Hi, As always, I am confident that the creator of EFA3D, James Rohlf, will confirm (or not :) I have used the program quite a bit. As a general rule, curves should be registered in a common orientation before you can run EFA. This can be achieved in various ways, e.g. by using a common baseline (plane in 3D) or 3 or more landmarks. I always apply a least-squares alignment to landmarks "attached" to the curves and then run the EFA, as was proposed in various papers. The program accepts input files with multiple specimens, so long as they are preceded with a header that indicates the number of points. In your example the header indicates one subject (hence the second 1) with a curve of 60 points in 3 dimensions (=180 xyz values), no missing data (0). The header follows the nts format, described in detail in other programs such as GRF-ND or Morpheus. I am not aware of any other (free) program that computes a 3D EFA.
Hope this helps, Martin Martin Friess Département Hommes, Natures, Sociétés Musée de l'Homme - Paris morphmet wrote: > Dear All > > I am interested in using EFA3D to calculate Fourier coefficients for some > curve data taken on human crania. However, this program only has limited > supplementary information as yet so I have a few questions: > > 1) Do all homologous curves first need to be placed in the same frame of > reference given three common landmarks before co-efficients can be > computed? > > 2) Can I then place all homologous curves in the same input file even if > they each have varying number of points making them up? > > 3) If anyone has used this program before perhaps you can spell out what > the first line of the input file refers to: i.e. 1 1 180 0 DIM=3(that's > presumably dimensions?) > > Perhaps some people have used alternative programs for such analysis? I am > aware of several 2D versions but no other 3D ones. > > Any comments, suggestions and advise are gratefully accepted! > Many thanks in advance > Noreen > > -- Replies will be sent to the list. For more information visit http://www.morphometrics.org
