Re: [CF-metadata] calendar-based units of time
Hi Jonathan: On 12/17/2012 10:51 AM, Jonathan Gregory wrote: Dear John I have prototyped similar functionality in the CDM, documented here: http://www.unidata.ucar.edu/software/netcdf-java/CDM/CalendarDateTime.html Thanks for this. I recall the earlier discussion and I think what you have implemented would be a good extension to CF, namely * Optional prefix "calendar" to the time-units means the corresponding component of time is manipulated. You show only years and months. Do you also accept the unproblematic units of days, hours, minutes and seconds with "calendar" prefixed? Do you allow the SI prefixes to these units? yes, the same periods are allowed that are in the udunits grammer: period = "millisec" | "msec" | "second" | "sec" | "s" | "minute" | "min" | "hour" | "hr" | "day" | "week" | "month" | "mon" | "year" | "yr" we do not allow SI prefixes. we do allow plural forms, ie with an appended s. * With calendar, only integer numbers of units are allowed. Are negative numbers allowed? yes * Invalid dates caused by adding months and years are decremented in whole days until a valid date is reached. yes regards, John ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
[CF-metadata] calendar-based units of time
Dear John > I have prototyped similar functionality in the CDM, documented here: > > http://www.unidata.ucar.edu/software/netcdf-java/CDM/CalendarDateTime.html Thanks for this. I recall the earlier discussion and I think what you have implemented would be a good extension to CF, namely * Optional prefix "calendar" to the time-units means the corresponding component of time is manipulated. You show only years and months. Do you also accept the unproblematic units of days, hours, minutes and seconds with "calendar" prefixed? Do you allow the SI prefixes to these units? * With calendar, only integer numbers of units are allowed. Are negative numbers allowed? * Invalid dates caused by adding months and years are decremented in whole days until a valid date is reached. Best wishes Jonathan ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
[CF-metadata] calendar-based units of time
On 12/14/2012 10:35 AM, Jonathan Gregory wrote: I think that calendar-based units of time cannot be introduced without a new syntax for time units, and some rules about how to interpret the cases when adding months to a reference date gives an impossible date. We could make such changes to the convention. I have prototyped similar functionality in the CDM, documented here: http://www.unidata.ucar.edu/software/netcdf-java/CDM/CalendarDateTime.html John ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
