-------- Original Message --------
Subject: Re: Visualise linear Measurements
Date: Mon, 2 Apr 2012 10:01:18 -0400
From: Dean Adams <[email protected]>
To: [email protected]
Carlo,
If one has truss-like measurements, there is a lovely paper in the white
book (Advances in Morphometrics 1996) by Carpenter et al. that uses MDS
to convert trusses back to coordinates. Dennis Slice has implemented
this approach in Morpheus, and it is quite user-friendly.
However, if your measurements are not interconnected in a truss-like
manner, things are not as rosy I am afraid. To visualize shapes from
linear distances, one requires information on the relative positions and
orientations of each linear distance with respect to the others.
Unfortunately, this information is not recorded in the distances
themselves, so one would have to make various assumptions and arbitrary
choices in this regard. As such, any visualizations should be treated
with extreme caution. Using characterized shapes (as was done in DeGusta
and Vrba) may be one way to go, but even these are only as good as the
assumptions of positional correspondence that one makes. Generally,
visualizations from such data cannot be made (which is one reason why
morphometrics moved towards landmarks).
Best,
Dean
--
Dr. Dean C. Adams
Associate Professor
Department of Ecology, Evolution, and Organismal Biology
Department of Statistics
Iowa State University
Ames, Iowa
50011
www.public.iastate.edu/~dcadams/
phone: 515-294-3834
On 4/2/2012 8:15 AM, morphmet wrote:
-------- Original Message --------
Subject: Re: Visualise linear Measurements
Date: Fri, 30 Mar 2012 03:08:08 -0400
From: Carmelo Fruciano <[email protected]>
To: [email protected]
I would like to visualisize bone morphological variation along PC
scores of multiple linear measurements. Those measurements are not all
interconnected -as could be ideal for a truss- and they were
collected using traditional calliper. Based on the correlation matrix I
can always see that PC1 highly correlates with the overall bone length
but I would like to see this variation like we could do in geometric
morphometrics with TPS.
Is there anyone having experience visualising objects from measurements?
The idea will be to go from linear measurement back to raw
coordinates as long as we can find spatial correspondence (I can trace
back the "approximately" exact position of what I measured on the bone).
I double checked the literature and I find only a visualisation example
-I guess manual drawing- in DeGusta & Vrba (2003) Journal of
Archaeological Science 30: 1009-1022, Fig.4 page 1018.
Any suggestion on software or statistical methods would be really
appreciated.
Dear Carlo,
I'm not sure if this is of any help in your particular case but you
might find interesting the following chapter:
Carpenter KE, HJ Sommer III, LF Marcus. 1996. Converting truss
interlandmark distances to Cartesian coordinates. In: LF Marcus, M
Corti, A Loy, G Naylor, DE Slice, eds. Advances in morphometrics. NATO
ASI Series A: Life Sciences, Vol. 284. New York: Plenum Publ., pp.
103-111.
Best,
Carmelo
