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msgValOutline

Draws an outline around missing data in vector and streamline plots.

Prototype

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"

	function msgValOutline (
		wks      : graphic,  
		plot     : graphic,  
		x [*][*] : numeric   
	)

	return_val [1] :  graphic

Arguments

wks

A Workstation identifier. The identifier is one returned either from calling gsn_open_wks or calling create to create a Workstation object.

plot

The plot to be modified.

x

An array dimensioned lat x lon, which matches the array passed to the vector plotting function.

Return value

The modified plot is returned.

Description

This procedure returns plot with the missing data outlined in light gray. If there is no light gray in your colormap, then the next closest color will be used.

The missing values (x@_FillValue) of x are used to draw the outline.

You need to draw the plot and advance the frame after calling this function.

Examples

Example 1

load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl" 
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_csm.ncl" 
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/contributed.ncl"
load "$NCARG_ROOT/lib/ncarg/nclscripts/csm/shea_util.ncl"

begin
  f      = addfile ("/cgd/cas/shea/MURPHYS/ATMOS/80.nc", "r")
  uwnd      = f->u(0,17,:,:)
  vwnd      = f->v(0,17,:,:)
  uwnd@_FillValue = 1.e+20
  vwnd@_FillValue = 1.e+20
  uwnd({40.:60.},{140.:190.}) = uwnd@_FillValue     ;set an area to missing for demonstration purposes

  wks = gsn_open_wks("ps","test")
  res                     = True
  res@gsnDraw = False
  res@gsnFrame = False
  plot = gsn_csm_vector_map_ce(wks,uwnd(::2,::2),vwnd(::2,::2),res)   ;plot every other vector    
  plot = msgValOutline(wks,plot,w,uwnd(::2,::2))
  draw(plot)
  frame(wks)
end
For an application example, see: