# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'pm3d.41.png'
unset border
unset key
set view map
set samples 4, 4
set isosamples 4, 4
set size ratio 0 0.333333,0.333333
set origin 0.333333,0.333333
set noxtics
set noytics
set ztics border in scale 2,1 nomirror norotate  offset character 0, 0, 0 autofreq 
set cbtics border in scale 2,1 mirror norotate  offset character 0, 0, 0 autofreq 
set title "Original grid points" 
set xrange [ 0.00000 : 3.00000 ] noreverse nowriteback
set yrange [ 0.00000 : 3.00000 ] noreverse nowriteback
set cbrange [ 0.00000 : 9.00000 ] noreverse nowriteback
set pm3d explicit at b
set pm3d interpolate 1,1 flush begin noftriangles nohidden3d corners2color median
unset colorbox
sinc(u,v) = sin(sqrt(u**2+v**2)) /sqrt(u**2+v**2)
f(x,y)=2*x+y
dx = 0.333333333333333
dy = 0.333333333333333
splot f(x,y) with linesp ps 3 pt 5 palette