# 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 style increment default
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
splot sin(sqrt(x**2+y**2))/sqrt(x**2+y**2)