Classification, clustering, and phylogeny estimation
Wed, 25 May 2005 22:23:00 -0400
There are many methods that have been proposed. The simplest is to express
them as ratios of some measure of size - which gets back to the original
question as there are many ways to express size. The sum of all the
measurements is a pretty unusual choice but it often may not matter much in
practice because the measurements are usually very highly correlated.
F. James Rohlf, Distinguished Professor & Graduate Program Director
State University of New York, Stony Brook, NY 11794-5245
> -----Original Message-----
> From: Classification, clustering, and phylogeny estimation
> [mailto:[log in to unmask]] On Behalf Of leo horseman
> Sent: Wednesday, May 25, 2005 10:03 PM
> To: [log in to unmask]
> I do not have a citation for you; however, I am interested in
> the question.
> I must admit to being baffled. Why include size measurements
> in your analysis at all, unless somehow the measurement of
> shape is derived from the size measurement. If you've
> measured only bone lengths, which surely would vary greatly
> in size, then how did you arrive at a shape measurement?
> >From: Richard Wright <[log in to unmask]>
> >Reply-To: "Classification, clustering, and phylogeny
> > <[log in to unmask]>
> >To: [log in to unmask]
> >Date: Mon, 23 May 2005 12:06:54 +1000
> >This is a question about size and shape in morphometric studies.
> >I have a series of measurements of bone lengths in individuals that
> >vary greatly in size. I want to consider similarities and
> >between the individuals solely in terms of shape. To remove
> >in absolute size I have taken each individual, summed all the
> >measurements for that individual, and then divided each
> measurement by that sum.
> >This is an intuitively simple method. Some years ago I read a
> >recommendation about using it. Now an editor is asking me to cite a
> >reference to the use of the method. Unfortunately I cannot recollect
> >where I saw it advocated.
> >Can anybody help?
> >I know that there are various alternative methods for
> eliminating size
> >in multivariate morphometric work, such as eliminating the first
> >principal component if that is one of general size. However
> my question
> >is not about the competing merits of size/shape methodologies in
> >general. This is a specific request for a citation of the
> approach outlined above.