sarproz-group

DEM correction

This topic contains 1 reply, has 2 voices, and was last updated by  periz 2 years, 1 month ago.

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  • #838

    espiritocz
    Participant

    Hi,

    I use external DEM but it is shifted. I found out the correction coefficients in WGS-84 (shift is cca 0.025°N and -0.1°E) and used them to correct the Corner Lat/Lon boxes in “External DEM selection”.
    After this change I have remade External DEM and synthetic amplitude in SAR coordinates. But nothing changed. The obvious shift is still present.
    I tried GCP selection and done opposite – added the shift coefficients (-0.025N and +0.1E) to the GCP to make it towards the DEM. Written, pressed OK, again redone External DEM…. but nothing changed with the Image w.r.t. DEM.
    How can I manually shift the DEM?
    Note that applying “Auto GCP Through Ext. DEM” doesn’t work for me – it ends up with an error that i send attached.
    Thank you for any advices.

    Milan

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  • #843

    periz
    Keymaster

    Hi Milan,

    the key question is: in which format is your DEM?
    if it’s geotiff, nothing to do (unless you find the way to re-write the geotiff).
    The sw reads the fill-in boxes only if you are loading a matrix in gamma-format (read the manual).
    In that case, changing the lat-lon coordinates has the wished effect.

    To understand the error message you sent, I’d need to look into your data.
    It seems that the DEM is not fully covering your data.
    d

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