On Wed, 2 Aug 2006, Norman Gray wrote:
> Mark,
>
> On 2006 Aug 2 , at 12.32, Norman Gray wrote:
>
> >>>> think about whether you
> >>>> need to perform unit conversions for the quantity that you've
> >>>> identified to mean what you think it means...
Sounds to me like some standard library for handling all this system
conversion, units conversion, searching, etc, stuff is needed :-)
> I meant to add that unit conversions wouldn't be addressed by any
> sort of solution I'm talking about, but they're rather separate
> anyway, since unit specifications address how the value is
> represented -- and thus are to some extent syntactic -- rather than
> what it is. No?
In that sense a velocity (say) is a velocity is a velocity, and *all*
metadata describing it is syntactic, not just the units.
To say "velocity A and B are the same, but just measured in different
units" seems to me to be no different to saying "velocity A and B are
the same but just measured in different rest frames". In both cases, A
and B are representations of the same physical phenomenon. So I can't
immediately see any reason for treating units differently to any other
item of metadata. They are all needed if you want to be able to compare
two values.
David
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