-------- Original Message -------- Subject: size standardization in EFA Date: Wed, 7 Oct 2009 09:16:49 -0700 (PDT) From: Thomas DeWitt <[email protected]> To: <[email protected]> I want to hear opinions as to whether centroid size is a reasonable criterion for size standardization in EFA. Normally, size in EFA is standardized to the area of the first harmonic ellipse. Standardizing to ellipse area yields for the first harmonic quartet: A=1, B=C=0, and |D|<1, which is a tidy property. Is there any reason one method of size standardization should be preferred over the other? It seems if standardized to centroid size then principle components of the harmonic coefficients are more purely "shape variables". -Thom DeWitt >=))))(º> >=))))(º> >=))))(º> {|||||º> ^ ^ L L L L Dr. Thomas J. DeWitt, Associate Professor Departments of Wildlife & Fisheries Sciences and Plant Pathology & Microbiology Interdisciplinary Research Program in Ecology & Evolutionary Biology Texas A&M University 2258 TAMU College Station, TX 77843-2258 Tel. (979) 458-1684 (office) Tel. (979) 845-7522 (lab) Fax (979) 845-4096 E-mail [email protected] Web http://wfsc.tamu.edu/faculty/tdewitt/webpage.htm TAMU Map to DeWitt lab & office: http://www.tamu.edu/map/gifs/detail/FGHB.gif -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
