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 is itself a 2D SIC variable under the
    name "RG". Once loaded, the RG can be saved on a file with  the  command
    GREG2\WRITE.

    The following command syntax is used to deduce  which  "description"  is
    provided:
      - Without arguments following the command, or with 3 arguments, RGDATA
        will  try  to assemble Z=f(X,Y) either form 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 previously created by command SIC\DEFINE.
        The option /INCREMENT is used to force the X and Y sampling interval
        to  (IncX,IncY)  in  case of roundoff errors. 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  RGDATA
        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.  RGDATA
    allocates virtual memory according to the map size, so that there is  no
    limit  on the array dimensions. Beware however that handling maps larger
    than 512 by 512 pixels may be slow...