How can I find the set of vertices of hexagons which are adjacent to a random point?
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Aravind Varma Dantuluri
on 10 Aug 2024 at 7:07
Commented: Aravind Varma Dantuluri
on 13 Aug 2024 at 2:19
I have a set of hexagons whose blue coordinates are known:
![](https://www.mathworks.com/matlabcentral/answers/uploaded_files/1750334/image.png)
I have a random red point and I need to know the 4 (in some cases it would be 3) points which are immediately adjacent to it. These points are contained in the black box shown for illustration.
I tried to sort the blue points by measuring distances but I keep getting extra points (shown by black arrows) or missing the required points.
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Accepted Answer
Matt J
on 13 Aug 2024 at 0:53
Edited: Matt J
on 13 Aug 2024 at 1:51
hex=[ 0 -1.0000
-0.8660 -0.5000
-0.8660 0.5000
0 1.0000
0.8660 0.5000
0.8660 -0.5000
1.7321 -1.0000
0.8660 -0.5000
0.8660 0.5000
1.7321 1.0000
2.5981 0.5000
2.5981 -0.5000
3.4641 -1.0000
2.5981 -0.5000
2.5981 0.5000
3.4641 1.0000
4.3301 0.5000
4.3301 -0.5000] %hexagon points
hex=unique(hex,'rows');
given=[1.2,-1];
pts=[given;hex];
DT=delaunayTriangulation(pts);
CL=DT.ConnectivityList;
idx=any(CL==1,2);
idx=setdiff(CL(idx,:),1);
nearest=pts(idx,:)
plot(hex(:,1),hex(:,2),'x', nearest(:,1),nearest(:,2),'o',given(:,1),given(:,2),'s');
legend Vertices Nearest Given
axis equal padded
More Answers (1)
Mario Malic
on 10 Aug 2024 at 11:04
Hi,
here's some code to give you an idea
X = rand(3,3);
Y = rand(3,3);
pts = [X(:), Y(:)];
distance = squareform(pdist(pts)); % symmetric matrix that contains distances between points
% distance between pt3 and all other pts
[~, idx] = sort(distance(:, 3));
closestPts = idx(2:5) % first one is distance between pt3 and pt3 so we ignore that
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