Dear Martin,

Sorry for not getting to this ticket sooner!

I'm not sure I agree with changing the ids with "spurious spaces". The problem 
is that when the names were first published they did accidentally contain 
spaces - the aliases were introduced to correct the mistake (in the same way as 
we would do for a simple spelling mistake). The versions of the names 
containing spaces had been around for quite a long time before they were 
noticed. "rate_of_ hydroxyl_radical_destruction_due_to_reaction_with_nmvoc" 
appeared in versions 28 - 36 of the standard name table, spanning a period of 
18 months in 2015-16. The other four appeared in versions 8 - 10 spanning a 7 
month period in 2008. It is possible that during those periods data files were 
written containing the erroneous names. To avoid invalidating such files I 
thought it was better to use aliases rather than just quietly delete the 
problem! I could of course simply delete the aliases if that is generally felt 
to be acceptable, but that would mean treating typos involving spaces 
differently from any other minor error that might crop up in standard names.

Regarding the other alias that points to two current names, this again was done 
to avoid possibly invalidating existing data files. The original name, 
surface_carbon_dioxide_mole_flux, contained no indication of sign convention 
and this was felt not to be satisfactory. That particular name dates back to 
pre-version 1 of the standard name table and the aliases weren't introduced 
until version 15, a period of at least 2006 - 2010. Data files could have been 
written during that period using either upwards positive or downwards positive 
as a sign convention and both would have been valid CF at the time. I support 
the idea of changing the schema to make this use of aliases valid - such a use 
case was probably not envisaged when the schema was created but the main aim 
should always be to preserve the original meaning of the data, not to 
accidentally change it by imposing a schema that is too rigid.

Best wishes,

Alison


-- 
You are receiving this because you are subscribed to this thread.
Reply to this email directly or view it on GitHub:
https://github.com/cf-convention/cf-conventions/issues/132#issuecomment-398455421

Reply via email to