### Bridge toward GREG functionalities

The spectra and the results of their analysis (like the fits) are in CLASS internal buffers not always easily accessible for plotting with the GREG commands. CLASS thus implements the GREG command which is intended to produce a direct interface with GREG for plots of spectra. It creates a GILDAS table which can be read using the standard GREG commands for further plotting. The table contains the following columns for Spectra:

    1. Intensity
    2. Channel number
    3. Velocity
    4. Offset frequency
    5. Rest frequency
    6. Image frequency
    7. Fitted profiles if any - fit(i),i=0,nline - in column 7+i,
       for the current method.

The output table can be put later in a formatted way using GILDAS task LIST if needed. For continuum data, the table contains

    1. Intensity
    2. Channel number
    3. Angular offset (radian)
    4. Fitted profile if any.

The table may be used as input to GREG to produce fancy plots, or by the GILDAS software for other applications. In particular, the SIC monitor (command LET) is able to subtract any of the fits from the spectrum to produce residuals if needed. It is possible to merge different tables, add columns to a table, etc... For example, from two spectra at the same velocity resolution it is possible to merge the two tables and compute the ratio of the spectra, as well as the errors on this ratio.