MATLAB: How to plot circles around centre points

faqplotplotting

Hi, I woild like help with my plot. Each point p2…p9 (with p7 omitted) are cetnre points of circles of radius 250 and I would like to know how to include the circle in this plot to show their edges.
p1=zeros(1,1); 
p2= 1i*500;
p3= 2i*500;
p4= p1+500*(cosd(30)+(1i*sind(30)));
p5= p2+500*(cosd(30)+(1i*sind(30)));
p6= p3+500*(cosd(30)+(1i*sind(30)));
p8= p5+500*(cosd(30)-(1i*sind(30)));
p9= p6+500*(cosd(30)-(1i*sind(30)));
s=[p2,p3,p4,p5,p6,p8,p9];
figure, scatter(real(s),imag(s));grid;
Also in p5 I have some random points within the circle radius (that may also exceed the radius) and I would also like to know how to add these on the plot
      U_rad=rand(100,1)*(289-35)+35; 
      U=rand(100,1)*360;
      U_pos=(p5+U_rad.*(cosd(U)+1i*sind(U)));

Best Answer

ajk1, try this:
clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear all;
workspace;  % Make sure the workspace panel is showing.
format short g;
format compact;
fontSize = 20;
p1=zeros(1,1);
p2= 1i*500;
p3= 2i*500;
p4= p1+500*(cosd(30)+(1i*sind(30)));
p5= p2+500*(cosd(30)+(1i*sind(30)));
p6= p3+500*(cosd(30)+(1i*sind(30)));
p8= p5+500*(cosd(30)-(1i*sind(30)));
p9= p6+500*(cosd(30)-(1i*sind(30)));
s=[p2,p3,p4,p5,p6,p8,p9];
x = real(s);
y = imag(s);
theta = 0 : 0.01 : 2*pi;
radius = 125;
% Plot all the circles with a radius of 125
for k = 1 : length(x)
  xCenter = x(k);
  yCenter = y(k);
  thisX = radius * cos(theta) + xCenter;
  thisY = radius * sin(theta) + yCenter;
  % Plot cross hairs at center
  plot(xCenter, yCenter, 'r+', 'MarkerSize', 15, 'LineWidth', 2);
  hold on;
  % Plot circles around the center
  plot(thisX, thisY, 'b-', 'LineWidth', 2);
  fprintf('Plotted circle #%d at (%.1f, %.1f)\n', k, xCenter, yCenter);
end
axis equal;
% xlim([0 20]);
% ylim([0 20]);
grid on;
xlim([min(x)-radius, max(x)+radius]);
ylim([min(x)-radius, max(y)+radius]);
xlabel('X', 'FontSize', fontSize);
ylabel('Y', 'FontSize', fontSize);
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