-------- Original Message -------- Subject: Re: query [DA with discrete characters - the mod] Date: Wed, 7 Oct 2009 06:05:58 -0700 (PDT) From: [email protected] To: [email protected] References: <[email protected]> A "dirty trick" for carrying out discriminant analysis on non-continuous characters is Anderson's Canonical Analysis of Principal Coordinates (CAP). The idea is simply to run an initial Principal Coordinates Analysis, which can use any distance measure appropriate for your type of data, and then do a traditional discriminant analysis/CVA on the principal coordinate scores for the "first few" PCoA axes. You can do this in any software that includes PCoA and DA/CVA (e.g. R or Past), or you can use Anderson's special-purpose software "CAP" that includes a number of useful features: http://www.stat.auckland.ac.nz/~mja/Programs.htm I am not going to comment on whether CAP is a valid procedure or not, so don't shoot at me, but it does produce good-looking plots :-) Oyvind Hammer Natural History Museum University of Oslo
-------- Original Message -------- Subject: query Date: Wed, 7 Oct 2009 02:45:52 -0700 (PDT) From: Gabriele Salvo <[email protected]> To: [email protected] Hi all, I'm new to the field and I would like to receive a few suggestions. I have compiled a morphological character/species matrix including only discrete characters (presence/absence and multistate), which I would like to analyze in a phylogenetic framework. Since in my group of interest there is a species complex, I would like to use the relevant bits of the morphological matrix to visualize the species complex in morphological space. I have in mind a PCA kind of plot showing the different entities of the species complex with circles. Some will overlap completely, others less. I would also like to find out which are the most useful morphological characters for teasing the entities of the species complex apart. I have read some articles on traditional morphometrics and it appears that what I intend to do comes closer to a Discriminant Analysis, but I learn that this is mainly (only?) for continuous characters. Do you have any suggestions (also regarding the software that I could use)? Cheers gabriele ---------------------------------------------------------------------------------------------------------------------------------------------------- Gabriele Salvo PhD Student Institut für Systematische Botanik Universität Zürich Zollikerstrasse 107 CH-8008 Zürich SWITZERLAND e-mail: [email protected] tel: 0041 (0)44 634 84 18 -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
-- Replies will be sent to the list. For more information visit http://www.morphometrics.org
