;+
; Set the flags for the VEGAS spurs in the currently opened input data
; source (either a single sdfits file or a directory). 
;
; <p>VEGAS produces spurs (spikes) at channels corresponding to
; integer multiples of the ADC sampler frequency divided by 64.  The
; normal behavior of sdfits is to flag these channels when the data
; are filled (use <a href="listflags">listflags</a> to see the list of
; flags for the currently opened input data set). This routine can be
; used to recreate those flags if the original flag file has been lost
; or corrupted.
;
; <p>A spur is also produced at the center channel (NCHAN/2 when
; counting from 0).  That spur does not arise in the ADC in VEGAS and
; so does not move as the spectral window is tuned across the ADC
; bandpass. This routine does not flag that spur.  Normal
; sdfits use will replace that spur with the average of the two
; adjacent channels and so it generally is not necessary to flag that
; spur.  Since that spur does not move as the spectral window is tuned
; it can be flagged using the standard flag command if necessary.
;
; <p>The routine first unflags all flags with the idstring
; "VEGAS_SPUR"
;
; <p>This routine expects to encounter uncalibrated VEGAS data filled
; by sdfits.  It checks that there is both an SDFITVER keyword and an
; INSTRUME keyword on the primary header of all SDFITS files.  The
; value of the INSTRUME keyword must be "VEGAS".
;
; <p>This spur locations are determined using the VSPDELT, VSPRPIX,
; and VSPRVAL columns.  For data filled using older versions of
; sdfits, these values are not present in the SDFITS tables. Such
; older data should be refilled using the most recent version of
; sdfits to make use of this procedure.
; 
; @keyword flagcenteradc {in}{optional}{type=boolean} When set, the
; center ADC spur is also flagged.  Normally that spur is left
; unflagged because sdfits usually replaces the value at that location
; with an average of the two adjacent channels and so that spur does
; not need to be flagged since it's been interpolated.
;
; @version $Id$
;-
pro flagspurs, flagcenteradc=flagcenteradc
  compile_opt idl2

  if not !g.line then begin
     message,'This does not work in continuum mode, sorry.', level=-1,/info
     return
  endif

  if not !g.lineio->is_data_loaded() then begin
     message,'No line data is attached yet, use filein, dirin, online, or offline', level=-1, /info
     return
  endif

  !g.lineio->reflag_vegas_spurs, flagcenteradc=flagcenteradc
end