# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'pm3d.5.png'
set border 4095 lt -1 lw 1.000
set samples 25, 25
set isosamples 20, 20
unset surface
set ticslevel 0
set title "unset surface; set pm3d at st (surface and top)" 0.000000,0.000000  font ""
set xlabel "x" 0.000000,0.000000  font ""
set xrange [ -15.0000 : 15.0000 ] noreverse nowriteback
set ylabel "y" 0.000000,0.000000  font ""
set yrange [ -15.0000 : 15.0000 ] noreverse nowriteback
set zrange [ -0.250000 : 1.00000 ] noreverse nowriteback
set cblabel "colour gradient" 0.000000,0.000000  font ""
set pm3d at st
set pm3d scansautomatic flush begin noftriangles nohidden3d solid implicit corners2color mean
splot sin(sqrt(x**2+y**2))/sqrt(x**2+y**2)