sarproz-group

Using external DEM source coregistration

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    • #5933
      yvhout
      Participant

      Hi,

      I want to use an external DEM, and I selected it at the DEM source at coregistration parameters, but when I try to run coregistration I get the error I listed below this message.
      I have tried 2 DEM .tif files:
      – High Mountain Asia from NSIDC
      – AW3D30 from JAXA
      and they definitely cover the selected area.

      Coordinates System:
      Horizontal Coordinates: WGS 1984 [EPSG: 4326]
      Vertical Coordinates: WGS84 (EGM96 GEOID)

      I want to use a different DEM than the provided SRTM as I want more current data as I am researching from 2015-2021 (and a DEM more suitable for the Himalayas where the choice of DEM can have a big influence I believe).

      What am I doing wrong? (everything does work when using the default SRTM)
      Thanks in advance!

      MATLAB MESSAGE:

      Slave images coregistration

      get_master_pts: previous files available. Exiting.

      Coregistration Mode: Automatic (Cross-Correlation for Restituted Orbits and Only Orbits for Precise ones)

      Initial Offset: Orbits

      Amplitude Cross-Correlation:
      Keeping existing files -if available- (to overwrite them, select the Overwrite option in Coregistration Parameters)
      Reference Window 64, 64
      Pixel Search 12, 12
      Correlation OVS 64, Win 16
      Thresholds: Corr. 0.3, SNR 7

      Points Skimming:
      Using the External DEM
      Polynomial degree: 1
      Thresholds: Nsig 1.5, MaxRms 0.05, MinPts 50

      Resampling coefficients:
      Using the External DEM
      Polynomial degree: 1

      Coregistration (Only Orbits) between images 20180712_VV and 20141025_VV

      SAR2xyz: NaNs detected in Height, aborting!!!!

      SAR2xyz: NaNs detected in Height, aborting!!!!

    • #5935
      periz
      Keymaster

      Hi,
      generally speaking, read carefully this: https://sarproz.com/manual/Sarproz_errors_management.html
      In your case, given this message: “get_master_pts: previous files available. Exiting. ”
      start over the whole process again (don’t update the site, re-extract the master image)
      best

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