polar plots axis limits

How does one set the axis limits in polar plots?

Answer 1

[Patrick Kalita]

Well, unfortunately there's no direct way to do it. But you can cheat (yay! cheating!). Let's say you know you want to have the radial dimension go out to 2. You can add a line of constant radius and then make it invisible:

t = 0 : .01 : 2 * pi;
P = polar(t, 2 * ones(size(t)));
set(P, 'Visible', 'off')

Now you can add the data you actually want to plot:

hold on
polar(t, sin(2 * t) .* cos(2 * t), '--r')

[Eric T]

Cool trick. It is the multiple-year, uncorrected, lack of obvious basic functionality like this in many Matlab functions that pushes people toward Python.

[Jorge]

@Eric Agreed. The lack of coherence between MATLAB function is a shame. In this case, we have a plotting function where not only xlim or ylim just don't work, you can't also for instance use 'LineWidth' as argument as you do with plot(). But if you do p = polar(), p.LineWidth property does in fact exists! It is just that someone could't be bothered to add property pairs to polar() itself in more than a decade!

[Richard Garner]

Thanks for your responses. But I have to take a little exception to your criticism of Matlab. I don't know of any software that is perfect, including Python. I used Python as well as Matlab and find a lot of "issues" with it. My feeling is that alot of people migrate to Python because it's free. Of course, it obviously has ALOT of nice functionality that rivals or even supercedes Matlab. But also that doesn't match up to Matlab. Anyway, just my "2 cents" worth.

Answer 2

[Steven Lord]

With the introduction of the polaraxes function in release R2016a you now have access to properties like ThetaLim and RLim.

[Richard Garner]

Thanks for that. I did not notice. Guess I hadn't made polar axis plots in awhile.

Answer 3

[Mazin Mustafa]

If you want to plot something such as antenna pattern for e.g. -40 dB to 0dB you may use the following code:

data = 10*log10(abs(data)./max(abs(data))); % Normalize your data

range = -40; % Choose the minimum value in dB

data(isnan(data)) = range;

data = data - range;

data = data./max(data);

data(data < 0) = 0;

polar(theta,data,'k')

view([90 270])

set(findall(gcf, 'String', '0' ),'String', ' ');

set(findall(gcf, 'String', ' 0.2' ),'String', num2str(range-(range*0.2)) );

set(findall(gcf, 'String', ' 0.4' ),'String', num2str(range-(range*0.4)) );

set(findall(gcf, 'String', ' 0.6' ),'String', num2str(range-(range*0.6)) );

set(findall(gcf, 'String', ' 0.8' ),'String', num2str(range-(range*0.8)) );

set(findall(gcf, 'String', ' 1' ),'String', '0 dB' );

[rhashaan omar]

could you explain? I'm trying to plot a graph of antenna radiation from -30 to 10 dB. I have a table of the values I digitized using an onlne website, but I can't scale my graph to match the original graph.