Overlap between N circles
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Hello everyone I have an excel file with 2 columns (x and y) and 2111 rows. What my program does as far now is to : call the file from matlab, place all the couples (xi,yi) on the graph and construct one circle for each point of the excel matrix
clc
close all
clear all
DataSelect='celapossofare';
[v,X,vX]=xlsread('celapossofare.xlsx');
x=v(:,1);y=v(:,2);
plot(x,y,'.');
r = x*0 + 1000;
CIP=circles_new(x,y,r);
Now I would like to calculate the overlapping of this circles (that has as centre xi, yi).
Can someone help me?
[EDIT] CHIARA'S "ANSWER" MOVED HERE:
what I did is the following code
d2 = (x2-x1)^2+(y2-y1)^2;
d = sqrt(d2);
t = ((2*r)^2-d2)*(d2);
if r <= d <= 2*r
A = 2*r^2*acos(d2/(2*d*r))-1/2*sqrt(t);
elseif d > 2*r
A = 0;
else % d < r
A = pi*r^2;
end
My problem Is very stupid but I just started to prgram in matlab.
I don't know How to take x,y from a matrix that I have in excel
4 个评论
Sara
2014-6-4
Do you need the points where the circles intersect or the area of the overlap?
chiara
2014-6-5
Roger Wohlwend
2014-6-5
Do you want to know just the size of the area or do you want to know exactly where it is so that you could highlight it in a diagram for example?
chiara
2014-6-5
采纳的回答
Roger Wohlwend
2014-6-5
0 个投票
Construct a grid. Calculate for each point the distances to the circle centers. All points whose distances to the circle centers are smaller than the radiuses belong to the overlapping area.
3 个评论
John D'Errico
2014-6-5
Of course, this will be highly inexact, being equivalent to a very simple integration, essentially rectangle rule. Note that an exact answer was asked for (not that that will be possible.)
Roger Wohlwend
2014-6-5
编辑：Roger Wohlwend
2014-6-5
Yes, I admit it is not very exact. Perhaps a better solution is taking paper and a pencil and calculate a formula.
Image Analyst
2014-6-5
With a fine enough grid, it can be made as close as is needed. Perhaps it's just an exercise in numerical analysis. She could decrease the grid spacing until the answer "levels out" and becomes relatively stable.
更多回答（2 个）
Sara
2014-6-5
0 个投票
If you have the mapping toolbox, you can use polybool.
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