# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'surface1.14.png'
set dummy u,v
set label 1 "This is equal to 1" at 0, 3.2, 1 left norotate back nopoint
set arrow 1 from 0, 3, 1 to 0, 0, 1  back nofilled linetype 1 linewidth 1.000
set samples 51, 51
set isosamples 21, 21
set title "Sinc function" 0.000000,0.000000  font ""
set xlabel "X axis" -3.000000,-2.000000  font ""
set xrange [ -1.00000 : 1.00000 ] noreverse nowriteback
set ylabel "Y axis" 3.000000,-2.000000  font ""
set yrange [ -1.00000 : 1.00000 ] noreverse nowriteback
set zlabel "Z axis" -5.000000,0.000000  font ""
set zrange [ -1.00000 : 1.00000 ] noreverse nowriteback
sinc(u,v) = sin(sqrt(u**2+v**2)) / sqrt(u**2+v**2)
splot [-5:5.01] [-5:5.01] sinc(u,v)