On Fri, Dec 20, 2013 at 12:00:22AM +0100, Felix Höfling wrote:
Such an attribute seems useful to ensure backwards compatibility in
the future. Otherwise, we could only extend the set of units in
future versions (and could have no contradicting symbols like hour
and Planck's constant).
The selection of non-SI-units in udunits appears a bit random, I'm
not sure whether we should stick verbatim to this library. For the
SI base and derived units, everything is fine though. We could
restrict to this set of units, which would be denoted by the value
"SI" for the system attribute. However, I'm afraid that many people
will dislike the idea to strictly stick to SI.
Other non-SI units may be added later (with appropriately extended
values of the system attribute).
As an alternative, we may give up direct interoperability with
udunits. Then, the current status would still be a useful
description of units which IMO covers most of the research with
molecular data in physics, chemistry, and biology. Maybe udunits
could even receive an update to support the missing symbols.
I'll be on vacation from tomorrow on, so please go ahead and choose
whatever appears more practical.
The attribute has been added. "SI" is thus taken :-)