Plotting Rotated Error Ellipses

I have successfully been able to plot my error ellipse around a point but I haven't been able rotate the semi-major axis from the X-axis by a specified angle. The function I am using orients the ellipse to the x-axis but I need to represent the ellipse rotated by a specified angle. The function I am using is:

function plotEllipse(a,b,C)

% range to plot over    
%------------------------------------    
N = 50;     
theta = 0:1/N:2*pi+1/N;

% Parametric equation of the ellipse
%   
%----------------------------------------    
state(1,:) = a*cos(theta);      
state(2,:) = b*sin(theta);      
% Coordinate transform (since your ellipse is axis aligned)     
%----------------------------------------     
X = state;     
X(1,:) = X(1,:) + C(1);     
X(2,:) = X(2,:) + C(2);      
% Plot     %----------------------------------------     
plot(X(1,:),X(2,:));     
hold on;     
plot(C(1),C(2),'r*');     
axis equal;     
grid; 
end

Any suggestions are welcomed.

Answer 1

[Matt Fig]

Please go back and format your code using the {}Code button.

EDIT Thanks for making your code readable!

Change this line:

plot(X(1,:),X(2,:));

to this:

L = plot(X(1,:),X(2,:));

and return L from your function.

Then from the command line, do:

L = plotEllipse(2,3,[5 9]);
rotate(L,[0 0 1],30)  % Rotate the ellipse 30 degrees.

[Cory Smith]

Worked perfectly thank-you