[UDUNITS #IEB-391154]: Unit for 'bell' in udunits2-common.xml

Sander,

> In udunits2-common.xml there appears to be a definition for the logarithmic 
> unit for 'bell'. However, the symbol used for this seems to be 'BW' instead 
> of 'B'. Is there a rationale behind this or is this just a typo?

There's no definition of the unit "Bell" in the UDUNITS-2 database. This is 
because the Bell unit is meaningless by itself: it always has to be referenced 
to a reference level. This is why the Bell units that are in the database have 
one or more characters following the "B". The Bell units in the database are 
ones with well-known reference levels and symbolic abbreviations.

> Consistency-wise, the item below is Bm (and not BWm). Based on documents such 
> as  "Guide for the Use of the International System of Units (SI)" 
> <http://physics.nist.gov/cuu/pdf/sp811.pdf> I would expect just 'B' and 'Bm' 
> to be available.
> 
> I also checked, but there does not seem to be another symbol 'B' that would 
> conflict with using 'B' for bell.

Like I said, a "B" by itself would be meaningless. There would be no way to 
convert values in that unit specification to values in another, compatible 
specification.

You could add a Bell unit to the database as a local addition. I doubt that 
others would be able to use it, however, for the reason I gave.

> Best regards,
> Sander Niemeijer
> S[&]T, The Netherlands

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: IEB-391154
Department: Support UDUNITS
Priority: Normal
Status: Closed