Set new origin in polar coordinates

Hi, I have a set of data in polar coordinates (r, theta). The default origin for matlab is (0,0). How I can change the origin to other points, such as (0,3)?

Thanks a lot.

[darova]

Can you plot data in cartesian system?

Answer 1

[Ameer Hamza]

One of the easiest ways I can think of is to convert the points from polar to cartesian, do the translation, and then convert back to polar. For example

r = 1;
theta = linspace(0, 2*pi, 100);
translate = [0 3];

x = r*cos(theta) + translate(1);
y = r*sin(theta) + translate(2);
r_trans = hypot(y, x);
theta_trans = atan2(y, x);
polarplot(theta_trans, r_trans)

Original:

Translated:

[Jiong Yang]

Thank you very much, Ameer. Your anwser solves my problem!