Hi, I would consider doing a short reliability test on five specimens for each individual for the single point landmarks and the curves. This shouldn't take long and will give you an idea as to whether the landmarks are reliable or not. Ideally this should be done before adding the landmarks to the data set.
Sincerely, Hadas On Sun, Oct 9, 2016 at 5:56 AM, Helmi Hadi <helmih...@gmail.com> wrote: > Dear Morphometricians, > > I have a weird problem and I was hoping someone could help me on this. > > I have the same CT bone (n=400) with 14 landmarks (2 Single point and 12 > sliding) larndmarked in IDAV Landmark by three different individuals > following a figure key table. Each individual landmarked 100+ different > bones. The figure key table has the shape of the bone, with the landmark > locations and the order of landmarking. All users were briefed by a single > person (user1) on how to extract the bone and landmark. All three > individuals were present throughout the entire procedure but the bone > segmentation and landmarking process was conducted individually. > > When I combine all the data, I noticed that PC1 and PC2 graph has two > clusters. The effect is about 55% (as detailed in the eigenvalues below) > After further checking the classifiers in MorphoJ, the source of the > clustering is one person (user1) landmarked it is slightly differently > compared to the other two. I have checked the outliers tab and no glaring > outliers exists. As the sample size is big, the curve seem to be quite > normal. > > Eigenvalues % Variance Cumulative % > 1. 0.01603351 55.674 55.674 > 2. 0.00496222 17.230 72.904 > 3. 0.00224594 7.799 80.703 > 4. 0.00121085 4.204 84.907 > 5. 0.00076858 2.669 87.576 > ... > > How to interpret the results for this kind of data? Things which come to > my mind are: > > 1. Maybe the bones for user1 are different compared to the other two users. > Or > 2. User1 thinks the landmark location slightly different compared to > others. > Or > 3. User2 and 3 could not locate the landmark locations of user1. > Or > 4. The landmarks selected are unreliable. > > Ideally I would need few other people relandmark the entire set, but it is > not possible to do it now. Can anyone help shed some light on what is the > probable cause? Thank you. > > > Kind regards, > > Helmi Hadi, PhD > School of Health Sciences, Universiti Sains Malaysia, > 16150 Kubang Kerian, Kelantan, MALAYSIA > > > -- > 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.
