#!/usr/local/bin/gnuplot -persist
# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'imageNaN.8.png'
unset key
set label 1 "NaN\nshould appear as\nbackground" at 3.00000, 2.00000, 0.00000 center norotate front nopoint
set label 2 "Negative values become NaN\nwith a log-scale color mapping" at 0.00000, 2.50000, 0.00000 left norotate back nopoint
unset parametric
unset xtics
unset ytics
set cbtics  norangelimit logscale autofreq 
set title "negative values mapped to log-scale colorbar" 
set xrange [ * : * ] noreverse writeback
set x2range [ * : * ] noreverse writeback
set yrange [ * : * ] noreverse writeback
set y2range [ * : * ] noreverse writeback
set zrange [ * : * ] noreverse writeback
set cbrange [ 0.100000 : 10.0000 ] noreverse writeback
set rrange [ * : * ] noreverse writeback
set logscale cb 10
set colorbox vertical origin screen 0.9, 0.2 size screen 0.05, 0.6 front  noinvert bdefault
NO_ANIMATION = 1
## Last datafile plotted: "$DATA"
plot $DATA with image, $DATA using 1:2:(sprintf("%g",$3)) with labels tc rgb "green"