idlines, specfile, linelist, xlo, xhi, xr, atoms, [ thresh, [ rv, ]] [/FIT,] [/EW|/NF,] [/ALL,] [/STIS,] [/XTEND,] [/XPAND,] [/MULT,] [/PRINT,] [/DUPLEX]
;   IDL procedure to display 
;   a) a region of spectrum, together with a fit, if supplied,
;   b) positions and relative strengths (gf or W_lambda) of lines in 
;   common atomic spectra may be marked in the lower panel. 
;   c) lines of sleceted atoms are identified in the top panel
;   Command arguments:
;   specfile - character string - name of file containing spectrum (and fit)
;                                 assumed to be x,y file with 3-line header
;   linelist - character string - name of file containing eq.widths
;                                 assumed to be 'spectrum' output
;   xlo      - real variable    - lower limit of plot
;   xhi      - real variable    - upper limit of plot
;   xr       - real variable    - range of indivusal plot   
;   atoms    - integer vector   - atomic numbers of spectra to be identified
;  [ thresh   - real variable    - threshold eq width or line strength to identi
fy lines ]
;  [ rv       - real variable    - radial velocity of spectrum ]
;   Keywords: 
;   /FIT     - overplot the fit 
;   /EW      - read and select the lines using equivalent widths 
;   /NF      - read and select the lines using n*gf (central opacities) 
;   /ALL     - plot individual atomic spectra schematically 
;   /MULT    - add multiplet labels to line ids 
;   /STIS    - to allow for air/vacuum shift at 2000A 
;   /DUPLEX  - plot 2 ranges of spectrum on one panel 
;   /XPAND   - expand plot by factor 5 
;   /XTEND   - extend line identification marks 
;   /PRINT   - plot hardcopy as a postscript file

readspec, file, specnw, specwav, specflx
;  read spectrum only (free format)
readspecfit, file, specnw, specwav, specflx, specfit
;  read spectrum and fit (sfit_synth output)
readlines, file, listn, listwav, listlab, listion, listmlt, listgf, listep, listfr
;  read lines from a linelist and returns them as an array of wavelengths,
;  labels, and ion identifications

markspec, zel, xlo, xhi, listn, listwav, listion, listlab, listmlt, listgf, listfr
; Assesses lines in linelist by the strength values "listfr".
; Positions of all lines are plotted for each element, relative to the strongest line
; due to each element in each spectral region. Note that these strengths are independent
; of abundance. The scale is logarithmic, such that the a line with 1/1000 strength
; of the the strongest line will not appear, ie if full scale = 0, the axis is at -3.
; Elements for which there are no lines in the spectral range are omitted.
markion, zel, xlo, xhi, listn, listwav, listion, listlab, listmlt, listfr, thresh