xample above, <code>dem2</code> has much more and higher
drops compared to <code>dem1</code>. We can see its effect on the height
variation method by looking at the diagnostics plot. The dots in the
diagnostic plot for <code>dem2</code> follow a curve, and do not fall on
a straight line. The variance of D in <code>dem2</code> (var = 0.44) is
also larger than for <code>dem1</code> (0.24). Moreover, the frequency
of drops correlates slightly negatively with the fractal dimension
estimates when using the <code