Thanks again, Seth, now it's clear. Cheers, Andreas.
> If your intervals are contiguous, time_bounds[i,1] should equal > time_bounds[i+1,0] (See the beginning of section 7.1 in the CF spec.) So for > January 2013, you should set the endpoint to 2013-02-01 00:00:00. > > (The resulting potential for confusion is why I think it's best practice to > put > the time coordinate at the midpoint of the interval rather than either end.) > > There's been some discussion of time resolution on this list, but nothing > that's made it into the spec. > > Cheers, > > --Seth > > > On Fri, 15 Mar 2013 23:12:27 +0100 > Andreas Hilboll <[email protected]> wrote: >> Seth, thanks for this nice walkthrough! I still have one question, >> regarding 3): >> >> for Jan 2013, I would chose 2013-01-01 00:00:00 as the start point, but >> what about the end point? >> >> - 2013-01-31 23:59:59 >> - 2013-01-31 00:00:00 >> - ... >> >> Is it possible to somehow set the time 'resolution' >> >> Cheers, Andreas. >> >> >>> 1) Set the time values to the midpoint of the time interval.* >>> >>> 2) Set a "cell_methods" attribute on the data variable with a >>> value of "time: mean (interval: 1 month)". >>> >>> 3) Create a time_bounds variable with dimensions (time,2) >>> whose values are the start and end points of each time interval. >>> >>> 4) Set a "bounds" attribute on the time coordinate variable >>> equal to the name of your time_bounds variable. >>> >>> *CF allows you to put the time coordinate anywhere in the >>> interval, but in my experience at the midpoint is the best option, >>> as it is the most intuitively obvious and least likely to cause >>> problems if you ever create aggregations over longer periods. >>> >>> Cheers, >>> >>> --Seth >>> >>> On Fri, 15 Mar 2013 22:45:39 +0100 >>> Andreas Hilboll <[email protected]> wrote: >>>> Hi, >>>> >>>> I want to store monthly averages of gridded satellite measurements of >>>> atmospheric trace gas columns. I'm wondering how I should specify the >>>> time axis, i.e. set the time for each monthly aggregate to the first, or >>>> the central, or the last day of the month. How should I specify that the >>>> values are actually monthly averages? >>>> >>>> Thanks for your ideas! >>>> Cheers, Andreas. >>>> _______________________________________________ >>>> CF-metadata mailing list >>>> [email protected] >>>> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >>> >> > _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
