NCL/ImageMagick example to tilt a contour plot#
Run the Korn-Shell script Tilting_Plot.ksh:
ksh Tilting_Plot.ksh
Example Korn-Shell script:
#!/bin/ksh
#-----------------------------------------------------------------------------------
# DKRZ NCL example: Tilting_Plot.ksh
#
# Description: KSH-script to create contour, title and labelbar plot
# generated by an NCL script, tilt the contour plot, and
# compose all with ImageMagick's 'convert' to one.
#
# Graphic Software: NCL 6.3.0
# Image manipulation: ImageMagick 6.9.1-7
#
# 22.07.16 meier-fleischer(at)dkrz.de
#-----------------------------------------------------------------------------------
RUN_NCL=1 #-- run/skip NCL (1: do it)
RUN_COMPOSE=1 #-- run/skip ImageMagick distort/composite (1: do it)
NCL_SCRIPT="contour_plot.ncl" #-- name of the NCL script
IFILE="tas_rectilinear_grid_2D.nc" #-- input file
#***********************************************
#-------------------------------
#-- write NCL script
#-------------------------------
cat << EOF > ${NCL_SCRIPT}
;--------------------------------------------------------
; DKRZ NCL example: ${NCL_SCRIPT}
;
; Description: Create a contour plot in one frame,
; title and labelbar in another frame each.
;
; This script is part of the Pseudo_3D_plots
; examples to generate 3D looking images.
;
; NCL Version: 6.3.0
;
; 22.07.16 meier-fleischer(at)dkrz.de
;--------------------------------------------------------
begin
title = "NCL contour plot tilted and composed by ImageMagick"
f = addfile("${IFILE}","r") ;-- open input file
var = f->tas(0,:,:) ;-- read variable first time step
;-- contour plot workstation
wks_type = "png"
wks_type@wkWidth = 2500
wks_type@wkHeight = 2500
wks = gsn_open_wks(wks_type, "plot_contour")
;-- title plot workstation
wkst_type = "png"
wkst_type@wkWidth = 2500
wkst_type@wkHeight = 2500
wkst = gsn_open_wks(wkst_type, "plot_title")
;-- labelbar plot workstation
wksl_type = "png"
wksl_type@wkWidth = 2500
wksl_type@wkHeight = 2500
wksl = gsn_open_wks(wksl_type, "plot_labelbar")
;-------------------------------
;-- Contour plot:
;-------------------------------
res = True
res@gsnLeftString = "" ;-- no left string
res@gsnRightString = "" ;-- no right string
res@cnFillOn = True
res@cnLinesOn = False ;-- turn off contour lines
res@cnLineLabelsOn = False ;-- turns off contour line labels
res@cnInfoLabelOn = False ;-- turns off contour info label
res@cnMissingValFillColor = "wheat4" ;-- missing value color
res@cnMissingValFillPattern = 0 ;-- 0: solid fill
res@mpGeophysicalLineThicknessF = 4.0 ;-- increase coastal outlines thicker
res@lbLabelBarOn = False ;-- don't draw labelbar
contour = gsn_csm_contour_map(wks,var,res) ;-- create plot; advance contour frame
print(" - contour plot done")
;-------------------------------
;-- Title plot:
;-------------------------------
tires = True
tires@txJust = "CenterCenter" ;-- text justification
tires@txFontHeightF = 0.017 ;-- text font size
tix = 0.5
tiy = 0.8
gsn_text_ndc(wkst,title,tix,tiy,tires) ;-- draw title
print(" - title plot done")
frame(wkst) ;-- advance title frame
;-------------------------------
;-- Labelbar plot:
;-------------------------------
;-- retrieve the contour resources for the labelbar
getvalues contour@contour
"cnLevels" : cnlevs ;-- contour levels
"cnFillColors" : cncols ;-- contour colors
"cnMonoFillPattern" : mpattern ;-- contour fill pattern
end getvalues
labels = ""+cnlevs ;-- labelbar labels
nboxes = dimsizes(cnlevs)+1 ;-- number of color boxes
lbx = 0.3 ;-- labelbar x-position
lby = 0.9 ;-- labelbar y-position
lbw = 0.2 ;-- labelbar width
lbh = 0.8 ;-- labelbar height
;-- labelbar resources
lbres = True
lbres@lbAutoManage = False ;-- we want to control the labelbar
lbres@lbOrientation = "vertical" ;-- labelbar orientation
lbres@lbLabelFontHeightF = 0.024 ;-- increase label font size
lbres@lbLabelFontThicknessF = 4. ;-- increase label font thickness
lbres@lbLabelStride = 1 ;-- label every value
lbres@lbPerimOn = False ;-- no box around labelbar
lbres@lbLabelFontColor = "black" ;-- labe font color
lbres@lbLabelAlignment = "InteriorEdges" ;-- where to draw the labels
lbres@lbLabelOffsetF = 0.05 ;-- move labels to the right
lbres@lbMonoFillPattern = mpattern ;-- use same fill pattern as contour plot
lbres@lbMonoFillColor = False ;-- use multiple colors
lbres@lbFillColors = cncols ;-- contour colors
lbres@lbLabelStrings = labels ;-- contour labels
lbres@vpWidthF = lbw ;-- labelbar viewport width
lbres@vpHeightF = lbh ;-- labelbar viewport height
gsn_labelbar_ndc(wksl,nboxes,labels,lbx,lby,lbres) ;-- draw labelbar
;-- text resources labelbar annotations
txres = True
txres@txFontHeightF = 0.018 ;-- units text font size
gsn_text_ndc(wksl, "[C~S~o~N~]", 0.440, 0.12, txres) ;-- add units to labelbar
print(" - labelbar plot done")
frame(wksl) ;-- advance labelbar frame
end
EOF
#***********************************************
#-------------------------------------------------------------------
#-- run NCL scripts to generate the input images
#-------------------------------------------------------------------
if [[ $RUN_NCL == 1 ]] ; then
rm -rf plot_*.png #-- delete all old plots
echo "--------------------------------------------"
echo "** run NCL script"
ncl -Q -n ${NCL_SCRIPT} #-- run NCL without standard output
fi
#***********************************************
#-------------------------------------------------------------------
#-- do the tilting of the plot and create the composed plot
#-------------------------------------------------------------------
if [[ $RUN_COMPOSE == 1 ]] ; then
echo "--------------------------------------------"
echo "** run ImageMagick"
rm -rf compose.jpg #-- delete old composed file
#-- new width and height of sheared image
co="plot_contour.png"
co_width=2800 ; co_height=900
dxco=50 ; dyco=500
angle=-40
#-- labelbar vertical
lb="plot_labelbar.png"
lb_width=115 ; lb_height=700
dxlb=2420 ; dylb=535
#-- title string
ti="plot_title.png"
ti_width=2000 ; ti_height=100
dxti=400 ; dyti=150
#-- cut off white space around te plot
convert -alpha off -background white -density 300 -trim $co tmp_c.png
convert -alpha off -background white -density 300 -trim $ti tmp_t.png
convert -alpha off -background white -density 300 -trim $lb tmp_l.png
echo " - crop white space done"
#-- original and new coordinate positions of the edges
xul=0 ; dxul=400
yul=0 ; dyul=50
xur=2200 ; dxur=1500
yur=0 ; dyur=50
xlr=2200 ; dxlr=1900
ylr=1200 ; dylr=1200
xll=0 ; dxll=0
yll=1200 ; dyll=1200
#-- do the distortion and write the result to a temporary file
convert tmp_c.png -matte -virtual-pixel transparent \
-distort Perspective "$xul,$yul $dxul,$dyul \
$xur,$yur $dxur,$dyur \
$xlr,$ylr $dxlr,$dylr \
$xll,$yll $dxll,$dyll" tmp_contour.png
echo " - distortion done"
#-- compose all images a one new image of size 16:9
convert -size 3000x1688 xc: \
\( tmp_contour.png -resize ${co_width}x${co_height}! \) -geometry +${dxco}+${dyco} -composite \
\( tmp_l.png -resize ${lb_width}x${lb_height}! \) -geometry +${dxlb}+${dylb} -composite \
\( tmp_t.png -resize ${ti_width}x${ti_height}! \) -geometry +${dxti}+${dyti} -composite \
tmp_compose.jpg
echo " - composition done"
#-- resize image to standard 1920x1080 pixel size
convert -resize 1920x1080 tmp_compose.jpg compose_1_tilted_plot.jpg
#-- clean up
rm -rf tmp_*.png tmp_*.jpg
fi
echo "--------------------------------------------"
#***********************************************
exit
Result:
