load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"  
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"  

begin

  a = addfile("$NCARG_ROOT/lib/ncarg/data/cdf/Tstorm.cdf","r")

  t = a->t(0,:,:)

  wks  = gsn_open_wks("x11","conLab")
  
  res  = True

  res@tiMainString             = "Randomized: Default"
  plot = gsn_csm_contour(wks,t,res)
  setvalues plot
    "vpWidthF"  : .25
    "vpHeightF" : .25
  end setvalues
  draw(plot)
  frame(wks)

  res@cnLineLabelPlacementMode = "constant"
  res@tiMainString             = "Constant"
  plot = gsn_csm_contour(wks,t,res)
  setvalues plot
    "vpWidthF"  : .25
    "vpHeightF" : .25
  end setvalues
  draw(plot)
  frame(wks)

  delete(res@cnLineLabelPlacementMode)
  res@tiMainString             = "Computed"
  res@cnLineLabelPlacementMode = "computed"
  plot = gsn_csm_contour(wks,t,res)
  setvalues plot
    "vpWidthF"  : .25
    "vpHeightF" : .25
  end setvalues
  draw(plot)
  frame(wks)
end