;*************************************************
; polyg_6.ncl
;************************************************
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"  
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"  
;************************************************
begin
;************************************************
; read in netCDF file
;************************************************
  in   = addfile("uv300.nc","r")
  lat  = in ->lat
  lon  = in ->lon
  nlat = dimsizes(lat)
  nlon = dimsizes(lon)
;************************************************
; create default plot
;************************************************
  wks = gsn_open_wks("ps","polyg")                ; open a ps file

  res               = True                        ; plot mods desired
  res@gsnDraw       = False                       ; don't draw yet
  res@gsnFrame      = False                       ; don't advance frame
  res@tiMainString  = "Grid of two dimensional data"
  plot = gsn_csm_map_ce(wks,res)                 ; draw global map
;************************************************
; draw longitude lines
;************************************************
  dum = new(dimsizes(lon),graphic)
  do i = 0 ,nlon-1,3
    dum(i) = gsn_add_polyline(wks,plot,(/lon(i),lon(i)/),(/lat(0),lat(nlat-1)/),False)
  end do
;************************************************
; draw longitude lines
;************************************************
  dum1 = new(dimsizes(lat),graphic)
  do i = 0 ,nlat-1,3
    dum1(i) = gsn_add_polyline(wks,plot,(/lon(0),lon(nlon-1)/),(/lat(i),lat(i)/),False)
  end do
  draw(plot)
  frame(wks)
end