One expects some difference because the semilandmarks are moved and that will change the apparent size of the object. The change should not be very large unless the configuration of semilandmarks is such that they are moved greatly. This could happen it there are sharp corners along the outline. With my own examples the changes in centroid size were very small.
Were you using the default options of tpsRelw? Note: I don't recommend that you use the two "adjacent" options - they were an experiment and I plan to change or remove them in the next version. You should also not make the maximum number of iterations allowed a very large number - the results can degenerate. I could give a better comments if you sent me some example data so I could see what is happening. -------------------- F. James Rohlf, Distinguished Professor, Dept. Ecology & Evolution, Stony Brook University, Stony Brook, NY 11794-5345 > -----Original Message----- > From: morphmet [mailto:[EMAIL PROTECTED] > Sent: Monday, February 14, 2005 10:36 AM > To: morphmet > Subject: scale, sliding semilandmarks, tpsRELW > > Hello Morphometricians: > > I would like to post a question about centroid size and > sliding semilandmarks. When I use sliding semilandmarks in > tpsRELW I get very large values of centroid size. Much larger > than doing GPA with the same configurations but omitting the > sliding procedure. Why is this so? > > Thanks for feedback, > > Markus > _________________ > Markus Bastir, PhD > Email: [EMAIL PROTECTED] > Web: http://www.york.ac.uk/res/fme/people.htm > > > -- > 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
