[ncl-talk] Question about adding stipples on contour map

[Wang, Jiali]

Dear NCL experts,

I am trying to add stipples (or hatchings, doesn't matter) on a contour map when my "alpha >2". I plot alpha, which is not always larger than 2, meaning that I should have some places where I don't have stipples. However, I get stipples everywhere even when I set the threshold to 4. Attached are two maps, one is alpha, and the other is something else but with sitpples when alpha>2.

Here is my script. Can you please take a look and advice what happens? Thank you very much!
=============================================
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"

begin

   files1  = systemfunc("ls ./T2_IV_DJF_50_rs*.nc")
   a       = addfiles(files1,"r")

   f = addfile("T2_IV_DJF_12to50_16m.nc","r")
   c = addfile("/global/cscratch1/sd/wangjl/RCP85_IV_RUNS/50km_1995_IV_runs/wrfout_d01_1996-03-01_00_00_00"+".nc","r")

  lat = c->XLAT(0,:,:)
  lon = c->XLONG(0,:,:)

  ListSetType (a, "join")
  IV_10 = a[:]->IV
  IV_16 = f->IV

  rain  = new(dimsizes(IV_10),typeof(IV_10))
do r = 0, 199
  rain(r,:,:)  = IV_10(r,:,:) - IV_16(:,:)
end do
  printVarSummary (rain)

  std_r  = dim_stddev_n(rain,0)
  avg_r  = dim_avg_n(rain,0)
  alpha  = abs(avg_r/(std_r+0.00001))
; printMinMax(alpha,0)

ff   = addfile("$NCARG_ROOT/lib/ncarg/data/cdf/landsea.nc","r")
lsdata = ff->LSMASK
lsm    = landsea_mask(lsdata,lat,lon)
avg_r  = mask(avg_r, lsm .eq.0 .or. lsm.eq.2, False)
alpha  = mask(alpha, lsm .eq.0 .or. lsm.eq.2, False)

;;;;;;;;;;;;;;;;;;;;;;contour plot
  type = "ps"
  wks = gsn_open_wks(type,"T2_IV_DJF_50_vs_12_1995")  ;;;no 1983 for sum, aut, win
  gsn_define_colormap(wks,"ViBlGrWhYeOrRe")

  res = True
  pltres = True
  mpres = True

  mpres at mpGeophysicalLineColor = "Black"
  mpres at mpNationalLineColor    = "Black"
  mpres at mpUSStateLineColor     = "Black"
  mpres at mpGridAndLimbOn        = False
  mpres at tiMainString           = "IV 50 vs. 12"
  mpres at tiMainFontHeightF      = 0.015

;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;

  ; Plotting options for Precipitation
  opts_r = res
  opts_r at cnFillMode = "RasterFill"
opts_r at cnLevelSelectionMode = "ManualLevels"      ; set manual contour levels
opts_r at cnMinLevelValF       = -3.      ; set min contour level
opts_r at cnMaxLevelValF       = 3.         ; set max contour level
opts_r at cnLevelSpacingF      = .3           ; set contour spacing
  opts_r at cnInfoLabelOn        = False
  opts_r at cnConstFLabelOn      = False
  opts_r at cnFillOn             = True
  opts_r at lbLabelFont = 25
  opts_r at pmLabelBarOrthogonalPosF= -0.012
  contour_tot = wrf_contour(c,wks,avg_r,opts_r)
  delete(opts_r)
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
; Plotting options for Significant level
  opts = res
  opts at cnFillOn        = False
  opts at cnLinesOn       = False
  opts at cnLineLabelsOn  = False
  contour_sgl = wrf_contour(c,wks,alpha,opts)
  contour_sgl = ShadeGtContour(contour_sgl,4.,17)
  delete(opts)

  ; MAKE PLOTS
  plot = wrf_map_overlays(c,wks,(/contour_tot,contour_sgl/),pltres,mpres)

end
=======================
Jiali Wang, Ph. D
Environmental Science Division
Argonne National Laboratory
Tel: 630-252-2848
http://www.evs.anl.gov/about-evs/staff/detail/index.cfm?/Wang/Jiali

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20170718/70a00f5f/attachment-0001.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: alpha.ps
Type: application/postscript
Size: 759830 bytes
Desc: alpha.ps
Url : http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20170718/70a00f5f/attachment-0002.ps 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: plotting.ps
Type: application/postscript
Size: 1110583 bytes
Desc: plotting.ps
Url : http://mailman.ucar.edu/pipermail/ncl-talk/attachments/20170718/70a00f5f/attachment-0003.ps