#!/usr/local/bin/gnuplot -persist
# set terminal canvas  rounded size 600,400 enhanced fsize 10 lw 1.6 fontscale 1 name "pm3d_4" jsdir "."
# set output 'pm3d.4.js'
set border 4095 front lt black linewidth 1.000 dashtype solid
set samples 25, 25
set isosamples 20, 20
unset surface
set style data lines
set xyplane relative 0
set title "unset surface; set pm3d at st (surface and top)" 
set xlabel "x" 
set xrange [ -15.0000 : 15.0000 ] noreverse nowriteback
set x2range [ * : * ] noreverse writeback
set ylabel "y" 
set yrange [ -15.0000 : 15.0000 ] noreverse nowriteback
set y2range [ * : * ] noreverse writeback
set zrange [ -0.250000 : 1.00000 ] noreverse nowriteback
set cblabel "colour gradient" 
set cbrange [ * : * ] noreverse writeback
set rrange [ * : * ] noreverse writeback
set pm3d implicit at st
set colorbox vertical origin screen 0.9, 0.2 size screen 0.05, 0.6 front  noinvert bdefault
splot sin(sqrt(x**2+y**2))/sqrt(x**2+y**2)