[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Fwd: Re: [Fwd: UTM file]]


>Date: Fri, 25 Feb 2005 14:10:11 -0600
>From: Christine Molling <address@hidden>
>Organization: UCAR/Unidata
>To: Steve Emmerson <address@hidden>,
>To: Tom Whittaker <address@hidden>
>Subject: Re: [Fwd: Re: [Fwd: UTM file]]

The above message contained the following:

> What am I trying to accomplish?  Merely express time in units that have 
> a one-to-one relationship with calendar time.

Good luck.  Units of the physical quantity "time" don't have a simple,
one-to-one relationship with calendar time.  Believe me, I've beaten 
my head against this issure more times than I can remember.

> I'm developing precision 
> agriculture software in which events happen on specific days (I use days 
> since yyyy-mm-dd), and in which some quantities may only be applicable 
> to a year, such as yield, or accumulated drainage.  For those I use 
> 'year', because the quantity is not associated with any one particular 
> day.  I can forsee some situation where two different persons get some 
> model output and their converted values are different because of the 
> average vs exact number of days per year issue.
> I understand that the Udunits folks might not want to tackle converting 
> our "strange" calendar's years or months to days.

Right.  That's outside the scope of the UDUNITS package, which was
designed to handle units of physical quantities only.

> Although now that I 
> think about it, doesn't everybody (at least in the Atmos Sci community) 
> have that same data table of number-of-days-per-month in at least one of 
> their programs?  Unless there is concern about code bloat in Udunits, 
> why not stick calendar conversions in there for commonly used calendars?
> Everyone would love to have it in there, I'm sure.

No doubt.  Unfortunately, it's non-trivial, would easily double the size
of the package, doesn't have any standards, and would consume time I
don't have.

What we need is a freely-available calendar package for C and Fortran.
If you know of one, then use it and let me know about it.

Steve Emmerson

NOTE: All email exchanges with Unidata User Support are recorded in the Unidata inquiry tracking system and then made publicly available through the web. If you do not want to have your interactions made available in this way, you must let us know in each email you send to us.