load "$NCARG_ROOT/lib/ncarg/nclex/gsun/gsn_code.ncl"

begin
;
; Open a netCDF file containing storm data.
;
  tfile = addfile("$NCARG_ROOT/lib/ncarg/data/cdf/Tstorm.cdf","r")
;
; Get the temperature arrays for the first 6 time steps.
;
  nplots = 6
  temp = tfile->t(0:nplots-1,:,:)

;
; Save the lat and lon arrays to a variable.
;
  lat = tfile->t&lat
  lon = tfile->t&lon

  lat@name = "latitude"    ; Name the lat variable.
  lon@name = "longitude"   ; Name the lon variable.

  wks = gsn_open_wks("x11","panel")  ; Open an X11 workstation.

;
; Define a color map.
;
  cmap = (/(/1.00,1.00,1.00/),(/0.00,0.00,0.00/),(/1.00,.000,.000/),\
           (/.950,.010,.000/),(/.870,.050,.000/),(/.800,.090,.000/),\
           (/.700,.090,.000/),(/.700,.120,.000/),(/.700,.180,.000/),\
           (/.700,.260,.000/),(/.700,.285,.000/),(/.680,.330,.000/),\
           (/.570,.420,.000/),(/.560,.530,.000/),(/.550,.550,.000/),\
           (/.130,.570,.000/),(/.060,.680,.000/),(/.000,.690,.000/),\
           (/.000,.700,.100/),(/.000,.600,.300/),(/.000,.500,.500/),\
           (/.000,.400,.700/),(/.000,.300,.700/),(/.000,.200,.700/),\
           (/.000,.100,.700/),(/.000,.000,.700/),(/.100,.100,.700/),\
           (/.200,.200,.700/),(/.300,.300,.700/),(/.420,.400,.700/),\
           (/.560,.500,.700/),(/.610,.600,.700/),(/.700,.700,.700/)/)

  gsn_define_colormap(wks,cmap)

;
; The next set of resources will apply to all four plots.
;
  resources               = True

  resources@gsnDraw       = False      ; Don't draw plot or advance the
  resources@gsnFrame      = False      ; frame after plot is created.
;
; Loop through four of the timesteps and create each plot. Title each
; plot according to which timestep it is.
;

  plot = new(nplots,graphic)
  do i=0,nplots-1
    resources@tiMainString  = "Temperature at time = " + i
    plot(i) = gsn_contour(wks,temp(i,:,:),resources)
  end do

  gsn_panel(wks,plot(0:3),(/2,2/),False) ; Draw 2 rows/2 columns of plots.

;
; This section will set resources for drawing contour plots
; over a map.
;
  delete(resources@tiMainString)  ; Don't set a main title.

  resources@sfXArray       = lon  ; Portion of map on which to overlay
  resources@sfYArray       = lat  ; contour plot.

  resources@cnInfoLabelOn  = False   ; Turn off info label.
  resources@cnLineLabelsOn = False   ; Turn off contour line labels.
  resources@cnLinesOn      = False   ; Turn off contour lines.
  resources@cnFillOn       = True    ; Turn on contour fill.

  resources@cnLevelSelectionMode = "ManualLevels"  ; Select contour levels.
  resources@cnMinLevelValF       = 245.
  resources@cnMaxLevelValF       = 302.5
  resources@cnLevelSpacingF      =   2.5

  resources@mpLimitMode    = "LatLon"  ; Limit portion of map that is viewed.
  resources@mpMinLatF      = min(lat)
  resources@mpMaxLatF      = max(lat)
  resources@mpMinLonF      = min(lon)
  resources@mpMaxLonF      = max(lon)

  resources@mpPerimOn       = True    ; Turn on map perimeter.
  resources@mpGridAndLimbOn = False   ; Turn off map grid.

  do i=0,nplots-1
    plot(i) = gsn_contour_map(wks,temp(i,:,:),resources)
  end do

  panelres                = True
  panelres@gsnFrame       = False ; Don't advance the frame.
  panelres@gsnPanelBottom = 0.1   ; More white space at bottom for labelbar.
                                  ; Default is 0.

  gsn_panel(wks,plot,(/3,2/),panelres)  ; Draw 3 rows and 2 columns of plots.

;
; Draw two titles at the top.
;
  textres               = True
  textres@txFontHeightF = 0.025   ; Size of title.

  gsn_text_ndc(wks,":F26:Temperature (K) at every six hours",0.5,.97,textres)

  textres@txFontHeightF = 0.02    ; Make second title slightly smaller.

  gsn_text_ndc(wks,":F26:January 1996",0.5,.935,textres)

;
; Retrieve level and colors for use in labelbar.
;
  getvalues plot@contour
    "cnLevels"     : levels
    "cnFillColors" : colors
  end getvalues

;
; Only label every other line in the labelbar.
;
  lev_labels = new(dimsizes(levels),string)
  do i = 0,dimsizes(levels)-1,2
    lev_labels(i) = levels(i)
    if(i.lt.dimsizes(levels)-1) 
      lev_labels(i+1) = ""
    end if
  end do

  lbres = True

  lbres@lbFillColors       = colors           ; Set the colors to use.
  lbres@lbLabelAlignment   = "InteriorEdges"  ; Only label interior lines.
  lbres@lbLabelFont        = "helvetica-bold" ; Change label font.
  lbres@lbLabelFontHeightF = 0.07             ; Change label font height.
  lbres@lbMonoFillPattern  = True             ; Fill each box solid.
  lbres@lbOrientation      = "horizontal"     ; Horizontal labelbar.
  lbres@lbPerimOn          = False            ; Turn off perimeter.
  lbres@vpHeightF          = 0.2              ; Height of labelbar.
  lbres@vpWidthF           = 0.9              ; Width of labelbar.

  gsn_labelbar_ndc(wks,dimsizes(colors),lev_labels,0.05,0.2,lbres)

  frame(wks)   ; Advance the frame.
end