-------- Original Message --------
Subject: Re: common allometric components and residual shape components
Date: Wed, 7 Mar 2012 17:44:06 -0500
From: ejsch...@ucalgary.ca
To: morphmet@morphometrics.org
thanks, and i've got my figures now.
I'm also comparing appending the coordinate data with centroid size and
running the prcomp() in R to the output from MorphoJ, in which I regressed
PC1 (from residual data) against the regression scores of shape
coordinates vs centroid size. If they are the same or similar, then the
regression scores are the same or similar to the so called CAC, and PC1 of
size corrected data is equivalent to the so called RSC1.
eric
-------- Original Message --------
Subject: Re: common allometric components and residual shape components
Date: Wed, 7 Mar 2012 11:29:04 -0500
From: Aki Watanabe <awatan...@bio.fsu.edu>
To: morphmet@morphometrics.org
Hi Eric,
For R, you can use prcomp(), instead of princomp(). The former uses
spectral decomposition, so it doesn't give you an error when you have
more variables than specimens.
Cheers,
Aki
On Wed, Mar 7, 2012 at 10:54 AM, morphmet
<morphmet_modera...@morphometrics.org
<mailto:morphmet_modera...@morphometrics.org>> wrote:
-------- Original Message --------
Subject: common allometric components and residual shape components
Date: Wed, 7 Mar 2012 07:27:41 -0500
From: ejsch...@ucalgary.ca <mailto:ejsch...@ucalgary.ca>
To: morphmet@morphometrics.org <mailto:morphmet@morphometrics.org>
Hi,
I have a question about common allometric components and residual
shape
components, or CAC and RSC, and how RSCs relate to PCs generated
from
size-corrected data.
So, the CAC is a regression line, calculated using a pooled within
group
regression of coordinate data on size. And if so, is this line also
referred to as a pooled allometric vector? And will MorphoJ allow
one to
use this vector in a regression with another variable, such as the
RSC? Or
is it a better bet to obtain the allometric vector in another
program,
such as R.
Using the residuals from that regression and doing a PCA, the PC1
is the
same as the RSC? Is this correct? If so, MorphoJ will certainly do
this.
One more issue: doing PCA using R...I have problems with an error
about
having too many variables (relative to the number or rows, I
suppose). How
do I work around this in R?
Eric
U of Calgary
--
Aki Watanabe
Department of Biological Science
Florida State University
King Life Science Building
319 Stadium Drive
Tallahassee, FL 32306-4295
University of Chicago - AB '09
Biological Sciences and Geophysical Sciences
Website: http://sites.google.com/site/akinopteryx/home
Weblog: http://akiopteryx.blogspot.com/
