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[UDUNITS #CVV-877033]: UDUNITS2 and utCalendar

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  • Subject: [UDUNITS #CVV-877033]: UDUNITS2 and utCalendar
  • Date: Mon, 04 Jan 2010 08:43:22 -0700
Rosalyn,

> The units of a netcdf(CF) time variable must contain a reference time.
> 
> E.g units = "days since 1970-01-01 00:00:00"      [ Valid time units and
> reference time]
> utScan told me this was a valid unit and I used utCalendar to convert it
> into a UTC-referenced time.  If conversion is successful it tells me the
> reference time was ok.
> 
> E.g units="days"  [Valid time units, but invalid/no reference time]
> utScan validates the time unit, but since there is no reference time,
> utCalendar fails indicating invalid/no reference time.
> 
> So I'm hoping there is another way to do this in UDUNITS2?

Piece of cake.  Just test if the "unit" in question is convertible with a known 
timestamp "unit".  For example:

#include <udunits2.h>
...
ut_system* system = ut_read_xml(NULL);
ut_unit*   secsSinceEpoch = ut_parse(system, "seconds since 1970-01-01", 
UT_ASCII);
...
ut_unit*   testUnit = ...;
if (!ut_are_convertible(secsSinceEpoch, testUnit)) {
    /* "testUnit" isn't a timestamp-unit */
}
else {
...
}

And Happy New Year!

> Thanks.
> 
> Regards,
> Rosalyn.
> ------------------------------------------------------------------------
> Rosalyn Hatcher
> NCAS Computational Modelling Services
> Dept. of Meteorology, University of Reading,
> Earley Gate, Reading. RG6 6BB
> Email: address@hidden     Tel: +44 (0) 118 378 6016

Regards,
Steve Emmerson

Ticket Details
===================
Ticket ID: CVV-877033
Department: Support UDUNITS
Priority: Normal
Status: Closed