How to find the number of point inside the graph?
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Hello,
- I have made a graph and inserted many random points.
- I marked the point manually in orange color for points outside the graph and green color for points inside the graph
- I wonder how can we calculate the number of points in green color automatically using only MATLAB code?
Thank you in advance
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/150343/image.png)
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Answers (1)
Andrei Bobrov
on 20 May 2015
Edited: Andrei Bobrov
on 20 May 2015
x = [0,7, 18, 37,47,54,57.5,59,61.5,69,87,95,99,103,110]'/110; % Let this
y = [0, 15,43,53,42,20,7,0, 37, 61,56, 40.5, 24, 6, 0]'/61; % is arrays - your data
f = griddedInterpolant(x,y,'pchip'); % old MATLAB: pp = interp1(x,y,'pchip','pp');
% f = @(x)ppval(pp,x);
xx = rand(100,1);
yy = rand(100,1)*1.3; % points for check
t = f(xx) - yy > 0;
plot(0:.001:1,f(0:.001:1));grid on
hold on
plot(xx(t),yy(t),'g*');
plot(xx(~t),yy(~t),'r*');
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