How to add a secondary axis to a polarplot on matlab?

I would like to add a secondary radial axis to a polar graph in order to show the variation of two parameters as theta changes from 0 to 360 degrees. Any help would be much appreciated.

Answer 1

[Star Strider]

See if this does something similar to what you want:

t = 0 : 2*pi/177 : 2*pi;
a=linspace(0.3,0.5,178);
m=linspace(0.4,0.6,178);
figure(3)
ax = polaraxes;
hold on
polarplot(ax,t,a,'-b')
polarplot(ax,t,m,'-r')
ax.RColor ='blue';
ax.ThetaDir = 'counterclockwise';
ax.ThetaZeroLocation = 'bottom';
thetaticks([0:30:360])
thetaticklabels({'180','150','120','90','60','30','0','330','300','270','240','210'})
rlbl = sprintfc('%.0f',(0:2:6));                                % Radius Labels
text(ones(1,4)*1.8*pi, (0:2:6)*0.1, rlbl, 'Color','r')          % Label Radii

It does not plot separate radial grids (although that is not difficult to do). It is designed to produce something similar to yyaxis for a polarplot, here one curve and axis in blue and another curve and asxis in red

[Abraham Hartley]

Thank you,

I will give it a go. For interests sake, how would one go about plotting sererate radial grids?

[Star Strider]

My pleasure.

Here are grid lines that are not part of the original grid:

addgrid = [0.1; 0.3; 0.5]*ones(size(t));                        % Calculate Grid Lines At [0.1 0.3 0.5]
polarplot(ax, t, addgrid, '--k')                                % Plot Them

Experiment with the line style and radii to get the result you want.