Sorting

In the previous visualization, the dumped spectra were order according to their observation number, which most often corresponds to the observing time sequence. However, it often happens that two sequential OTF scans belongs to 2 far-away part of the same source. It is thus desirable to be able to sort dumped spectra in the index by coordinates. In CLASS90, the ``set sort keyword'' command defines the sorting that will be applied when the index will be built by the next find command. In particular, the keyword may be lambda or beta. Fig.  shows the results of the following commands

          LAS90> set mode y 0 8
          LAS90> set angle second
          LAS90> set sort beta
          LAS90> for ilambda -470 to -260 by 30
          LAS90>    find /range 'ilambda' 'ilambda+10' * *
          LAS90>    if (found.ne.0) then
          LAS90>       load
          LAS90>       plot /index
          LAS90>       g\draw text 0 1 'ilambda'"` < lambda < "'ilambda+10'"`" 5 /char 8
          LAS90>       list
          LAS90>       pause
          LAS90>    endif
          LAS90> next

which enables to view the dumped spectra with a good continuity in intensity.

Figure: Beta sorted series of dumped spectra intensities as a function of the velocity. For each panel, only the spectra with a lambda offset belonging to the same spatial resolution bin is shown. This is the way to ensure the best possible intensity continuity from one to another dumped spectra.