drawing polymarkers/gons shaded by corresponding scalar field

From: Marc Pace Marcella <marcpace_at_nyahnyahspammersnyahnyah>
Date: Tue Jun 04 2013 - 21:23:54 MDT

Hi all,

I am trying to take lat/lon data I have for rainfall and plot these on a map as scatter points via polymarkers (or polygons) that are shaded (or filled) with the corresponding rainfall values to a predefined NCL color map (in this case converting WhiteYellowOrangeRed rgb to cmap).

I have looked at the polygon climate division example script and figured that the function GetFillColor would be my best option and to follow this script. However, I do not have input polygons for the locations as the example has (only lat lon values) and I am having problems drawing "dummy" square polygons to then fill in. Below is what I have but that currently does not work properly. Any help would be greatly appreciated. Thanks!

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
;the data in pre(lat,lon,value) 3D

;or separated 1D arrays

cont_lat = cont_data(:,0)
cont_lon = cont_data(:,1)
cont_loss= cont_data(:,2)

;-------------------------- plot stuff ---------------------------

  wks = gsn_open_wks ("pdf","loss_polyg")

; resources for the plot

; map resources for projection

  res@mpLimitMode<mailto:res@mpLimitMode> = "LatLon"
  res@mpMinLatF<mailto:res@mpMinLatF> = 04.0 ; map area
  res@mpMaxLatF<mailto:res@mpMaxLatF> = 24.0 ; latitudes
  res@mpMinLonF<mailto:res@mpMinLonF> = 115.0 ; and
  res@mpMaxLonF<mailto:res@mpMaxLonF> = 135.0 ; longitudes

; map resources
  ;res@mpDataBaseVersion = "Ncarg4_1"
  res@mpFillOn<mailto:res@mpFillOn> = True
  res@mpGridAndLimbOn<mailto:res@mpGridAndLimbOn> = False

; polygon resources
  res_poly = True
  res_poly@gsEdgesOn<mailto:res_poly@gsEdgesOn> = True ; draw border around polygons
  res_poly@gsEdgeColor<mailto:res_poly@gsEdgeColor> = "black"

  res@mpFillOn<mailto:res@mpFillOn> = False
  res@mpPerimOn<mailto:res@mpPerimOn> = False
  res@mpGridAndLimbOn<mailto:res@mpGridAndLimbOn> = False

  res@gsnDraw<mailto:res@gsnDraw> = False ; don't draw the plots now
  res@gsnFrame<mailto:res@gsnFrame> = False ; or advance the frame

;converting rgb to colormap
  cmap = RGBtoCmap ("WhiteYellowOrangeRed.rgb")
  gsn_define_colormap (wks,cmap)

plot = gsn_map(wks,"Mercator",res)
; plot color coded climate division annual mean total precipitation
; for each of the polygons
; contour levels
  cnLevels = ispan(1,100,2)

; get correct color to fill polygon

 do i=0,cont_size-1,1
      res_poly@gsFillColor<mailto:res_poly@gsFillColor> = GetFillColor(cnLevels,cmap,cont_loss(i))
      gsn_polygon (wks,plot,cont_poly_x,cont_poly_y,res_poly)
  end do


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Received on Tue Jun 4 21:24:08 2013

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