Dear Mr. Ardón, Good question. Whenever we make shape comparisons in GM, be that via displacement vector or deformation grid (which is what you’re doing), we can typically only compare two shapes at a time. One shape is called the reference (or starting shape, in this case). This is the shape for which the grid would look “normal”; straight, equally spaced grid lines. The second is the target, where the grid is deformed to take this second configuration. If you want to compare two geographic groups, I would suggest setting one group’s mean shape to be the starting shape and the other group’s to the target; this will lead to the most direct comparison. I am not certain how easy this is to do in MorphoJ, though.
Hope this helps, James > On Oct 31, 2018, at 12:01 PM, Diego Ardón <diegoardon1...@gmail.com> wrote: > > Hello, my name is Diego and I'm currently undertaking a Master's program in > Mexico. One of my thesis project involves a geometric morphometrics study on > the shape of a freshwater fish which distributes across Central America. I'm > currently having trouble with a concept that will probably be very simple to > most of you, but which I haven't found a way to get my head around. > > I'm running a CVA on MorphoJ, dividing my dataset into two geographically > distinct groups. I run the test and change the type of graph to a "Warped > Outline Drawing". So now the graph is showing a "starting shape" which I > interpret as it being the average of all my landmark data (both geographical > groupings), however I'm not sure on how to interpret the "target shape". I > was expecting to have two "target shapes", one for each of the geographical > groupings. Could someone please help point out my misunderstanding and offer > me a way on how to interpret the "target shape"? > > Thank you, I'll be very thankful > > Diego Ardón > -- > 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.
