PLOT IMAGE_HOWTO
Keywords: greg

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PLOT IMAGE_HOWTO

        There exist a number of ways to get pixels into GREG2\:
          - Read the X, Y, Z values of a Z=f(X,Y) "image", use RGDATA (if X  and
            Y define a regularly sampled grid) or RANDOM (if X and Y are "random
            points")  to  make  a  Regular  Grid  Map  (see  HELP  GREG1\COLUMN,
            GREG2\RGDATA and GREG2\RANDOM)
          - Read a RGDATA-format file with the RGDATA command (see topic RGDATA)
          - Define  a 2-D SIC variable and fill it with values, or connect a SIC
            variable with an  existing  GILDAS  DATA  FORMAT  (GDF)  image  (see
            HELP SIC\DEFINE),  or  use  the  SIC\ACCEPT  command to read format-
            ted/unformatted streams of values and put them in a SIC 2-D variable
            (see  HELP SIC\ACCEPT).  Then give this 2-D variable to the internal
            image buffer by the RGDATA Varname /VARIABLE command.
          - The command GREG3\IMAGE connects directly an existing 2,  3  or  4-D
            GILDAS   DATA   FORMAT   image   in   the  GREG  image  buffer.  See
            HELP GREG3\IMAGE for details.

        FITS files can also be loaded in Greg:
          - Use the VECTOR\FITS command to convert a FITS image to a GDF (Gildas
            Data Format) image that will be directly readable afterwards.
          - "on-the-fly"  automatic  conversion  from  FITS  to  GDF  format for
            GREG3\IMAGE command.
          - avoid disk-to-disk conversion by loading the FITS directly in memory
            with the command SIC\DEFINE IMAGE.
        See each command HELP for details.