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        ANALYSE\LMV frequency/velocity axis

    If your input file is a Gildas cube (3 dimensions) but it has no or  in-
    complete  frequency/velocity  axis description (as found in the spectro-
    scopic section), it can not be imported as spectra into Class.

    However, you can fix this by setting by yourself this description in the
    file header. This can be achieved with Sic commands as follows:
      DEFINE HEADER H mycube.lmv WRITE
      LET H%F_AXIS   ??   ! [    ] Freq/Velo axis (1, 2 or 3)
      LET H%UNIT?    ??   ! [Keyword] Fill e.g. UNIT3 if F_AXIS is 3. Keyword mu
                                      be VELOCITY or FREQUENCY according to H%CO
      LET H%FREQRES  ??   ! [MHz ] Channel spacing
      LET H%IMAGFRE  ??   ! [MHz ] Image Frequency
      LET H%RESTFRE  ??   ! [MHz ] Rest frequency
      LET H%VELRES   ??   ! [km/s] Most likely -C*H%FREQRES/I%RESTFRE
      LET H%VELOFF   ??   ! [km/s] Velocity at reference channel H%CONVERT[2,H%F
      LET H%DOPPLER  ??   ! [    ] Doppler factor (Class convention)
      LET H%VTYPE    ??   ! [code] Velocity type (see codes in SIC%CODE%VELO%)
      LET H%SPEC     14   ! Section size => non-zero enables the section
      DELETE /VARIABLE H  ! Save the modifications in the file

    If your input cube is a FITS cube, you can either:
      - edit  the  FITS  with  you favorite FITS editor, and add the missing
        keywords, or
      - convert the FITS to the Gildas Data Format:
          V\FITS mycube.fits TO mycube.lmv
        and follow the steps above.

Gildas manager 2020-03-29