[Fwd: Re: Fwd: [CF-metadata] units in cf standard names]

[John Caron]

There's some feeling here that the Calandar handling aspects of udunits are probably a mistake, that is, dont belong in a physical units package. They are adequate for simple cases, but we havent been all that interested in supporting all the complexities of Calendars. In the future, we might want to look to other packages for that functionality.

John

Jennifer M. Adams wrote:
> Steve Hankin brought to my attention a post to this group regarding  the 
> udunits library. I have just subscribed to this list in order to  post 
> the following reply:
> 
> GrADS uses the udunits library to get the time axis information for  
> netcdf files when the only available metadata is whatever is  contained 
> in the file itself.  The udunits library has some  limitations (e.g. 
> 365_day_calendar isn't supported), but it works  well enough. I spent 
> some time poking at the code a year or so ago  when looking into fixing 
> problems with no_leap time axes, and I found  a lot of sloppy and 
> complicated code I didn't want to have to  rewrite. I didn't feel it was 
> really worth fixing when it was much  simpler to just ask the user to 
> provide the right time start time and  increment for those types of data 
> files. Plus, I didn't want to have  to carry around a patch to an 
> external library for future releases.
> 
> Jennifer
> -- 
> Jennifer M. Adams
> IGES/COLA
> 4041 Powder Mill Road, Suite 302
> Beltsville, MD 20705
> jma at cola.iges.org
> 
> 
> On Oct 10, 2006, at 6:36 PM, Steve Hankin wrote:
> 
>> just in case this email slipped by -- GrADS uses udunits, doesn't it?
>>
>> From: Bryan Lawrence <b.n.lawrence at rl.ac.uk>
>> Date: October 10, 2006 4:11:20 PM EDT
>> To: Roy Lowry <rkl at bodc.ac.uk>
>> Cc: cf-metadata at cgd.ucar.edu
>> Subject: Re: Fwd: [CF-metadata] units in cf standard names
>>
>>> The choice of udunits was made by COARDS. We carry on with it for  
>>> COARDS
>>> compatibility. Are there any other similarly comprehensive and  flexible
>>> standards for interpreting units strings? I think the main benefit  
>>> is to
>>> provide a general syntax, and secondarily some associated software  
>>> for parsing
>>> and converting units.
>>
>>
>> Is anyone actually using udunits in anger with netcdf-cf data. If so,
>> how? (I'm not dissing the importance of syntax, and coards ... nor  am I
>> pushing a barrow for change here, just trying to understand exactly
>> where we are ...)
>>
>> Cheers
>> Bryan
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>>
>>
> 
> 
> 
> 
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