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Create coordinates on a convex hull

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Kwek Lawrence
Kwek Lawrence on 12 Sep 2019
Edited: Bruno Luong on 12 Sep 2019
I have a convex hull, defined by
k=convhull(x,y)
P=[x(k),y(k)]
kS=polyshape(P)
kP=perimeter(kShape)
How can I divide the perimeter of the convex hull into n (e.g. 500) equal distance/lengths, and find the respective coordinates?

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Accepted Answer

Bruno Luong
Bruno Luong on 12 Sep 2019
Edited: Bruno Luong on 12 Sep 2019
% test data
xy=rand(100,2);
P=xy(convhull(xy),:);
d=[0;cumsum(sqrt(sum(diff(P).^2,2)))];
xyi=interp1(d,P,linspace(0,d(end),501)); % first point ~= last point
plot(P(:,1),P(:,2),'or',xyi(:,1),xyi(:,2),'b.-');

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More Answers (1)

Bjorn Gustavsson
Bjorn Gustavsson on 12 Sep 2019
Perhaps this function is overkill, but to me it seems as if this FEX-contribution should help:
xy2sn, I don't know if it is the functionality of xy2sn or the sn2xy that most resembles your request.
Perhaps either of these contributions solves your problem better:
arclength, interparc. But one of these should get you at least 90% of the way.
HTH

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