How to get the length of a spline in Matlab (cscvn)

[pettyTips]

Hello,

i'm searching for a method do get the length of a spline in 3D.

I'm refering to a closed thread (thread575-207328).
The member "cibachrome" wrote:
"The Spline Toolbox contains a function CSCVN that will hand you the total length as the last value of the arc sequence."

Can you tell me which arc sequence have been talked about?
I looked at the "breaks" parameter of the spline-object (created with cscvn) which contains as many values as given points.
But the last value can not be the total length of my spline.

Anbody can help me?
Thanks!

pettyTips

 

[GregLocock]

Well, to be honest the help, and a quick experiment, don't agree with cibachrome.

So if you had a matrix of x y and (perhaps) z coordinates how would you find the total length of the vector?





Cheers

Greg Locock


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[GregLocock]

Sorry not vector, 2 or 3d path represented by those points?

Cheers

Greg Locock


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[pettyTips]

Hey Greg,

Thanks for your answer!
I found another approximating solution:
I'm interpolating between the points, for example with square interpolation.
I connect the sampled points and the n interpolated points.
The length of my spline is the accumulated length of the parts.

Anja

 

[GregLocock]

And that's how I'd do it.

Cheers

Greg Locock


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[IRstuff]

And that's the general approach:

http://en.wikipedia.org/wiki/Curve#Lengths_of_curves

TTFN

FAQ731-376