Re: 20021223: time conventions

>To: <address@hidden>
>From: "Jeremy Cothran" <address@hidden>
>Subject: time conventions
>Organization: UCAR/Unidata
>Keywords: 200212211725.gBLHPHt21606

Hi Jeremy,

> I've been looking through the netCDF documentation trying to find if
> there is a standard, well-supported way of defining a delta
> time(delta_t) for netCDF files so that I don't have to articulate each
> regularly spaced time instance.  I have seen the attributes init_time
> and delta_t used in some of the header files, but when I try to use
> this with a utility like ncBrowse, it does not understand the
> convention.  I'd like to use my netCDF files with DODS servers and
> other netCDF utilities(NCO for instance), but I'm unsure which time
> conventions are generally supported and which are particular to a given
> user/group.

Unfortunately, there is no universal delta time convention for netCDF
that is supported by DODS servers and netCDF utilities.  The closest
thing there is to a standard way of representing time in netCDF files
is the use of the udunits conventions as described here:

  http://www.unidata.ucar.edu/staff/russ/netcdf/time/recs.html

There are also some links in the FAQ document under the question
"What is the best way to handle time using netCDF?":

  http://www.unidata.ucar.edu/staff/russ/netcdf/faq.html#time

But these don't really address the delta_t question, which is
discussed, but not settled, in the following postings:

  http://www.unidata.ucar.edu/staff/russ/netcdf/time/0031.html
  http://www.unidata.ucar.edu/staff/russ/netcdf/time/0032.html

--Russ

_____________________________________________________________________

Russ Rew                                         UCAR Unidata Program
address@hidden                     http://www.unidata.ucar.edu