function wrf_contour_ggp(nc_file:file,lat[*][*]:numeric, lon[*][*]:numeric, \
                     wks[1]: graphic, data[*][*]:numeric, \
                     opt_args[1]:logical)
 
; This function creates a contour plot and adds some titles to it.
;
;   1. Determine width to height ratio of plot.
;
;   2. First determine if this is to be a filled or line
;      contour plot (fill_on)
;
;   3. If the ContourParameters attribute is set, then calculate
;      the contour levels.
;
;   4. Set two resources for setting the zero contour line to 
;      a larger thickness, and for changing the negative contour
;      lines to a dashed pattern.
;
;   5. If doing a filled contour plot, set a title for the labelbar
;      based on whether a units attribute is set.
;
;   6. Make a copy of the resource list, and set some additional
;      resources for filled contour plots.
;
;   7. Create the contour plot, attach the titles, and draw
;      and advance the frame (if requested).
 
local dims
begin
  opts = opt_args      ; Make a copy of the resource list.

  if(opts.and.isatt(opts,"gsnDebugWriteFileName")) then
    wrf_debug_file = get_res_value(opts,"gsnDebugWriteFileName",  "")    
  end if
    
  if(opts.and.isatt(opts,"mpOutlineBoundarySets")) then
    delete(opts@mpOutlineBoundarySets)
  end if


; Calculate ratio of plot width and height. Note that this doesn't
; affect the setting of gsnMaximize to True, because gsnMaximize will
; retain the aspect ratio of the plot.

  if(opts.and.isatt(opts,"AspectRatio")) then
    ratio = opts@AspectRatio
  else
    dims  = dimsizes(data)
    ratio = 1.*dims(0)/dims(1)
    if(ratio .gt. 1.2) then
      ratio = 1.2
    end if
    if(ratio .lt. 0.6667) then
      ratio = 0.6667
    end if
  end if
  print(ratio)
  if(ratio .gt. 1) 
    width  = 0.95*1.0/ratio ;0.65 * 1.0/ratio
    height = 0.95 ;0.65
  else
    width  = 1.2
    height = 1.2 * ratio
  end if

  opts@vpWidthF = get_res_value_keep(opts,"vpWidthF",  width)
  opts@vpHeightF = get_res_value_keep(opts,"vpHeightF", height)


; Set some basic contour resources 
  opts = set_cn_resources(data,opts)


; Find out if we are working with a contour or a shaded plot
; fill_on = False : line contour plot
; fill_on = True  : filled contour plot
  fill_on = get_res_value_keep(opts,"cnFillOn",False)
  if(fill_on) then      ; set lb resources if needed
    opts = set_lb_resources(data,opts)
    atmp = get_res_value(opts,"lbLabelBarOn",True) ; Remove this resource
    delete(atmp)                                   ; just in case.
  end if


; Set Title resources
  opts = set_title_resources(data,opts)


; Setting gsnScale to True ensures that the tickmark lengths and labels
; will be the same size on both axes.
  opts@gsnScale    = get_res_value_keep(opts,"gsnScale",    True)


; The default is not to draw the plot or advance the frame, and
; to maximize the plot in the frame.
  opts@gsnDraw          = False    ; Make sure don't draw or frame or,
  opts@gsnFrame         = False    ; maximize, b/c we'll do this later.
  opts@gsnMaximize      = False


  opts2 = opts
  delete_attrs(opts2)                       ; Clean up.
  cn = gsn_contour(wks,data,opts2)          ; Create the plot.
  _SetMainTitle(nc_file,wks,cn,opts)        ; Set some titles

  if(isvar("wrf_debug_file")) then
    write_wrf_debug_info(wks,data,False,wrf_debug_file,opts2,"wrf_contour")
  end if

  opts2@gsnDraw     = get_res_value_keep(opts2,"gsnDraw",     False)
  opts2@gsnFrame    = get_res_value_keep(opts2,"gsnFrame",    False)
  opts2@gsnMaximize = get_res_value_keep(opts2,"gsnMaximize", True)
  draw_and_frame(wks,cn,opts2@gsnDraw,opts2@gsnFrame,False,opts2@gsnMaximize)

  return(cn)                                ; Return

end