next up previous contents index
Next: RGDATA FILE_FORMAT Up: GREG2 Language Internal Help Previous: RESAMPLE   Contents   Index


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 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.  RGDATA al-
    locates virtual memory according to the map size, so that  there  is  no
    limit on the array dimensions.


Subsections

Gildas manager 2011-09-07