# Draw Lines between Points in MATLAB

• MATLAB

## Main Question or Discussion Point

Hi,

I have a matrix V, which is a 5-by-2 matrix, where each row represents a point in the xy-plain. How can I connect these points together in MATLAB, please?

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jhae2.718
Gold Member
plot(V(:,1),V(:,2)) should do it, if I remember my matrix slicing.

plot(V(:,1),V(:,2)) should do it, if I remember my matrix slicing.
Ya, I tried this, but it does not work. It connects just between three points. I need to connect between all points to form a closed graph, starting from a point and ending at the same point.

Thanks

jhae2.718
Gold Member
It only plots three points? I think you should be able to get a connected graph by appending the start point onto the matrix (getting a 6x2) and then using plot.

It only plots three points? I think you should be able to get a connected graph by appending the start point onto the matrix (getting a 6x2) and then using plot.
Thank you very much. It is now working perfectly.

jhae2.718
Gold Member

If I want to extend it to 3D, is it straightforward to do that?

jhae2.718
Gold Member
You should probably be able to do something similar with plot3() for lines in R3.

You should probably be able to do something similar with plot3() for lines in R3.
That indeed works, but this connects all the points together. Actually, in 3D I just want to connect the adjacent points only. How can I do that?

jhae2.718
Gold Member
That indeed works, but this connects all the points together. Actually, in 3D I just want to connect the adjacent points only. How can I do that?
I'm not sure what exactly you mean by this...

I'm not sure what exactly you mean by this...
Neither do I. But basically, V is a matrix that contains the vertices of a polytope, and I want just to connect the adjacent vertices not all together. I am not sure how to know what are the adjacent vertices from V.

Thanks

jhae2.718
Gold Member
You may have to break the matrix up into matrices such that plot3 will produce the lines connected the way you want.

Another option is to look on the file exchange and see if there's anything you can use there. http://www.mathworks.com/matlabcentral/fileexchange/

You may have to break the matrix up into matrices such that plot3 will produce the lines connected the way you want.

Another option is to look on the file exchange and see if there's anything you can use there. http://www.mathworks.com/matlabcentral/fileexchange/
Ok, I will. Thank you.

jhae2.718
Gold Member
I think there may be a file on the exchange that will do what you want, otherwise I'm afraid I don't know of a built in function that will do what you want on only one call.