-------- Original Message --------
Subject: Re:urgent:separating the shape from the size
Date: Sat, 10 May 2008 07:09:37 -0700 (PDT)
From: thimacek <[EMAIL PROTECTED]>
To: morphmet <morphmet@morphometrics.org>
Ali,
By using geometric morphometrics, you are already separating "size" and
"shape" most, if not all of the time. If you used Landmark methods
(digitization followed by GPA), you'll have come to a number of 'Partial
Warps' and possibly 'Relative Warps', in addition to the Centroid Size.
The centroid size is a measure of size, while the Partial Warps are the
variables containing the Shape information. It should be noted that all
Partial Warps should be analyzed together, as each one of them alone
normally have no biological meaning per se.
The Relative warps are a sort of PCA (principal component analysis) done
on the Partial Warps, and as such one may be able to draw conclusions
by analyzing only the first among them, which represent larger amounts
of the sample's total variation.
If you want to look for correlation between size and shape - i.e.
allometry - you may make a multivariate regression using Centroid Size
(the size variable) as the independent variable and the Partial Warps
(all of them, which together represent shape) as dependent variables. If
you're making your analysis in 2D, you can do this using the TPSRegr
program by Rohlf.
I hope this helps!
Thiago
>
>
> -------- Original Message --------
> Subject: urgent:separating the shape from the size
> Date: Sat, 10 May 2008 04:53:11 -0700 (PDT)
> From: ali mahmood
> Reply-To: [EMAIL PROTECTED]
> To: morphmet@morphometrics.org
>
>
>
> Dear Friends
>
>
>
> Thank you for your kind help, I send before a question regarding the
> correlation between the the *size* of face and dental arch in geometric
> morphometric means ,and I received the answer from some Friends as the
> told me that I need to use the *centroid size* for both of them to
> calculate the correlation for the *size * ,but no one answer my question
> regarding the correlation between the *shape *of the face and dental
> arch (because I would like to separate the* size* from the *shape, *so
> what I need to calculate for the_ face_ and then to the_ dental arch_ to
> be used as variables in the correlation for the *shape*?
>
>
>
>
>
> Ali R Al-khatib
>
>
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