RE: Do you need to know size for Procrustes superimposition?

[morphmet_moderator]

----- Forwarded message from "F. James Rohlf" -----

Date: Sat, 24 Nov 2012 07:21:01 -0500
From: "F. James Rohlf"
Reply-To: ro...@life.bio.sunysb.edu
Subject: RE: Do you need to know size for Procrustes superimposition?
To: morphmet@morphometrics.org

No, you do not have to provide information on the actual sizes if all you care about is variation in shape. However, because allometry is so common, knowing size is often useful for understanding some of the variation in shape.

 

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F. James Rohlf, John S. Toll Professor, Stony Brook University

The much revised 4^th editions of Biometry and Statistical Tables are now available:

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From: morphmet_modera...@morphometrics.org [mailto:morphmet_modera...@morphometrics.org]
Sent: Saturday, November 24, 2012 1:39 AM
To: morphmet@morphometrics.org
Subject: Do you need to know size for Procrustes superimposition?

 

----- Forwarded message from Patrick Kennedy -----

Date: Wed, 21 Nov 2012 21:19:26 -0500
From: Patrick Kennedy
Reply-To: Patrick Kennedy
Subject: Do you need to know size for Procrustes superimposition?
To: "morphmet@morphometrics.org"

Hi,

 

I'm completely new to morphometrics, so sorry if this question seems a bit basic/obvious to those in the know!

 

I have a roughly 400 individuals, which are divided into nine different groups, and I want to find out whether these different groups have different mean shapes. I'm going to use MANOVA here. But to get to that point, I'll need, of course, to do Procrustes superimposition. Each group was photographed at a different time, so the scale differs each time. I have a reference to scale each group to, but it would be a long and tedious process to go through each individual setting the scale. Is this necessary? Could I just run the Procrustes superimposition as it is with individuals photographed at different distances? 

 

In other words (and sorry if this seems a stupid question), do I need to tell the software the actual/relative sizes of the specimens in order to do the superimposition? I can't really see why you would need to (though I am a humble undergraduate just beginning here, so I thought I would check).

 

Many thanks to anyone who can advise. 

 

Patrick 

patrick.kenn...@bnc.ox.ac.uk

 

 

----- End forwarded message -----

 

 

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