1 Language
                            GREG3\ Language Summary

    IMAGE [Filename] : Reads the GDF map Filename. Default extension is .GDF
    KILL             : Kills pixels.
    SPECTRUM         : Extracts a spectrum from an image (to plot it).
1 IMAGE
        [GREG3\]IMAGE  [Filename]  [/PLANE  I1  I2]  [/SUBSET Imin Imax Jmin
    Jmax] [/WRITE] [/CLOSE]

    Associated "G_*" variables are defined after the first call to  the  IM‐
    AGE, SPECTRUM or KILL commands of GREG3\ language.

    Read  the  GDF  map  Filename. The default image extension is .GDF. This
    command defines the image found in given file as the new current  image.
    Projection,  system  and extremas are also defined if needed. Unless op‐
    tions are present, the first plane of the image becomes the new  Regular
    Grid array in GreG.

    The  /PLANE  I1  I2 option allows to define part of a more than 2‐Dimen‐
    sional image as the regular grid array. A file name should not be speci‐
    fied if you want to select a new plane in the current image.

    The  /SUBSET  Imin Imax Jmin Jmax option allows to load only a subset of
    the input image or image plane. Again, a file name should  be  specified
    only to change the input image.

    The  /WRITE  option  allows  you  to map the image writeable (instead of
    Readonly by default), a prerequisite to use some  functions  (e.g.  KILL
    which  kills  pixels).  The  mapped image is then non‐shareable by other
    users...

    The /CLOSE option allows you to close the currently opened file, and  to
    free associated memory, if any.

    You can combine /PLANE and /SUBSET options.
1 KILL
        [GREG3\]KILL

    KILL calls the interactive cursor. Recognised keys are:
      ‐ V to give the value of the pixel,
      ‐ K to give the current blanking value to the pixel,
      ‐ I to interpolate the value from the neighbour pixels,
      ‐ E to exit from interactive cursor mode.
    Any other key is ignored.
1 SPECTRUM
        [GREG3\]SPECTRUM I [J [K]]

    Extract a spectrum from an image according to the following numbering:
        Spectrum (l) = Image (l,i,j,k)
    for  a  4‐dimensional image. The spectrum is loaded into the X,Y buffers
    of GreG. It can be processed later by the standard commands LIMITS, CON‐
    NECT, CURVE and so on.
1 ENDOFHELP












