Error with drawing a polygon in a polar sterographic map

Hi,

I am trying put a box around the region of interest. But I get two errors
and I am not sure how to get a handle around it.

One is
Warning: You should not set the mpMinLonf and /or MarLonF resources.

fatal: NhlCvStringToEnum:Unable to convert string "missing" to requested
type

Warning : Error retrieving resource om Just from args-Ignoring Args.

Here is the code:-

I want to put a box around a particular region and the extract the data and
take average of that region. Do it for all the time series

;Date:07/23/2014
;Ipshita Majhi

;************************************************
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("~/Documents/Snow_cover_IMS/nhsce_v01r01_19661004_20140602.nc
","r")

sce=a->snow_cover_extent(0,:,:)
lat=a->latitude
lon=a->longitude


;Attaching latitude and longitude to sce
sce@lat2d=lat
sce@lon2d=lon


;************************************************
; create plot
;************************************************
  wks = gsn_open_wks("ps","polyg") ; open a ncgm file

  res = True ; plot mods desired
  res@gsnDraw = False ; don't draw yet
  res@gsnFrame = False ; don't advance yet

  res@mpMinLatF = 40 ; zoom in on a subregion
  res@mpMaxLatF = 60
  res@mpMinLonF = 10
  res@mpMaxLonF = 30

res@gsnPolar = "NH" ; specify the hemisphere
plot = gsn_csm_contour_map_polar(wks,sce,res) ; create the plot

;************************************************
; create points for box
;************************************************
 ypts = (/ 30.0, 30.0, 0.0, 0.0, 30.0/)
 xpts = (/-90.0, -45.0,-45.0, -90.0,-90.0/)
;************************************************
; add the box

Received on Wed Jul 23 07:44:43 2014