You may also try looking at: Bookstein FL (1989) 'Size and shape': a comment on semantics. Systematic Zoology 38:173-180.
Marc Moniz -----Original Message----- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of [EMAIL PROTECTED] Sent: Tuesday, May 18, 2004 9:51 AM To: [EMAIL PROTECTED] Subject: Re: size correction & discriminant functions analyses Brett: Darroch and Mosimann (1985) is a frequently-cited paper that talks about scale adjustment for both PCA and CVA. They use "log-shape" data that are ln-transformed ratios. That paper should be a useful starting point. Darroch JN & Mosimann JE (1985) Canonical and principal components of shape. Biometrika 72:241-252. Good luck, Tim Cole At 10:09 AM 5/17/2004 -0400, you wrote: >Dear morphometrician, > >I have recently reviewed 3 genera of catsharks that display a great >deal >of morphological conservation within the genera, however, there is also >prominent sexual dimorphism present (profoundly so in some species). There >is quite a bit of shape variation between juveniles and adults, in one >genus in particular, but I think that the shape variation is being >obscured by the size component. > >I have a sizeable morphometric data set (# measures >> # taxa & >specimens) >and have used principal components analysis on the raw data to explore >shape variation within each of the genera (not between). The first >component was always a general component and accounted for more than >85-90% of the variation in most instances, therefore the bipolar >components only contributed relatively little to the overall shape >variation resulting in crowded PCA plots. > >The main reference I have used for the analyses to date has been >'Pimental. 1979. Morphometrics. The multivariate analysis of biological >data' however, it doesn't deal with size correction. Can anyone suggest a >review that deals with size correction, or can I convert my data to ratios >and then log transform the data? > >I am also looking for reviews of canonical discriminant functions >analysis >and stepwise discriminant function analysis in an attempt to quantitate >differences between species within a genus. > >Thanks for your help. > >Brett > >************************************ > Brett Human > Shark Researcher > 27 Southern Ave > West Beach SA 5024 > Australia > 61 8 8356 6891 > [EMAIL PROTECTED] > ************************************ > > > >== >Replies will be sent to list. >For more information see >http://life.bio.sunysb.edu/morph/morphmet.html. Theodore M. Cole III, Ph.D. Department of Basic Medical Science School of Medicine University of Missouri - Kansas City 2411 Holmes St. Kansas City, MO 64108 USA Phone: (816) 235 -1829 FAX: (816) 235 - 6517 e-mail: [EMAIL PROTECTED] www: http://c.faculty.umkc.edu/colet == Replies will be sent to list. For more information see http://life.bio.sunysb.edu/morph/morphmet.html. == Replies will be sent to list. For more information see http://life.bio.sunysb.edu/morph/morphmet.html.
