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        LAS\FIND /MASK [FileName]

    Select observations according the given mask.

    The file name should refer to a GDF file providing a 2D  (position-posi-
    tion) mask with <=0 or blank values (not selected), or >0 (selected) re-
    al values. The spectra from the input index are  selected  according  to
    their  position  (lamof, betof) on the mask. Positions completely out of
    the mask are not selected. Note that this command  does  not  check  the
    consistency  of  the  projection center, projection kind, and projection
    angle (only offsets are used).

    This option is best suited for use with the weight file (.wei)  produced
    by  the  command  XY_MAP, in which zero weights are put where no data is
    available. Using this weight file with FIND /MASK will thus ignore  pix-
    els/spectra with no data at all (all blank values).

    Another possibility is to produce a custom mask from an image, e.g.
      G\IMAGE myimage.gdf  ! or mycube.lmv
      G\LIMITS /RG
      G\POLYGON                           ! Define with cursor
      G\MASK OUT                          ! Mask pixels OUT of the polygon
      LET RG +1 /WHERE RG.NE.BLANKING[1]  ! Select pixels IN the polygon
      G\WRITE IMAGE mymask.gdf            ! Save into file
    In  this  example the cursor is used to define the mask, but one can use
    his own recipe to define the in/out rules.

    The default for FileName is the FILE IN VLM cube name if any,  with  the
    extension replaced by ".wei". Else, there is no default.

Gildas manager 2018-05-18