-------- Original Message --------
Subject: Re: Resistant Fit Procrustes Superimposition
Date: Fri, 3 Jun 2011 05:05:10 -0400
From: andrea cardini <[email protected]>
To: [email protected]
Dear Ruth,
you can do a superimposition based on a subset of landmarks using Morpheus
and the demote landmarks command. It's in a different context but you can
find an example here:
Cardini A., Diniz Filho J. A. F., Polly P. D., Elton S., 2010 -
Biogeographic analysis using geometric morphometrics: clines in skull size
and shape in a widespread African arboreal monkey. A. M. T. Elewa (Ed.),
Springer-Verlag Publishers, Heidelberg, Germany.
Available at:
http://sites.google.com/site/hymsfme/drandreacardini/ac-publications
RF, I seem to remember, is implemented in GRF-ND. I managed to run this old
DOS program in XP using DOSBox 0.73 (freeware).
You could try different superimpositions and then compare the pairwise
shape distances using a simple matrix correlation (don't do the test,
though; check r only and the scatterplot of distances) or just looking at
the PCA scatterplots. This may give you a crude idea of the magnitude of
the differences depending on your choice of superimposition.
I would also check with theoreticians what the implications are of these
different superimpositions in terms of shape spaces.
Good luck.
Cheers
Andrea
At 15:44 02/06/2011 -0400, you wrote:
-------- Original Message --------
Subject: Re: Resistant Fit Procrustes Superimposition
Date: Thu, 2 Jun 2011 11:27:09 -0400
From: Philipp Mitteröcker <[email protected]>
To: [email protected]
Dear Ruth,
Depending on the assessed structure and the aim of your study, it might
be a solution to superimpose all landmarks just using a subset of
landmarks (in your case probably all landmarks except the problematic one).
Best wishes from Vienna,
Philipp
Am 02.06.2011 um 15:54 schrieb morphmet:
-------- Original Message --------
Subject: Resistant Fit Procrustes Superimposition
Date: Wed, 1 Jun 2011 01:21:37 -0400
From: Ruth Flatscher <[email protected]>
To: [email protected]
Dear all,
I am a botanist working with an object whose landmark distribution is
not ideal, i.e. one single landmark is quite far away from the others.
In addition, based on my observations I assume that this same landmark
is also more variable in its position to the others. Performing an
"ordinary" Least Squares Procrustes fit, I fear I am facing a "Pinocchio
effect". Therefore, I have thought of using Resistant Fit Procrustes
Superimposition. Does anybody of you have experience in it, and is there
any software available which is able to calculate it?
I have also thought of other solutions, like a Procrustes fit omitting
size standardization. Alternatively, I could calculate two
pseudolandmarks on either side of this distant landmark, in order to
make it less isolated from the others. What do you think about these
possibilities?
I would be very glad if somebody could help me out with some suggestions.
Best wishes, and greetings from Vienna,
Ruth
Mag. Ruth Flatscher
Department of Evolutionary and Systematic Botany
Rennweg 14
A-1030 Vienna
email: [email protected] <mailto:[email protected]>
___________________________________
Dr. Philipp Mitteroecker
Department of Theoretical Biology
University of Vienna
Althanstrasse 14
A-1090 Vienna, Austria
Tel: +43 1 4277 56705
Fax: +43 1 4277 9544
email: [email protected]
homepage: http://theoretical.univie.ac.at/people/mitteroecker
Dr. Andrea Cardini
Researcher in Animal Biology
Dipartimento di Biologia, Universitá di Modena e Reggio Emilia, via Campi
213, 41100, Modena, Italy
tel: 0039 059 2055017 ; fax: 0039 059 2055548
Honorary Fellow
Functional Morphology and Evolution Unit, Hull York Medical School
University of Hull, Cottingham Road, Hull, HU6 7RX, UK
University of York, Heslington, York YO10 5DD, UK
Adjunct Associate Professor
Centre for Forensic Science , The University of Western Australia
35 Stirling Highway, Crawley WA 6009, Australia
E-mail address: [email protected], [email protected],
[email protected]
Webpage: http://sites.google.com/site/hymsfme/drandreacardini
Datasets:
http://ads.ahds.ac.uk/catalogue/archive/cerco_lt_2007/overview.cfm#metadata
