RGDATA

        [GREG2\]RGDATA [Name|Array_X Array_Y Array_Z] [/SUBSET  NXmin  NYmin
    NXmax  NYmax]  [/VARIABLE]  [/FORMAT  Fmt [code]] [/INCREMENT IncX IncY]
    [/BLANKING Bval]

    This command optionally creates, then loads a two-dimensional  map  into
    the  Regular  Grid array (to be contoured by RGMAP, plotted by PLOT...).
    This is THE basic command needed for subsequent 2-dimensional treatment.
    "Regular Grid" means that data is internally stored as a two-dimensional
    array, thus lies on a Regularly sampled Grid. The  user-provided  "pixel
    values"  may  come from various "descriptions" of such regularly sampled
    (but possibly uncompletely sampled) data:
       1) Three 1-dimensional arrays, say, X Y and Z, that contain  Z=f(X,Y)
        at regular intervals in X and Y.
       2) A preexisting internal 2-D array (possibly a section of a 3D or 4D
        array).
       3) An external, specially formatted, file.
    For data NOT REGULARLY ("randomly") sampled,  use  the  GREG2\RANDOM_MAP
    command instead. The Regular Grid buffer can be saved in a file with the
    command GREG2\WRITE.

    Once defined, the Regular Grid description and data are available  under
    the SIC variables:
      - RG: the data array e.g. RG[1,1]
      - RG%NX: dimension along X
      - RG%XREF, RG%XVAL, RG%XINC: X axis conversion
      - RG%NY: dimension along Y
      - RG%YREF, RG%YVAL, RG%YINC: Y axis conversion
      - RG%MIN, RG%XMIN, RG%YMIN: minimum value and position
      - RG%MAX, RG%XMAX, RG%YMAX: maximum value and position

    The  following  command  syntax is used to deduce which "description" is
    provided:

      - With 0 or 3 arguments, RGDATA will try to assemble  Z=f(X,Y)  either
        from  the  X,Y  and  Z arrays (as defined by command COLUMN) or from
        "Array_X Array_Y Array_Z", that should be 1D SIC variables previous-
        ly  created. The option /INCREMENT is used to force the X and Y sam-
        pling interval to (IncX,IncY) in case of roundoff  errors.  Defining
        twice  the  same pixel is an error. If a blanking value is currently
        defined, non-sampled pixels will be attributed this value, which  is
        overriden by the Bval value of the /BLANKING option. Note that, if a
        blanking value is currently defined, pixels for which X or Y are  in
        the blanking range are themselves blanked.

      - With ONE argument (Name) following the command, Name is taken as the
        name of an existing SIC 2D variable if option /VARIABLE is  present.
        Otherwise,  Name  is  a  specially  formatted  file  (see HELP RGDA-
        TA FILE_FORMAT) from which the Regular Grid array must be read in.

    A rectangular subset of the array defined by the  pixel  coordinates  of
    the  Bottom  Left  Corner and Top Right Corner can be selected thanks to
    the /SUBSET option.