# Octave pzmap: format poles and zeros

This question is linked to this one:

Octave rlocus: format ploles and zero

I am using the Octave command pzmap but the size of the markers of the poles and zeros by default are very hard to see on the computer screen. I have looked at the pzmap.m file and changed the line:

h = plot (pol_args{:}, zer_args{:});


to

h = plot (pol_args{:}, zer_args{:},"markersize", 20);


but there is no effect.

and putting the markersize parameter in an actual code is not valid:

num=[1 3];
den=[1 5 20 16 0];
sys=tf(num,den);
pzmap(sys,"markersize", 20) %not valid


Any suggestion?

The line you edited in pzmap.m is almost correct. You need to provide a "markersize" option for both poles and zeros.

Original plot:

After changing line 116 of \share\octave\packages\control-3.1.0\pzmap.m

h = plot (pol_args{:}, "markersize", 10, zer_args{:}, "markersize", 10);


Edit: to modify linewidth:

h = plot (pol_args{:}, "markersize", 10, "linewidth", 5, zer_args{:}, "markersize", 10, "linewidth", 5);


• Great. Is there a way to make the markers appear bold i.e. by changing the line weight? – user11206 May 14 '18 at 8:33
• @user11206 Appended it to answer. Check the edit. – Vicente Cunha May 14 '18 at 19:30
• Great! It works fine in Octave. – user11206 May 15 '18 at 5:19

Try the following code,

num=[1 3];
den=[1 5 20 16 0];
sys=tf(num,den);
pzmap(sys) h=pzmap(sys)

hh = findobj(gca,'type','line');
for jj=2:length(hh)
set(hh(jj),'MarkerSize',12,'MarkerEdgeColor','red','LineWidth',5);
end


source

And the result is,

• Great. Is it possible to make the markers more pronounced as in "bold". – user11206 May 10 '18 at 9:44
• With the command: set(h.allaxes.Children(1).Children, 'MarkerSize', 20), I am getting the error message: error: matrix cannot be indexed with . – user11206 May 10 '18 at 9:48
• @user11206 check the edited answer – Hazem May 10 '18 at 9:53
• pzplot is not yet part of Octave. Are you testing the code in Matlab or Octave? – user11206 May 10 '18 at 14:18
• Done. Thank you for the suggestion. stackoverflow.com/questions/50285757/… – user11206 May 11 '18 at 5:48