Coloring the surface

The wireframe splot with hidden line removal that we covered in the first recipe of this chapter, Making a surface plot, gives the visual impression of a solid surface. The numerical value encoded into the surface's height can be visually estimated, roughly, by the perspective provided by the isolines in conjunction with the tics on the vertical axis. But gnuplot also has a way to draw real solid surfaces whose height is indicated by color or shade.

The previous figure shows the same mathematical function plotted in the first recipe in this chapter (Making a surface plot). Now the numerical value of the function at any point is indicated by both the height of the surface and its shade; the surface is now drawn as an opaque membrane rather than as a network of curves.

How to do it…

To produce the previous figure, run the following in gnuplot:

set isosamples 100
set samples 100
unset key
set title "J_0(r^2)"
set xrange [-4:4]
set yrange [-4:4]
set ztics 1
unset surface
set...