[ncl-talk] Is my gsn_add_polyline usage wrong?

[Tomoko Koyama]

Hello.

I like to show a domain area a masked Lambert Conformal map.
But the following simple script doesn’t work.

Could you tell me what I miss?

Thank you,
Tomoko

;================================================;
begin
  wks = gsn_open_wks("X11","map_NSI")
;
; Set up some map resources.
;
  res                       = True
  res at gsnFrame              = False
  res at gsnDraw                = False
  res at gsnMaximize          = True

  res at mpProjection          = "LambertConformal"
  res at gsnMaskLambertConformal = True

  res at mpLimitMode           = "LatLon"
  res at mpMinLonF             =  90
  res at mpMaxLonF            =  180
  res at mpMinLatF              =  68
  res at mpMaxLatF             =  82

  res at tiMainString = "NSI Domain Area"
  map = gsn_csm_map(wks,res)

;************************************************
; create points for box
;************************************************
 ypts = (/ 80.0,  80.0, 70.0,  70.0, 80.0/)
 xpts = (/126.0, 158.0,158.0, 126.0,126.0/)
;************************************************
; add the box
;************************************************
  resp                  = True                      ; polyline mods desired

  dum = new(4,graphic)

  do i = 0 , 3
    dum(i) = gsn_add_polyline(wks,map,xpts(i:i+1),ypts(i:i+1),resp)
  end do

  draw(map)
  draw(wks)
end