Types of data

[Bernie Hyland.]

At 09:52 AM 11/24/1999 -0500, you wrote:
>>One of the data types that I would like to see modeled is a "matrix type"
>>data type.  Consider the leaf shape.  When I made up my DELTA data set,
>>I turned leaf shape into *3* characters -- one for leaf width, one for
>>the position of the widest shape, and a 3rd for the contour of the
>>sides.  (narrow, broad; ovate, obovate; rounded, parallel).  As the
>>basis for this division, I used the IAPT plain shape chart -- a two
>>dimensional representation.
>>
>>When you have a shape that varies from narrowly ovate to broadly obovate --
>>how can you model that in *one* character?  Variance from narrowly ovate
>>to narrowly obovate is possible just as variance from narrowly ovate to
>>narrowly obovate.
>>
>>You would define the data type by number and size of dimensions.  (Two
>>would probably be sufficient for most cases).
>>
>
>Of course, the IAPT shapes are not "real", they are conventions (the actual
>circumscription of the various shapes was decided at a meeting back in the
>'50s, I think).  As affording a communication device, the IAPT shape chart
>is excellent, and exactly what is needed (see below), as a means for
>measuring the world, it is definitely inferior to metrics such as
>millimeters and degrees.  The states, the 0s and 1s, of phylogenetic
>analyses, are treated far more as IAPT shape charts than as the results of
>measured and analysed variation for my liking.  Ideally - and I stress
>"ideally" - basic taxonomic data should be metric-type data (and images of
>things like pollen surface, perhaps wood anatomy) linked to specimen,
>rather as with d.n.a., where a sequence is deposited in GenBank and lnked
>to a specimen.  I am not suggesting that all our taxonomic work should be
>so anchored, but I am suggesting that far more than at present should be so
>treated.  Many morphological data sets consists of little more than
>unsubstantiated assertions about the world.  If, however, somebody asked me
>for a flora treatment of some 'well" understood group for N. Amerias, I
>would probably have no reasonable alternative (because one's life is
>limited...) than to use whatever communication conventions exist for what I
>am looking at.  (However, if a group had been monographed following more
>ideal standards, think how easy it would be to produce local accounts of
>variation, not to mention distribution maps, etc., etc.)
>
>And thinking of things like terms used in describing organisms, there
>certainly seems room for either synonymy tables and/or for more IAPT-type
>conventions.  This is particularly true of genus- and family-"level"
>descriptions in plants - for teaching purposes, I am reading descriptions
>of genera and families in an edited compendium, and there may be three or
>four words for what is arguably the same thing, or terms that acutally make
>it more, not les, difficult, to get to grips with the basic variation.
>
>
>Peter S.
>
>
THANKS FOR BRINGING REALITY INTO THE DISCUSSION.
I HAVE ONLY JUST JOINED THIS GROUP, SO I AM NOT PREPARED TO TRUMPET MY
THOUGHTS TO THE WHOLE WORLD AT THIS STAGE.
---------------------------------------------------------------------------
bernie.hyland at tfrc.csiro.au
Bernie Hyland,
CSIRO - Plant Industry,
Box 780,
ATHERTON 4883
Queensland, Australia.

Ph 07 40918805 Int. 61 740918805

FAX 07 40918888 Int. 61 740918888