;Read all data into a one-dimensional variable.
begin
;---Make a list of all files we are interested in
  
  files = (/ "flight1.csv","flight2.csv","flight3.csv","flight4.csv" /)
  
;---Start the graphics
  
  plot = new(4,graphic)
  wks = gsn_open_wks("png","flights_2008")
  data = asciiread(files(0),-1,"string")
  
  delim = ","
  
  flt  = str_get_field(data,1, delim)                   ; flight
  lat  = stringtofloat(str_get_field(data,2, delim))    ; latitude values
  lon  = stringtofloat(str_get_field(data,3, delim))    ; longitude values
  alt  = stringtofloat(str_get_field(data,4, delim))    ; altitude
  year = stringtoint(str_get_field(data,5, delim))      ; year
  mth  = stringtoint(str_get_field(data,6, delim))      ; month
  day  = stringtoint(str_get_field(data,7, delim))      ; day
  hr   = stringtoint(str_get_field(data,8, delim))      ; hour
  minute  = stringtoint(str_get_field(data,9, delim))      ; minute
  
  wks = gsn_open_wks("png","trajectory")  ; save as png
  
  res                   = True              ; plot mods desired
  res@pmTickMarkDisplayMode = "Always"
  res@mpFillOn              =  False           ; turn off map fill
  res@mpOutlineDrawOrder    = "PostDraw"       ; draw continental outline last
  res@mpOutlineBoundarySets = "GeophysicalAndUSStates" ; state boundaries
  
;-- set plot resources

  res@gsnDraw       =  False
  res@gsnFrame      =  False
  res@gsnMaximize   =  True
  
  res@mpMinLatF     =   38.0
  res@mpMaxLatF     =   45.0
  res@mpMinLonF     =  -80.0
  res@mpMaxLonF     =  -72.0
  
;-- create basic map
  map = gsn_csm_map(wks,res) 
;--

  gres = True
  gres@gsLineThicknessF = 3.0                 ; line thickness
  gres@gsLineColor      = "Red"               ; line color 
;  plot1 = gsn_add_polyline(wks, map, lon, lat, gres)
  
  do i=1,3 
	data = asciiread(files(1),-1,"string")
	delim = ","
	lat  = stringtofloat(str_get_field(data,2, delim))    ; latitude values
	lon  = stringtofloat(str_get_field(data,3, delim))    ; longitude values
	plot(i) = gsn_add_polyline(wks, map, lon, lat, gres)
	overlay(map,plot(i))
;  delete( [/lon, lat/] ) ;deletes old array for next iteration
  end do

  draw(map)

  frame(wks)

end