Maarten,
I think I understand. You're fortunate in being "grandfathered-in", so to
speak.
I just don't want to go down the road of adding support for all kinds of
different entities. I'm a bit sensitive in that regard. :-)
Regards,
Steve Emmerson
On Wed, Jan 7, 2015 at 10:31 AM, Maarten Sneep <maarten.sneep at knmi.nl>
wrote:
> On 07-01-15 17:10, Steve Emmerson wrote:
>
>> Jonathan,
>>
>> I think you meant to say that if a physical quantity has a different
>> dimensionality (not unit), then we have to give it a different name.
>>
>> In my opinion, what's needed in this case is a package that understands
>> co-ordinate transformations -- in order to convert, for example, values
>> in units of "1e15/cm2" to values in units of "mol/m2". This is a rather
>> simple example and Maarten makes a good (though not yet convincing to
>> me) argument for simply modifying the UDUNITS database. One can imagine,
>> however, more complicated cases in which simple unit conversions are not
>> possible (e.g., converting between altitude and pressure). Such a
>> package would be easily capable of handling Maarten's conversion.
>>
>
> The only argument I'm making is that 'molecules' is available as a unit
> equivalent to 'avogadros_number-1' (which is the case with the current
> release of UDUnits). People who use 1/cm2 when they (implicitly) mean
> molecules/cm2 get what they deserve IMHO.
>
> As soon as you have molecules/cm2, then UDUnits can handle the conversion
> as is. For other densities, say an aerosol particle count, the conversion
> to mol is never needed, and number densities are fine (and a look at the
> standard_names will confirm this).
>
> So right now I'm not asking anything, as the most important scaled alias
> for 'mol' is available. This will ease the transition to mol/m2 quite
> significantly. It would be good to help the transition from photons to mol
> (photons) as well, which was a request that started this whole discussion
> in the first place.
>
> Does this make the argument clearer?
>
> Best,
>
> Maarten Sneep
> --
> KNMI
> T: 030 2206747
> E: maarten.sneep at knmi.nl
> R: A2.14
>
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