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LMV FAXIS
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%LINE "SOMELINENAME"
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
2024-04-19