MATLAB: Is there a way to move the r-axis tic labels in a polar plot to another theta angle

polar plot

I have some results that are plotted on my polar plot, but the r-axis labels are interfering with some of the data. Can I move the r-axis tic labels to another theta rotation?

Best Answer

Use the polaraxes property RAxisLocation.

t = 0 : .01 : 2*pi;
h = polarplot(t, sin(2*t).*cos(2*t), '--r');
ax = ancestor(h, 'polaraxes');
ax.RAxisLocation = 180;

Related Solutions

MATLAB: How to label the R-axis in a polar plot

In R2016a and later releases, after having created a polar axes (via the "polaraxes" function directly or as a result of creating a polar plot via the "polarplot" function), you can get the "RAxis" property of that polar axes. The "RAxis" object has a property named "Label" that contains a "Text" object, which has a property named "String". For details about the "RAxis" property, refer to the following link:

www.mathworks.com/help/releases/R2016b/matlab/ref/polaraxes-properties.html#property_RAxis

To modify the r-axis label, you can adapt the following example code:

ax = polaraxes;
ax.RAxis.Label.String = 'My Label';

The "RAxis" property is a Numeric Ruler. To further manipulate the r-axis, you can modify the Numeric Ruler Properties of "ax.RAxis". For details, refer to the following link:

https://www.mathworks.com/help/releases/R2016b/matlab/ref/numericruler-properties.html

MATLAB: Theta marked in radians for ezpolar

polarplot uses polaraxes whereas expolar creates a pseudo-polar-plot on regular Cartesian axes. The ThetaAxisUnits property is not available with Cartesian axes. Instead, the theta ticks are added as text objects.

I recommend using polaraxes unless you have a very good reason not to.

To convert the theta ticks in the expolar plot to radians, you'll have to identify which text objects are the theta ticks and then convert them to radians.

This demo uses fractions to label the theta ticks.

ezpolar(@(t) 1+3/2*sin(2*t), [0, 2*pi])
ax=gca;
% Get all text objects
h = findall(ax, 'type', 'text');
% Loop through each text object.  If it appears to be a 
% theta tick label, convert it to radians. 
existingTicks = 0:30:360;  % List existing theta ticks
existingTickStr = strsplit(num2str(existingTicks)); 
for i = 1:numel(h)
    if ismember(h(i).String, existingTickStr)
        [num,denom] = rat(str2double(h(i).String)/180);
        if num==0 || denom==1 
            h(i).String = sprintf('%d\\pi', num/denom);
        else
            h(i).String = sprintf('^{%d}/_{%d} \\pi', num, denom);
        end
    end
end

For more simpler decimal labels, replace the inside of the loop with,

if ismember(h(i).String, existingTickStr)
    h(i).String = sprintf('%.2f',str2double(h(i).String)*pi/180);
end

Best Answer

Related Solutions

MATLAB: How to label the R-axis in a polar plot

MATLAB: Theta marked in radians for ezpolar

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