MATLAB Answers

Random dots to make a circle

2 views (last 30 days)
This code works excellent to make a circle with randomized dots. My problem now is that I want a inner circle were these randomized dots can't be placed. So it will be like this
but have I drawn a circle.

Accepted Answer

Alan Stevens
Alan Stevens on 12 Apr 2021
Try something like
n = 1000;
t = 2*pi*rand(n,1);
Ri = 1;
Ro = 2;
r = Ri + (Ro - Ri)*rand(n,1);
x0 = 0; y0 = 0;
x = x0 + r.*cos(t);
y = y0 + r.*sin(t);
plot(x,y,'.b')
  2 Comments
Alan Stevens
Alan Stevens on 12 Apr 2021
How about
n = 2000;
t = 2*pi*rand(n,1);
Ri = 1;
Ro = 3;
r = Ro*rand(n,1);
x0 = 0; y0 = 0;
x = x0 + r.*cos(t);
y = y0 + r.*sin(t);
xoffset = 1;
yoffset = -0.5;
theta = 0:pi/180:2*pi;
xi = xoffset + Ri*cos(theta);
yi = yoffset + Ri*sin(theta);
plot(x,y,'.b')
hold on
fill(xi,yi,'w')
Note that, in order to get a uniform distribution of dots in a circle you need to choose R^2, not R, randomly (though this might not be important for your application, and I've not bothered to do that in the listing here).

Sign in to comment.

More Answers (0)

Tags

Products


Release

R2021a

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!