Why the origin of Z-axis is not on the XY-plane? - Gnuplot Programming

Why the origin of Z-axis is not on the XY-plane?

- The zero-point of Z-axis is placed above the XY plane of splot.

- ‘set ticslevel’ is used to move this origin onto the XY plane.

- By setting ticslevel=0, the zero of Z-axis moves onto the XY plane.

- The following is the script to do this:

gnuplot> set ticslevel 0
gnuplot> splot (x**2)*(y**2)