Re: [MORPHMET] Sliding Semilandmarks

Hi all, I just stumbled across this discussion a bit too late, so I am joining the party after everybody has left. > If the semilandmarks slide a lot relative to the local curvature, they > get off the curve. Of course, they can be projected back, but the > following trick often is sufficient:

Re: [MORPHMET] Sliding Semilandmarks

As Michael described, the average shape configuration affects the sliding when used as reference for the TPS; the final configurations thus are sample-dependent. However, if the curves/surfaces are covered densely enough by the semilandmarks (e.g., to avoid that a semilandmark can slide away

Re: [MORPHMET] Sliding Semilandmarks

Ariadne Schulz ha scritto: Hello all, I'm having a bit of a semilandmark problem. I'm working on 3D surfaces with semilandmarks. (Profuse thank yous to Emma for writing the scripts for that.) The issue I'm having I think is occurring in the sliding. When I do

Re: [MORPHMET] Sliding Semilandmarks

Andrea, I like to think of semilandmark sliding as iteratively finding fitted (predicted) values for the generalized linear model fit described by Gunz et al. (2005) (equation 4), and updating coordinates by these values until there is no more meaningful change (with regard to an acceptable

Re: [MORPHMET] Sliding Semilandmarks

Will update and try again. That sounds - without being too hopeful - like it might solve my problem. If not, I'll come back with better details. I would also like the clarification on the point Andrea has asked about. That sounds like a concerning issue for what I'm trying to do with this.

Re: [MORPHMET] Sliding Semilandmarks

Mike, does this mean that, in general, the position of the semilandmarks is strongly sample dependent, which would mean that also the shape distances might change remarkably despite the fact one has the same number of points on exactly the same surface? Say that I have two samples, A and B. I

Re: [MORPHMET] Sliding Semilandmarks

Ari, If you are using geomorph, you might want to update it via GitHub. Just a few days ago we updated the software with some bug fixes for surface points (one bug fix was for assuring non-arbitrary directions in PC planes for tangents of surface points). If you are unsure how to do that,