MAP_POLAR /COMPUTE

        [ADVANCED\]MAP_POLAR GenericBegin [GenericEnd] [/COMPUTE [Threshold]]

    Compute  the  Polarization Fraction image 'GenericBegin'"-P"'.Type', and the
    Polarization Angle image 'GenericBegin'"-A"'GenericEnd" from  the  'Generic-
    Name'"-K"'GenericEnd'  images  where  -K is all of the -I, -Q, and -U Stokes
    images.

    The derivation is only made on pixels that are brighter than Threshold sigma
    in the Stokes I image. The use of the /COMPUTE option reset  all  parameters
    that control further display to their default values.