Plotting a set of rings using a single function
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How to plot a set of rings (see the Figure below) using a single function, i.e., through the use of "for" loop?
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Accepted Answer
VBBV
on 14 Aug 2020
Edited: VBBV
on 14 Aug 2020
See also the m file for the code
clearvars close all
x = -100:0.5:200;
y = -100:0.5:200;
r = 50;
theta = 0:0.1:360;
for i = 1:length(x)
for k = 1:length(y)
if x(i) == 0 & y(k) == 0
for j = 1:length(theta)
xxc1(j) = r*cos(theta(j)) + x(i);
yyc1(j) = r*sin(theta(j)) + y(k);
end
plot(xxc1,yyc1,'b'); hold on axis([-100 200 -100 200]);
end
if x(i) == 0 & y(k) == 100
for j = 1:length(theta)
xxc2(j) = r*cos(theta(j)) + x(i); yyc2(j) = r*sin(theta(j)) + y(k);
end plot(xxc2,yyc2,'b'); hold on axis([-100 200 -100 200]);
end
if x(i) == 100 & y(k) == 0
for j = 1:length(theta)
xxc3(j) = r*cos(theta(j)) + x(i); yyc3(j) = r*sin(theta(j)) + y(k);
end
plot(xxc3,yyc3,'b'); hold on axis([-100 200 -100 200]);
end
if x(i) == 100 & y(k) == 100
for j = 1:length(theta)
xxc4(j) = r*cos(theta(j)) + x(i); yyc4(j) = r*sin(theta(j)) + y(k);
end
plot(xxc4,yyc4,'b'); hold on axis([-100 200 -100 200]);
end
end
end
More Answers (1)
Walter Roberson
on 14 Aug 2020
r = 50;
viscircles([0 0; 0 2*r; 2*r 0; 2*r 2*r], [r;r;r;r], 'color','k', 'linewidth', 1)
If you need to be able to plot fewer or more circles, you need to explain the pattern.
5 Comments
Walter Roberson
on 14 Aug 2020
You have used fft() which is primarily for 1D signals. But for most of the x values, for any given x, there are either 0 or 4 associated y values. When there are multiple y values for a single x, then that is not a 1D signal.
It is possible to use fft() on a 2D signal, in which case it applies the transform along a single dimension. But if you were doing that then you would have to be very careful about what length() of the 2D signal would mean; most of the time length() would be wrong for that code.
So, what will F be, exactly: a 2D array that has circles drawn in it? If so then use insertShape https://www.mathworks.com/help/vision/ref/insertshape.html or use one of the techniques described at https://matlab.fandom.com/wiki/FAQ#How_do_I_create_a_circle.3F
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