polar plot to create circular shape with varying radius

Hi Everyone,

I'm new to polar plotting and I'm struggling to sucesfully plot what I'm after.

I want to polar plot a random variable around an origin of my choice. I have tried to do this through the following code:

k = round(rand(1,50)*10)+10;
Th = linspace(0,2*pi,50);
Rho = k.*sin(Th);
figure
polar(Th,Rho)

However, this isn't quite working. As all the values are positive it's cramping the plot in the top 2 quadrants. Please see attached plot for what I mean. I have sketched the kind of plot I am after (apologies for how rough this sketch is) but any ideas would be realy appreciated.

Thanks everyone!

Answer 1

[Star Strider]

Plotting the sine function in a polar plot will produce one circle in the upper half of the polar axes.

To get the sort of plot you want, do this:

figure
polar(Th,k)

[William Gray]

Hi,

Thank you for this, a simple change but it gives me exactly what I was after!

[Star Strider]

As always, my pleasure!

Answer 2

[infinity]

Hello,

How about if you change a bit like this

clear
close all
% k = round(rand(1,50)*10)+10;
k = round(rand(1,50));
Th = linspace(0,2*pi,50);
% Rho = k.*sin(Th);
Rho = k.*sin(Th)-10;
figure
polar(Th,Rho)

[William Gray]

Hi,

Thanks for the answer this helps! Ive found from the script however that the 'randomness' of the values appear slightly stunted, I think because the rounding of k just gives zero's and ones. I've managed to plot what I was after below with Star Strider's answer but again, thank you for the help.