set terminal png
set output "interpolation.png"
set size 0.8,0.8

set xlabel "x"
set ylabel "y"
set title "Interpolation"
plot "points.dat" title "Datapoints" , \
     "pointerp.dat" with lines title "Polonomial Interpolation", \
     "qspline.dat" with lines title "Quadratic Spline"