# set terminal png transparent nocrop enhanced font arial 8 size 420,320 
# set output 'contours.21.png'
set view 0, 0, 1, 1
set samples 25, 25
set isosamples 26, 26
unset surface
set contour base
set cntrparam bspline
set cntrparam levels auto 10
set style data lines
set title "3D gnuplot demo - 2D contour projection of last plot" 0.000000,0.000000  font ""
set xlabel "X axis" -5.000000,-2.000000  font ""
set xrange [ * : * ] noreverse nowriteback  # (currently [0.00000:15.0000] )
set ylabel "Y axis" 4.000000,-1.000000  font ""
set yrange [ * : * ] noreverse nowriteback  # (currently [0.00000:15.0000] )
set zlabel "Z axis" 0.000000,0.000000  font ""
set zrange [ -1.20000 : 1.20000 ] noreverse nowriteback
splot "glass.dat" using 1