Subject: [Geopriv] Geolocation Policy and timezone

From: "Tschofenig, Hannes (NSN - FI/Espoo)" <[email-masked]>
Date: Tue, 22 Jul 2008 13:13:39 +0300

Recently we had a discussion on the list regarding expressing timezone
information in PIDF-LO. In context of that discussion I checked the
geolocation policy document and I noticed that we do not have a feature
related to timezones either. The only thing we have at the moment is the
ability to control the distribution of the time-offset (from RFC 5025).

Hence, there is no condition element that allows timezones to be used. 

Should we move forward with the document without adding a timezone
condition element? 

_______________________________________________
Geopriv mailing list
[email-masked]
https://www.ietf.org/mailman/listinfo/geopriv

---

From: [email-masked]
Date: Tue, 22 Jul 2008 12:45:40 -0400 (EDT)

Just thinking "out loud".

The location payload (geodetic) contained in an LO is the result of some
measurement process. From the OGC Observations and Measurements standard
(now also in the ISO process):

An observation is an act associated with a discrete time instant or period
through which a number, term or other symbol is assigned to a phenomenon.
The phenomenon is a property of an identifiable object, which is the
feature of interest of the observation. The observation uses a procedure,
which is often an instrument or sensor but may be a process chain, human
observer, an algorithm, a computation or simulator. The key idea is that
the observation result is an estimate of the value of some property of the
feature of interest, and the other observation properties provide context
or metadata to support evaluation, interpretation and use of the result.

The reason for providing the above process is that the time properties of
the observation are just as important as the location of the observation
for many applications. There may also be legal implications associated
with not having some time metadata associated with the LO observation. Of
course, the discussion gets interesting when one considers that there are
multiple time aspects associated with the collection of any observation -
sample time, result time, and so on.

The short of the long is that I would suggest that there be some time
metadata associated with an LO. FYI, the OGC uses the following ISO
document as the basis for defining time (as a profile of the ISO
document).

ISO 8601:2004, Data elements and interchange formats — Information
interchange Representation of dates and times.

Regards

Carl

---

From: "Brian Rosen" <[email-masked]>
Date: Tue, 22 Jul 2008 13:08:15 -0400

I note that the original posting was about communicating the time zone of
the location, which is a relatively unchanging piece of metadata directly
associated with the location, rather than a time stamp of a measurement.  A
timestamp may or may not have a timezone, but you wouldn't use the timestamp
of a measurement to determine the timezone of the location.

Brian

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On Behalf
> Of [email-masked]
> Sent: Tuesday, July 22, 2008 12:46 PM
> To: Tschofenig, Hannes (NSN - FI/Espoo)
> Cc: [email-masked]
> Subject: Re: [Geopriv] Geolocation Policy and timezone
> 
> ISO 8601:2004, Data elements and interchange formats - Information