-------- Original Message --------
Subject: Re: centroid size into cm
Date: Wed, 28 Jan 2009 02:59:30 -0800 (PST)
From: Stefan Schlager <[email protected]>
To: [email protected]
References: <[email protected]>
thank you Kim - and reporting the unit could be misinterpreted by
comparing the CSs of different configurations analogous to comparing
surfaces. (I had an actual case where an archeologist wanted to compare
the sizes of two different -non homologous - landmark configurations via
CS).
Stefan
morphmet schrieb:
-------- Original Message --------
Subject: Re: centroid size into cm
Date: Tue, 27 Jan 2009 08:22:40 -0800 (PST)
From: Kim van der Linde <[email protected]>
To: [email protected]
References: <[email protected]>
<[email protected]>
I think what he means is that centroid size is not a direct measure for
for example the surface of an object. It is a measure of the cumulative
distance of the landmarks to the centroid (which is not necessarily the
biological center of the object).
Kim
morphmet wrote:
Not sure what you mean by "original" configuration, but if CS were
independent of the configuration for which it is computed it wouldn't
be terribly interesting.
You don't give CS a unit of measure. It already has one though most
folks don't report it. If you are clever, though, you can take
advantage of the knowledge of its units and computation and come up
with compelling reasons for using, say, log(CS):
Mitteroecker, P, P Gunz, M Bernhard, K Schaefer, and FL
Bookstein. 2004. Comparison of cranial ontogenetic trajectories among
great apes and humans. JOURNAL OF HUMAN EVOLUTION 46, no. 6 (June):
679-697.
-ds
morphmet wrote:
-------- Original Message --------
Subject: Re: centroid size into cm
Date: Tue, 27 Jan 2009 07:17:54 -0800 (PST)
From: Stefan Schlager <[email protected]>
To: [email protected]
References: <[email protected]>
Centroid size is highly dependent of the original configuration and
giving it a unit of measure could be misleading - as the latter is
independent of the object in question.
Greetings
stefan
morphmet schrieb:
-------- Original Message --------
Subject: Re: centroid size into cm
Date: Tue, 27 Jan 2009 07:04:41 -0800 (PST)
From: Dennis E. Slice <[email protected]>
To: [email protected]
References: <[email protected]>
Centroid size has the same units as the coordinates with which it is
computed. If you have scaled your image to cm, then CS is in cm,
mm-mm.
CS from unscaled images are probably in pixels that are assumed to be
square.
Hmm, if you only had the specimen, say, a human in anatomical
position,
you could scale by anatomy and produce CS in, say, cubits.
-dslice
morphmet wrote:
-------- Original Message --------
Subject: centroid size into cm
Date: Tue, 27 Jan 2009 06:32:04 -0800 (PST)
From: Kassam Daud <[email protected]>
Reply-To: [email protected]
To: [email protected]
Crew
is it possible to convert centroid size values into some "commonly
known" unit of measure, for instance into centimetres? Assuming
one took pictures without setting any scale beside the organism.
kassam
--
Replies will be sent to the list.
For more information visit http://www.morphometrics.org
