 64 GB RAM system with a 64 bit Windows OS.
  • everything runs smoothly until the snaphu export step (coreg–>ifg–>deburst–>topophase–>goldstein filt–>snaphu export)
  • I get a .img and hdr file for the export.
  • But when I run the snaphu unwrapping on my Ubuntu VM, I get the following error:

root@root-VirtualBox:$ snaphu -f snaphu.conf Phase_ifg_srp_IW1_VV_09May2015_05Nov2015.snaphu.img 72626

snaphu v1.4.2
27 parameters input from file snaphu.conf (84 lines total)
extra data in file Phase_ifg_srp_IW1_VV_09May2015_05Nov2015.snaphu.img (bad linelength?)

—Any idea what that means? I’ve unwrapped before using the same VM and with Snap 1.0 and though it took long, it worked. This is the first time I get an error like this. Could it have something to do with the Snap 2 toolbox?
I had a look at the conf file of this particular image, and of previous snaphu.conf files that were successfully unwrapped, and the only difference I can see is with the naming convention of the file. The other files were named with srd instead of : Phase_ifg_srp_IW1_VV_09May2015_05Nov2015.snaphu.img as it is in my present image

I do not see why that would pose a problem, but still, just something I noticed.

I tried the snaphu unwrap on one of the snaphu exports of a previously created image and it works. So the problem isnt with the VM.
Any smart ideas?

Thanks a tonne,
Gopika

SRP (Subtract Reference Phase) is after producing the interferogram and
you have subtracted the phase Earth phase.
SRD (Subtract Reference DEM) is after topographic phase removal.

The band dimensions should be the same either way. I think the bad
linelength error may be related to passing snaphu a wrong dimension.
Double check that the snaphu command in teh snaphu.conf file corresponds
to this product and the dimensions are the same as the band.

Dear Luis,
I’m facing the same problem I checked the dimension from metadata and snaphu.conf file. and they are same. So would you please to find out the reason of this error.

Dear Gopika,

Did you get any solution for this issue, “snaphu v1.4.2
27 parameters input from file snaphu.conf (84 lines total)”

Falah,

I did have similar issues with this and on another forum found that the segmentation fault is likely due to the log file created by SNAPHU. In the snaphu.conf file comment out the log file line with a # and that should fix the problem

Dear Peter and jegrix
I have same problem like peter and there is not img file for UnwPhase.
Look at this:


and when I want to import in SNAPHU, there is below error:

did snaphu give you any error? Based on your first image it looks like it didn’t even start.

I forgot to do one step. Now it is working. Thanks:slight_smile:

I got an error file while unwrapping using snaphu which says

snaphu v1.4.2

Log file generated Tue Mar 21 05:09:28 2017

Current working directory: /cygdrive/c/Temp/snaphu-v1.4.2/bin/subset_S1A_IW_SLC__1SSV_20150417T001852_201505123T001851_005516_0070C1_460B_Orb_IW1_ifg_Deburst_dinsar_flt.data/subset_S1A_IW_SLC__1SSV_20150417T001852_201505123T001851_005516_0070C1_460B_Orb_IW1_ifg_Deburst_dinsar_flt

Command line call: snaphu -f snaphu.conf Phase_ifg_srd_IW1_VV_17Apr2015_23May2015.snaphu.img 2836

File input and output and runtime options

INFILE Phase_ifg_srd_IW1_VV_17Apr2015_23May2015.snaphu.img
LINELENGTH 2836
OUTFILE UnwPhase_ifg_srd_IW1_VV_17Apr2015_23May2015.snaphu.img

Empty value for parameter WEIGHTFILE

Empty value for parameter AMPFILE

Empty value for parameter MAGFILE

CORRFILE coh_IW1_VV_17Apr2015_23May2015.snaphu.img

Empty value for parameter ESTIMATEFILE

Empty value for parameter COSTINFILE

Empty value for parameter COSTOUTFILE

LOGFILE snaphu.log
STATCOSTMODE DEFO
INITONLY FALSE
UNWRAPPED_IN FALSE
DEBUG FALSE
INITMETHOD MCF
VERBOSE TRUE

File Formats

INFILEFORMAT FLOAT_DATA
OUTFILEFORMAT FLOAT_DATA
AMPFILEFORMAT ALT_SAMPLE_DATA
MAGFILEFORMAT FLOAT_DATA
CORRFILEFORMAT FLOAT_DATA
ESTFILEFORMAT ALT_LINE_DATA
UNWRAPPEDINFILEFORMAT ALT_LINE_DATA

SAR and Geometry Parameters

ALTITUDE 698933.20600000

ORBITRADIUS 7072478.31100000

EARTHRADIUS 6373545.10500000
BASELINE 19.43100000
BASELINEANGLE_DEG 174.80942329
TRANSMITMODE REPEATPASS
NEARRANGE 822569.55954450
DR 2.32956210
DA 15.61455090
RANGERES 2653030.60171610
AZRES 81.99448870
LAMBDA 0.05546580
NLOOKSRANGE 1
NLOOKSAZ 5
NLOOKSOTHER 1
NCORRLOOKS 23.80000000
NCORRLOOKSRANGE 3
NCORRLOOKSAZ 15

Scattering model parameters

KDS 0.02000000
SPECULAREXP 8.00000000
DZRCRITFACTOR 2.00000000
SHADOW FALSE
DZEIMIN -4.00000000
LAYWIDTH 16
LAYMINEI 1.25000000
SLOPERATIOFACTOR 1.18000000
SIGSQEI 100.00000000

Decorrelation model parameters

DRHO 0.00500000
RHOSCONST1 1.30000000
RHOSCONST2 0.14000000
CSTD1 0.40000000
CSTD2 0.35000000
CSTD3 0.06000000
DEFAULTCORR 0.01000000
RHOMINFACTOR 1.30000000

PDF model parameters

DZLAYPEAK -2.00000000
AZDZFACTOR 0.99000000
DZEIFACTOR 4.00000000
DZEIWEIGHT 0.50000000
DZLAYFACTOR 1.00000000
LAYCONST 0.90000000
LAYFALLOFFCONST 2.00000000
SIGSQSHORTMIN 1
SIGSQLAYFACTOR 0.10000000

Deformation mode parameters

DEFOAZDZFACTOR 1.00000000
DEFOTHRESHFACTOR 1.20000000
DEFOMAX_CYCLE 1.20000000
SIGSQCORR 0.05000000
DEFOCONST 0.90000000

Algorithm parameters

INITMAXFLOW 9999
ARCMAXFLOWCONST 3
MAXFLOW 4
KROWEI 65
KCOLEI 257
KPARDPSI 7
KPERPDPSI 7
THRESHOLD 0.00100000
INITDZR 2048.00000000
INITDZSTEP 100.00000000
MAXCOST 1000.00000000
COSTSCALE 100.00000000
COSTSCALEAMBIGHT 80.00000000
DNOMINCANGLE 0.01000000
NSHORTCYCLE 200
MAXNEWNODECONST 0.00080000
MAXNFLOWCYCLES 1
SOURCEMODE 0
CS2SCALEFACTOR 8

File names for dumping intermediate arrays

Empty value for parameter INITFILE

Empty value for parameter FLOWFILE

Empty value for parameter EIFILE

Empty value for parameter ROWCOSTFILE

Empty value for parameter COLCOSTFILE

Empty value for parameter MSTROWCOSTFILE

Empty value for parameter MSTCOLCOSTFILE

Empty value for parameter MSTCOSTSFILE

Empty value for parameter RAWCORRDUMPFILE

Empty value for parameter CORRDUMPFILE

Piece extraction parameters

Parameters ignored because of tile mode

PIECEFIRSTROW 1

PIECEFIRSTCOL 1

PIECENROW 0

PIECENCOL 0

Tile control

NTILEROW 10
NTILECOL 10
ROWOVRLP 0
COLOVRLP 0
NPROC 4
TILECOSTTHRESH 500
MINREGIONSIZE 100
TILEEDGEWEIGHT 2.50000000
SCNDRYARCFLOWMAX 8
RMTMPTILE FALSE
ASSEMBLEONLY FALSE

Connected component control

Empty value for parameter CONNCOMPFILE

REGROWCONNCOMPS FALSE
MINCONNCOMPFRAC 0.01000000
CONNCOMPTHRESH 300
MAXNCOMPS 32

also i got a file created without any extension


please help

Hi Dear,
Which step you had missed last time?? The error is same for me, so can you please write the steps for me. I am following steps as… Coregistration (TopSarSplit, AppOrbitFile, BackGeocoding) >> EAP Phase correction >> Interferogram Formation >> Top Debrust >> Topographic Phase Removal >> Goldstein Phase Filtering >> Snaphu Export (Did not generated Img file for Unwphase ) >> Snaphu Import (Not working).
Thank you in advance…!!

Hi There,
If I run it from Ubuntu Konsole then I have this ERROR:

compName:~/S1_test/Snap_Export/S1A_IW_SLC__1SDV_Orb_Stack_pc_Ifg_Deb_DInSAR_Flt$ sudo snaphu -f Phase_VV_05Dec2014_05Apr2017.snaphu.img 1721
[sudo] password for compName:

snaphu v1.4.2
unrecognized configuration parameter ‘s��r�?Y��?���?|����’ (Phase_VV_05Dec2014_05Apr2017.snaphu.img:5666)

Can anyone please help to correct me.
Thanks

Thank you…

amylauraparker - May '16
“I did have similar issues with this and on another forum found that the segmentation fault is likely due to the log file created by SNAPHU. In the snaphu.conf file comment out the log file line with a # and that should fix the problem”

#LOGFILE… in the snaphu.conf file is the solution. Now it is running. Great… Thanks again.
Have fun

Are u using a manual for doing SNAPHU or not?

Hi, Thanks for your response. I am using these tutorials:

http://sentinel1.s3.amazonaws.com/docs/S1TBX%20TOPSAR%20Interferometry%20with%20Sentinel-1%20Tutorial.pdf
http://sentinel1.s3.amazonaws.com/docs/S1TBX%20Stripmap%20Interferometry%20with%20Sentinel-1%20Tutorial.pdf
http://corp.array.ca/nest-web/help/operators/SnaphuExportOp.html
https://web.stanford.edu/group/radar/softwareandlinks/sw/snaphu/snaphu_man1.html
http://vldb.gsi.go.jp/sokuchi/sar/qanda/qanda-e.html#q2-8

AND the Step Forum + some books…
I would be so happy if you could suggest us something more interesting.
Cheers

Can anyone comment on the output. Am I correctly generated results or the visual expression giving any bad indication ??

hi, im following stripmap tutorial and im facing problem to unwrapping phase using snaphu in virtual linux. i did the step but when i checked the folder, there is no /vmshare/data/target_sanphu/ only /mnt/hgfs/ in file system. then i cant run the snaphu.conf even i made gedit snaphu.conf & in my /home/sar/ and copy paste the command to call snaphu