It is possible to plot a surface and its projection as a color image on the x-y plane on the same graph. The two simultaneous views of the same data or function can be useful to bring out the topography of a complex surface.
The previous figure shows a simple trigonometric function of two variables displayed as a surface with its values simultaneously encoded into colors (or gray values) at the base of the plot.
The following script produces the previous figure as its output:
set iso 40 set samp 40 unset key set xrange [-pi:pi] set yrange [-pi:pi] f(x,y) = sin(x)*cos(y) set hidden front set xyplane at -1 ...