Combining state coding

Mike Dallwitz miked at spider.ento.csiro.au
Tue Apr 20 23:05:08 CEST 1999


- From: Helen Coleman

> We have a large DELTA data set almost completed, and with the power of 
> hindsight we now see that some characters would serve us better with a 
> reduced set of more clearly defined states. For example in our #170, 
> flower head colour:
>
> #170. heads <colour>/
>        1. white/
>        2. cream <white with a hint of dull yellow>/
>        3. pale yellow/
>        4. yellow/
>        5. golden/
>        6. pink to purplish/
>        7. red/
>
> It would be desirable to be able to combine certain states thus:
>
> #170. heads <colour>/
>        1. white to cream/
>        2. pale yellow to golden/
>        3. pink to red/
>
> We are thinking of archiving the first coding format so that this more 
> detailed information can be used in natural language descriptions, but 
> the second, reduced format is preferable in Intkey.
>
> Is there a way to modify the coding in items to combine states? 
> (without having to do it manually?). Secondly, is there a way to 
> define key states in Intkey, as there is in the tokey directive file?

Neither of these can be done at present. We will eventually provide the 
first in the DELTA Editor.

I suggest retaining your current 7-state coding. Its greater separating 
power makes it better for Intkey as well as for natural-language 
descriptions. However, users must be made aware that they should select 
more than one colour if uncertain.

This principle is very important for the effective use of _any_ 
character in interactive identification, and we emphasize it in the 
online help in Intkey:

    The program then displays a list of character states, or a box for
    entering values such as lengths. Click on the state, or enter the
    value, that applies to the specimen, and press 'OK'. IF YOU ARE
    NOT SURE OF THE CORRECT STATE OR VALUE, DO NOT GUESS. Instead,
    click on more than one state, enter a range of values, or press
    'Cancel' and try another character."

You could further emphasize it for this particular character by changing 
the feature line to

    #170. heads <colour - see Notes>/

and providing a suitable character note. If the character is 
illustrated, you could add a text overlay such as:

    N.B. Select more than one colour if you are not sure.

This would have the additional advantage of drawing the user's attention 
to the general principle - users can, and often do, avoid looking at the 
general help.

Mike Dallwitz
CSIRO Entomology, GPO Box 1700, Canberra ACT 2601, Australia
Phone: +61 2 6246 4075   Fax: +61 2 6246 4000
Email: md at ento.csiro.au  Internet: biodiversity.uno.edu/delta/



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