MATLAB - Plot half the Nyquist Plot

Question

Is there a way to only plot half the nyquist plot in MATLAB? Nyquist usually has the two lines that go in opposite directions (one going up, and one going down). I only want to plot the one going down.

I know that I can only show the negative axis to "hide" the positive bit of the plot, but I want to show the whole chart, but only have the one line:

Answer 1

Okay, I got the answer. Use nyquistplot instead of nyquist and set the option ShowFullContour to off:

% This is an example contour
G = tf(80, [1 9 30 40]);

h = nyquistplot(G);
setoptions(h, 'ShowFullContour', 'off');