;*************************************************
; color_14.ncl
;
; Concepts illustrated:
;   - Drawing grayscale filled contours
;   - Selecting a grayscale color map
;   - Setting a black background/white foreground
;
;************************************************
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
;************************************************
  a = addfile("$NCARG_ROOT/lib/ncarg/data/cdf/uv300.nc","r")
  u = a->U(1,:,:)                                ; read July zonal winds
;************************************************
; create plot
;************************************************
  wks = gsn_open_wks("ps","color")              ; open a ps file
  gsn_define_colormap(wks,"gsltod")             ; choose colormap


  res                      = True               ; plot mods desired
  res@cnFillOn             = True               ; turn on color fill

;---This resource not needed in NCL V6.1.0
  res@gsnSpreadColors      = True               ; use full range of colormap

  plot = gsn_csm_contour_map_ce(wks,u, res)     ; create plot

; reverse the first two colors
  setvalues wks            
    "wkColorMap"        : "gsltod"  
    "wkForegroundColor" : (/0.,0.,0./)  
    "wkBackgroundColor" : (/1.,1.,1./) 
  end setvalues
  plot = gsn_csm_contour_map_ce(wks,u, res)     ; create plot
  end