Bending of long slender organisms (or other structures) can be an important practical problem. Changes due to bending could dominate the results. Separating sets of landmarks into more rigid sublets can help as long as the endpoints of the subsets are homologous and not arbitrary or dependent on the bending of a particular specimen. The tpsUtil program has an "unending" option if one has a subset of points that one knows should be in a straight line. That would be difficult for larvae.
Note: I see you are using ver. 2.30 of tpsDig. Version 2.31 is current. I do try to keep fixing bugs so It can be useful to stay current. ____________________________________________ F. James Rohlf, Distinguished Professor, Emeritus. Ecology & Evolution Research Professor, Anthropology Stony Brook University -----Original Message----- From: Avi Koplovich [mailto:netbird.porta...@gmail.com] Sent: Tuesday, February 27, 2018 3:09 AM To: MORPHMET <email@example.com> Subject: [MORPHMET] Digitizing landmarks on live larvae Hi, I've started a new project and came to the point of marking fixed and semi landmarks. Not all pictures are satisfying, mostly because of the posture of the larvae during photographing (sometimes raising it's tail). So in order to reduce the noise by the animal posture, I thought it would be helpful to separate head and tail as was done in Levis et. al. 2016, Biol. J. Linn. Soc. I'm using the landmarks 1, 20 and 48 as fixed landmarks, and all the rest are semi landmarks. I'm not sure of using 20 and 48 as fixed landmarks, and I wonder if I can use landmark 40 as fixed landmark since it is restricted by both x (side line) and y (dorsal connection of the tail fin). Can/Should I use the eye as a fixed landmark for the head (i.e. can it interfere with interpreting the head contour)? Here is an example to show what I mean: https://drive.google.com/file/d/1iO7lCN3ZCtV7DF9vsczkb_EYoSli1Orr/view?usp=sharing I'll be happy if you can advise on that. Thank you, Avi -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org --- You received this message because you are subscribed to the Google Groups "MORPHMET" group. To unsubscribe from this group and stop receiving emails from it, send an email to morphmet+unsubscr...@morphometrics.org. -- MORPHMET may be accessed via its webpage at http://www.morphometrics.org --- You received this message because you are subscribed to the Google Groups "MORPHMET" group. To unsubscribe from this group and stop receiving emails from it, send an email to morphmet+unsubscr...@morphometrics.org.