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

begin
  wks = gsn_open_wks("x11","poly2_ex")

  res           = True                        ; plot mods desired

  res@gsnMaximize = True                      ; maximize plot in frame

  res@mpMinLatF   = -20                       ; zoom in on a subregion
  res@mpMaxLatF   = 40
  res@mpMinLonF   = -130
  res@mpMaxLonF   = 0.

  map = gsn_csm_map(wks,res)
end