MAP_COMBINE

        [CLEAN\]MAP_COMBINE OutCube CODE In1 In2 [Off] [/FACTOR A1 A2]
      [/THRESHOLD T1 T2] [/BLANKING Bval]

    Combine  in  different  ways  two input images (or data cubes).  MAP_COMBINE
    does **NOT** request that the inputs have the same angular resolution,  nei-
    ther  the  same  unit.  It is up to the user to avoid combining inconsistent
    quantities !...

    However, MAP_COMBINE attempts to handle input data in different units  in  a
    reasonably  clever  way,  converting  different brightness quantities into a
    single  unit.  Accordingly,  depending  on  the  requested  operation  CODE,
    MAP_COMBINE  will  return the results in different units.  In practice, this
    is K for brightness (ADD), and no unit for Ratio (DIVIDE), Opacities  (OPAC-
    ITY) or Spectral Index (INDEX).

      MAP_COMBINE also supports an "intuitive" , more mathematical syntax,
          MAP_COMBINE OutCube = [A1*]In1 Oper [A2*]In2 [Off]
      [/THRESHOLD T1 T2] [/BLANKING Bval]

    where  Oper can be any of the values allowed for CODE, or one of the 4 stan-
    dard operators, +-/*, and scale factors are given in a natural way.

    CODE is the Operation Code: see HELP MAP_COMBINE CODE for details.   Off  is
    an optional offset for the operation.

    OutCube  can be a file name or an existing SIC Image variable.  The distinc-
    tion is made by the existence of a "." in the name.  If it is a file, it  is
    created  like  the In1 Variable If it is a SIC Image variable, it must exist
    and match the shape of In1.

    In1 can be a file name or an existing SIC Image variable.

    In2 can be a file name or an existing Image variable.  The rank of In2  must
    be smaller than or equal to that of In1, and other dimensions must match.

    A1 and A2 are scale factors applied to In1 and In2 if needed (default 1).

    T1 and T2 are thresholds below which no result is computed (default none).