I am examining variation in butterfly morphological data, and decided to learn about geometric morphometrics. In addition to reading about the theory behind, I have been using tps. To understand better what the different programs are doing, I have tried to derive different variables from the outputs, and used them in other statistical packages. I am feeling more confident about what I have learned, yet I have a couple of questions and I would greatly appreciate your help with them:
* The variables used in the relative warp analysis (tpsRelW) correspond to the procrustes distances? If so, can these distances becalculated from the aligned matrix that has the landmark coordinates after doing the procrustes? * Does the plot of relative warps correspond to a PCA biplot, that used as input the procrustes distances? Where can I find the PCA scores for the landmarks? The scores for the specimens corresponde to the relative warp matrix? * I have tried all of the above, and used the procrustes distances in other statistical packages. In general the PCA results look similar BUT not identical. So I am wandering whether this is a result of my incipient knowledge of procrustes methods and tps or perhaps that the programs use a different algorithm. I would like to thank you in advance for your kind help. Have a Merry Christmas and a Happy New Year! ===== Alexandra Herrera Martinez Estudiante de MaestrÃa [EMAIL PROTECTED] Laboratorio Dr. Richard Thomas Departamento de BiologÃa Universidad de Puerto Rico San Juan,PR 00931-3360 P.O. Box 23360 U.S.A. _________________________________________________________ Do You Yahoo!? InformaciÃn de Estados Unidos y AmÃrica Latina, en Yahoo! Noticias. VisÃtanos en http://noticias.espanol.yahoo.com -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
