# set terminal pngcairo  transparent enhanced font "arial,10" fontscale 1.0 size 600, 400 
# set output 'pm3d.8.png'
set bar 1.000000 front
set border 4095 front lt black linewidth 1.000 dashtype solid
set style circle radius graph 0.02, first 0.00000, 0.00000 
set style ellipse size graph 0.05, 0.03, first 0.00000 angle 0 units xy
set style textbox transparent margins  1.0,  1.0 border
unset logscale
set view map scale 1
set samples 50, 50
set isosamples 50, 50
unset surface 
set style data pm3d
set style function pm3d
set xyplane relative 0
unset paxis 1 tics
unset paxis 2 tics
unset paxis 3 tics
unset paxis 4 tics
unset paxis 5 tics
unset paxis 6 tics
unset paxis 7 tics
set title "colour map, using default rgbformulae 7,5,15 ... traditional pm3d (black-blue-red-yellow)" 
set xlabel "x" 
set xrange [ -15.0000 : 15.0000 ] noreverse nowriteback
set ylabel "y" 
set yrange [ -15.0000 : 15.0000 ] noreverse nowriteback
set zrange [ -0.250000 : 1.00000 ] noreverse nowriteback
set paxis 1 range [ * : * ] noreverse nowriteback
set paxis 2 range [ * : * ] noreverse nowriteback
set paxis 3 range [ * : * ] noreverse nowriteback
set paxis 4 range [ * : * ] noreverse nowriteback
set paxis 5 range [ * : * ] noreverse nowriteback
set paxis 6 range [ * : * ] noreverse nowriteback
set paxis 7 range [ * : * ] noreverse nowriteback
set pm3d implicit at b
set colorbox vertical origin screen 0.9, 0.2, 0 size screen 0.05, 0.6, 0 front  noinvert bdefault
splot sin(sqrt(x**2+y**2))/sqrt(x**2+y**2)