-------- Original Message -------- Subject: Re: Prediction of landmark coordinates from other landmarks Date: Sun, 16 Jan 2011 17:22:10 -0500 From: Fabio de Andrade Machado <[email protected]> To: [email protected] I think that your second suggestion is very interesting. I would only suggest that you perform some kind of permutation analysis to access the significance of your PLS axes (25 seams to many). You could also perform some kind of cross-validation process to see how good the reconstructions are and if they are within-limits or digitalization error or if simply they are better than other method. cheers, Fabio Citando morphmet <[email protected]>:
-------- Original Message -------- Subject: Prediction of landmark coordinates from other landmarks Date: Fri, 14 Jan 2011 12:30:21 -0500 From: Pierre Guyomarc'h <[email protected]> To: [email protected] Dear morphometricians, I’m trying to use geometric morphometrics to predict the coordinates of a group of landmarks from another group of landmarks (of the same individual). The goal is to predict human facial skin features from bony morphology. As I’m no mathematician or statistician, I have some difficulties to evaluate the integrity of my methods. After short discussion with some morphometricians, I heard different opinions and advices. That’s why I’m submitting my questions more largely by throwing this bottle to the sea! What do you think of: -Method 1: predict each 3D coordinate of the unknown landmarks (group 2) from the PCs of a PCA ran on the known landmarks (group 1) through multivariate regressions. -Method 2: use best covariating groups of landmarks through PLS analysis and use the scores and PCA to predict the 3D coordinates of group 2. This methodology has been proposed at the 4th Meeting of Junior Scientists in Anthropology (Freiburg im Breisgau, March 2010). The proceedings are available at http://www.freidok.uni-freiburg.de/volltexte/7603/ and my contribution is at p.84. Feel free to consult it if you have time. A more complete description of this method is exposed. -Method 3: I would be really grateful if you can find me a third method! I’m open to all comments, even negative ones since they are constructive… Thanks! -- Pierre Guyomarc'h (PhD Student) Université Bordeaux 1 - UMR 5199 PACEA (CNRS) /Anthropology of Past and Present Populations/ (A3P) Av. des Facultés, Bât B8 - 33405 Talence cedex http://www.pacea.u-bordeaux1.fr/
-- Fabio de Andrade Machado Laboratorio de Herpetologia/Morfometria Museu de Zoologia da USP Av. Nazaré, 481, Ipiranga São Paulo, SP, 04263-000 Brazil +55 11 61658120 +55 11 82631029 -- Fabio de Andrade Machado Laboratorio de Herpetologia/Morfometria Museu de Zoologia da USP Av. Nazaré, 481, Ipiranga São Paulo, SP, 04263-000 Brazil +55 11 61658120 +55 11 82631029
