Andrey,
It is unreasonable to expect the numbers will match perfectly between these two
software packages, as the way in which they perform the operations differs.
First, MorphoJ uses Full Procrustes fit, whereas the TPS series, geomorph, and
others use Partial Procrustes fitting. That will make a difference.
Second, there may be additional differences in in how the superimponsed
specimens, and thus the consensus, is aligned relative to the X-Y coordinate
system. Some packages allow one to rotate the consensus and aligned specimens
to their principal axes post-superimposition. That too could lead to
differences.
Dean
Dr. Dean C. Adams
Professor
Department of Ecology, Evolution, and Organismal Biology
Department of Statistics
Iowa State University
www.public.iastate.edu/~dcadams/<http://www.public.iastate.edu/~dcadams/>
phone: 515-294-3834
From: Andrey Lissovsky [mailto:andlis...@gmail.com]
Sent: Tuesday, October 31, 2017 9:26 AM
To: MORPHMET <morphmet@morphometrics.org>
Cc: andlis...@gmail.com; volk...@yandex.ru
Subject: Re: [MORPHMET] Procrustes fit
Thank you, Andrea
I understand that difference should be tiny, so something goes wrong. I enclose
one of my tps files. Usually I check dots and commas, so the reason is probably
in some different way..
It is possible that I am mixing up menu items.. Last time I use this software,
the labels were different.
Now I use:
In MorphoJ: Preliminaries -- New Procrustes fit -- Align by principle axes
then: Export dataset -- Procrustes coordinates
In TPS Relw: Actions -- Consensus
then: File -- Save -- Aligned specimens
Is this ok? Should these chains lead to the same results?
On Tuesday, October 31, 2017 at 5:04:56 PM UTC+3, alcardini wrote:
Andrey, the last time I checked this (last July, I believe), differences
between MorphoJ and TPSRelw were tiny and negligible. I compared MorphoJ
with R in the last days, and again differences were tiny.
The first thing I'd check is whether there's an issue with commas vs
dots as decimal separators.
If you send me the tps file, I can give a quick look.
Cheers
Andrea
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