rectangular grid lines on root locus plot

How can I put rectangular grid lines on a root locus plot?

[ashwani gupta]

It is not possible to do that probably Bcz if you are aware that the lines are for constant zeta and frequency.

Answer 1

[C.J. Harris]

Like this for example:

num = [1];
den = conv ([1 0] , [1 4 8]);
rlocus (num, den)
set(gca,'XGrid','on')
set(gca,'YGrid','on')