[hdf-forum] time data

[Ray Burkholder]

I use the boost::posix_time and boost::gregorian libraries for date/time
manipulation, and store the binary results in hdf5 files.

If you look at Boost::serialization, will serialize as text data, but no as
binary data.  There isn't much storage difference between the two formats,
but something about which to be aware.

Ray
 
> 
> To easily manipulate with dates/times (e.g. subtract from 
> each other) it is easiest to convert them to numbers. 
> Leapyears are always a bit nasty to handle.
> You have to have some reference date though (like Unix counts 
> from 1-Jan-1970).
> 
> An important question is the time span you think it will be used for.
> You could use an 8-byte floating point counting seconds from 
> 1-Jan-2020 on. This has an accuracy of 17 digits.
> So for a 20 year time span, you have 10 years of positive and 
> negative values. 10 years is 315360000 seconds, so you have 
> about 8 digits left for decimal seconds. Seems enough for 
> your case, but it's up to you.
> 
> For our astronomical work we use the ModifiedJulianDate as 
> 8-byte floating point. A class takes care of all arithmetic 
> and so involved with it.
> 
> Another option is to use two long integer values (for seconds 
> and nanoseconds), but the arithmetic will require a bit more work.
> 
> BTW Ho do you deal with Daylight Saving Time? Or do you 
> record all times in UTC?
> 
> 
> >>> Mag Gam <magawake at gmail.com> 06/17/09 3:17 AM >>>
> The resolution should be the same.
> 
> The accuracy should be very high...
> 
> For instance: 43.33245-43.33242
> 
> 12:33:43.33245 minus 12:33:43.33242 should equal .00003
> 
> Thanks again for the response...
> 
> 
> On Tue, Jun 16, 2009 at 8:22 AM, Ray 
> Burkholder<ray at oneunified.net> wrote:
> > what resolution/accuracy do you need?
> >
> >> -----Original Message-----
> >> From: Mag Gam [mailto:magawake at gmail.com]
> >> Sent: Tuesday, June 16, 2009 08:27
> >> To: hdf-forum at hdfgroup.org
> >> Subject: [hdf-forum] time data
> >>
> >> If I would like to store time series data in the x column, what is 
> >> the best data type to use?
> >>
> >> My data looks like this:
> >>
> >> 2009-10-10 12:33:43.33242
> >> 2009-10-10 12:33:43.33245
> >> 2009-10-10 12:33:43.63433
> >> 2009-10-10 12:33:43.73242
> >> 2009-10-10 12:33:43.83242
> >> 2009-10-10 12:33:43.93242
> >> 2009-10-10 12:33:43.99443
> >> 2009-10-10 12:33:44.43242
> >>
> >> Any thoughts?
> >>
> >> TIA
> >>
> >> 
> ---------------------------------------------------------------------
> >> - This mailing list is for HDF software users discussion.
> >> To subscribe to this list, send a message to hdf-forum- 
> >> subscribe at hdfgroup.org.
> >> To unsubscribe, send a message to 
> hdf-forum-unsubscribe at hdfgroup.org.
> >>
> >>
> >> --
> >> Scanned for viruses and dangerous content at 
> >> http://www.oneunified.net and is believed to be clean.
> >>
> >>
> >> No virus found in this incoming message.
> >> Checked by AVG - www.avg.com
> >> Version: 8.5.339 / Virus Database: 270.12.63/2169 - Release Date:
> >> 06/15/09 17:54:00
> >
> >
> > --
> > Scanned for viruses and dangerous content at 
> http://www.oneunified.net 
> > and is believed to be clean.
> >
> >
> 
> ----------------------------------------------------------------------
> This mailing list is for HDF software users discussion.
> To subscribe to this list, send a message to 
> hdf-forum-subscribe at hdfgroup.org.
> To unsubscribe, send a message to hdf-forum-unsubscribe at hdfgroup.org.
> 
> 
> 
> ----------------------------------------------------------------------
> This mailing list is for HDF software users discussion.
> To subscribe to this list, send a message to 
> hdf-forum-subscribe at hdfgroup.org.
> To unsubscribe, send a message to hdf-forum-unsubscribe at hdfgroup.org.
> 
> 
> --
> Scanned for viruses and dangerous content at 
> http://www.oneunified.net and is believed to be clean.
> 
> 


-- 
Scanned for viruses and dangerous content at 
http://www.oneunified.net and is believed to be clean.


----------------------------------------------------------------------
This mailing list is for HDF software users discussion.
To subscribe to this list, send a message to hdf-forum-subscribe at hdfgroup.org.
To unsubscribe, send a message to hdf-forum-unsubscribe at hdfgroup.org.