As to my knowledge, partial warps are not orthogonal, so only the complete set of them makes a sense to analyze. If you wish to reduce the morphospace dimensionality you better use relative warps. They are principal components of the partial warps and hence are orthogonal. You may select several first RWs, say 1st to 5th, which may appear enough to represent similarities among your objects. Cheers Igor
----- Original Message ----- From: morphmet <[EMAIL PROTECTED]> To: morphmet <morphmet@morphometrics.org> Sent: Wednesday, January 26, 2005 6:41 PM Subject: use of partial warps in DA/CVA > Dear all, > > I have a question concerning the use of partial warp scores in discriminant > analysis (DA)/CVA. I have an outline data, including a couple of true > landmarks and many sliding semilandmarks, on moth genitalia. I use this > data in order to test how well it applies in categorizing study specimens > into correct species (closely resembling each other in genitalia but not in > wing patterns) and I repeat this with several species groups. There are, > however, too many partial warps for the DA since I have only 20-40 > specimens for creating discriminant functions (the rest one-third of > specimens are used for cross-validation). For this reason, I selected only > those partial warp scores showing strong statistical differences between > the species in MANOVA. I got pretty nice results since also those specimens > that were not used in creating discriminant functions were classified > correctly. But is this correct? Can I select those partial warp scores that > differ in MANOVA and use them alone in DA/CVA? I could also reduce the > number of sliding semilandmarks, but since I use outline data with sliding > landmarks, this could possibly reduce the power of DA/CVA? > > I would be grateful for all advices, > > Marko Mutanen > University of Oulu > Finland > [EMAIL PROTECTED] > -- > 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
