1 BLANKING Change the blanking value of a GDF file
        BLANKING

    Modify the blanking value of a GDF file. This operation has 2 purposes:
    1  -  modify  the  blanked  data to a new blanking value, and modify the
    header consistently. This means  all  the  blanked  data  and  only  the
    blanked data in the input file will be blanked in the output file.
    2 - patch NaN values to replace them by the blanking value. This is use-
    ful when importing external data, as  NaN  values  not  ignored  by  all
    Gildas commands.

    Note  that  this  operation  cannot  be done through the HEADER program,
    which only modifies the blanking value of the header but not the  corre-
    sponding data (e.g. blanked data could become unblanked by doing this).

2 Y_NAME$
        TASK\FILE "Input file name" Y_NAME$

    The name of the input image (with old blanking value)
2 X_NAME$
        TASK\FILE "Output file name" X_NAME$

    The name of the output file (with modified blanking value)
2 BLANKING$
        TASK\REAL "New blanking value" BLANKING$

    This is the new blanking value
2 TOLERANCE$
        TASK\REAL "New tolerance on blanking" TOLERANCE$

    This is the new tolerance on blanking.
1 ENDOFHELP


































