Clear Filters
Clear Filters

How to plot circle with direction?

21 views (last 30 days)
Megha
Megha on 10 Sep 2019
Commented: michael on 20 Jan 2021
I wish to plot a circle with direction of its motion.An exmaple is attached below.Path_Ideal.jpg
I wish to get around 5-10 arrows per circle (that can be chnaged as per our need).
Below attached matlab.mat file is the data file.
The code goes like:
subplot(2,2,[1 3])
h1 = plot(x, y, '-','Color','b','LineWidth',2);
Now I dont know how to put 5-10 arrows showing direction.
Can anyone help?

Answers (1)

Bruno Luong
Bruno Luong on 10 Sep 2019
Edited: Bruno Luong on 10 Sep 2019
2D version. adapt to your need
% circle parameter
r = 5;
cx = 0;
cy = 0;
cfun = @(tt) [cx+r*cos(tt); cy+r*sin(tt)];
xy = cfun(linspace(0,2*pi,361));
close all
hold on
plot(xy(1,:),xy(2,:),'b');
% arrows parameters
m = 10; % number of arrows
h = 0.1*r; % height
w = 0.1*r; % width
dir = -1; % 1 anticlock, -1 clock
a = [-w/2 0 w/2;
-dir*h 0 -dir*h];
for k=1:m
tt = 2*pi*k/m;
R = [cos(tt) -sin(tt);
sin(tt) cos(tt)];
xy = cfun(tt)+ R*a;
plot(xy(1,:),xy(2,:),'b');
end
axis equal
  5 Comments
Megha
Megha on 11 Sep 2019
I have tried the following code, but arrows are too close to each other, in this case, to see the dirction of motion of circle.
rMag = 0.5;
lenTime = length(x);
% Indices of tails of arrows
vSelect0 = 1:(lenTime-1);
% Indices of tails of arrows
vSelect1 = vSelect0 + 1;
% X coordinates of tails of arrows
vXQ0 = x(vSelect0, 1); % x last removed
% Y coordinates of tails of arrows
vYQ0 = y(vSelect0, 1); % y last removed
% X coordinates of heads of arrows
vXQ1 = x(vSelect1, 1); % x first removed
% Y coordinates of heads of arrows
vYQ1 = y(vSelect1, 1); % y first remove
% vector difference between heads & tails
vPx = (vXQ1 - vXQ0) * rMag;
vPy = (vYQ1 - vYQ0) * rMag;
% add arrows
h2 = quiver (vXQ0,vYQ0, vPx, vPy, 0, 'b'); grid on; hold off
axis equal
michael
michael on 20 Jan 2021
I'w suggest to set
X = 10; % this is step size - each 10th point will have a vector
vSelect0 = 1:X:(lenTime-1);

Sign in to comment.

Categories

Find more on Thermal Analysis in Help Center and File Exchange

Community Treasure Hunt

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

Start Hunting!