Thank you for your fast answer.
I'll continue to mark the landmarks as separated sublets, i.e. head and
1. Is it ok to use landmark 40 (intersection of the side line and the
dorsal connection of the tail fin) as a common mark point to create a comb
fan for both tail and head?
2. Another question: Is this landmark 40 can be treated as fixed
landmark as it is restricted by both x and y axis?
3. Can I use landmarks 20 (tail tip) and 48 (head tip) as fixed
landmarks in an ontogenetic experiment?
4. Last question: Can/Should I use the eye as a fixed landmark for the
head (i.e. can it interfere with interpreting the head contour)?
p.s. I saw your forum message here on updating tpsdig 2.31 and already
On Wednesday, February 28, 2018 at 8:51:39 PM UTC+2, f.james.rohlf wrote:
> 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-----
> Sent: Tuesday, February 27, 2018 3:09 AM
> Subject: [MORPHMET] Digitizing landmarks on live larvae
> I've started a new project and came to the point of marking fixed and semi
> 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.
> 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:
> I'll be happy if you can advise on that.
> Thank you,
> MORPHMET may be accessed via its webpage at http://www.morphometrics.org
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