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linguist/samples/NCL/viewport_4.ncl
2015-07-09 07:17:01 -07:00

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; ***********************************************
; viewport_4.ncl
;
; Concepts illustrated:
; - Drawing an XY plot with multiple curves
; - Using drawNDCGrid to draw a nicely labeled NDC grid
; - Changing the size/shape of an XY plot using viewport resources
; - Drawing two XY plots on the same page using viewport resources
; - Drawing polylines, polymarkers, and text in NDC space
; - Using "getvalues" to retrieve resource values
; - Maximizing plots after they've been created
; ***********************************************
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"
;********************************************************************
; Draw a box around the viewport of the given object..
;********************************************************************
procedure draw_vp_box(wks,plot)
local vpx, vpy, vpw, vph, xbox, ybox, lnres, mkres, txres
begin
; Retrieve the viewport values of the drawable object.
getvalues plot
"vpXF" : vpx
"vpYF" : vpy
"vpWidthF" : vpw
"vpHeightF" : vph
end getvalues
; Set up some marker resources.
mkres = True
mkres@gsMarkerIndex = 16 ; filled dot
mkres@gsMarkerSizeF = 0.02 ; larger than default
mkres@gsMarkerColor = "Red"
; Draw a single marker at the vpXF/vpYF location.
gsn_polymarker_ndc(wks,vpx,vpy,mkres)
; Set up some text resources.
txres = True
txres@txJust = "BottomLeft"
txres@txFontHeightF = 0.018
txres@txFontColor = "Blue"
txres@txBackgroundFillColor = "white"
gsn_text_ndc(wks,"(vpXF="+vpx+", vpYF="+vpy+")",vpx,vpy+0.02,txres)
; Set up some line resources.
lnres = True
lnres@gsLineColor = "Red" ; line color
lnres@gsLineThicknessF = 2.0 ; 3.5 times as thick
; Draw lines indicating the width and height
xline = (/vpx, vpx+vpw/)
yline = (/vpy-0.05,vpy-0.05/)
gsn_polyline_ndc(wks,xline,yline,lnres)
xline = (/vpx+0.05,vpx+0.05/)
yline = (/vpy,vpy-vph/)
gsn_polyline_ndc(wks,xline,yline,lnres)
txres@txJust = "CenterCenter"
gsn_text_ndc(wks,"vpWidthF = " + vpw,vpx+vpw/2.,vpy-0.05,txres)
txres@txAngleF = 90.
gsn_text_ndc(wks,"vpHeightF = " + vph,vpx+0.05,vpy-vph/2.,txres)
end
;********************************************************************
; Main code
;********************************************************************
begin
;************************************************
; read in data
;************************************************
f = addfile ("$NCARG_ROOT/lib/ncarg/data/cdf/uv300.nc","r")
u = f->U ; get u data
;************************************************
; plotting parameters
;************************************************
wks = gsn_open_wks ("ps","viewport") ; open workstation
res = True ; plot mods desired
res@gsnFrame = False ; don't advance frame yet
res@vpWidthF = 0.8 ; set width and height
res@vpHeightF = 0.3
; First plot
res@tiMainString = "Plot 1"
res@vpXF = 0.15
res@vpYF = 0.9 ; Higher on the page
plot1 = gsn_csm_xy (wks,u&lat,u(0,:,{82}),res) ; create plot
; Second plot
res@tiMainString = "Plot 2"
res@vpXF = 0.15 ; Same X location as first plot
res@vpYF = 0.4 ; Lower on the page
plot2 = gsn_csm_xy (wks,u&lat,u(0,:,{3}),res) ; create plot
; Advance the frame
frame(wks)
; Now draw the two plots with illustrations.
drawNDCGrid(wks) ; Draw helpful grid lines showing NDC square.
draw(plot1) ; Draw the two plots
draw(plot2)
draw_vp_box(wks,plot1) ; Draw boxes around the two viewports.
draw_vp_box(wks,plot2)
frame(wks) ; Advance the frame.
;
; Uncomment the next two lines if you want to maximize these plots for
; PS or PDF output.
;
; psres = True
; maximize_output(wks,psres) ; calls draw and frame for you
end