Hi,
I have a question about the analysis of semi-landmarks. Which is
typically analysed after the thin-plate spline plus registration routine?
A) The final coordinates of the semi-landmarks analysed as if they
started as regular landmarks, or
B) The distances, normal to the outlines, between the final
semi-landmarks and the outlines.
Best regards,
Ben
p.s. Have both been used?
-----Original Message-----
From: morphmet [mailto:[EMAIL PROTECTED]
Sent: 26 May 2005 14:26
To: morphmet
Subject: Re: Morphometric analysis
Dear Catherine,
You should use the PW scores matrix in all subsequent analyses of GM data
using multivariate methods.
By the way, your mollusk shells would provide an interesting application for
the still little explored "semilandmark" approach developed by Fred
Bookstein
(and implemented by Jim Rohlf in the TPSRelw program).
Hope this helps.
With best regards,
On Thu, 26 May 2005 08:06:56 -0400, morphmet wrote
> I'm a first year Ph.D student in the Ecology and Evolution
> Department at Leeds University, England. I'm studying a cline in
> morphotype in the inter tidal snail Littorina saxatilis which
> suggests there may be speciation in progress. I am very interested
> in using geometric morphometrics to quantify the variation in shell
> shape of the snails, although my knowledge of the field is limited
> at this stage.
>
> I have taken the route of landmarks and I am using the software TPS.
> I plan to use PCA/DFA in an attempt to discriminate between the
> morphotypes. However, I am unsure whether to use the Partial warp
> scores matrix, Relative warps score matrix or Weight matrix from the
> TPSRelw program in the analysis.
>
> I would be grateful for any advice.
>
> Catherine Sinfield
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