Subject: RE: [Geopriv] coordinates

From: "Winterbottom, James" <[email-masked]>
Date: Wed, 16 Nov 2005 15:24:04 -0600

Hi Carl,

As Henning pointed out, and I think I got the gist of in my response is
that the reference point is likely to be arbitrary from application to
application, and so this probably need to be specified directly in the
document somehow and clearly discernable as being the reference
location. If a profile is defined for GML, isn't the profile itself
built-up with a reference in mind, so the profile would need to change
from one presence instantiation to the next, something that might be
nice to avoid.

Cheers
James

> -----Original Message-----
> From: [email-masked] [mailto:[email-masked]] On
Behalf
> Of Carl Reed OGC Account
> Sent: Thursday, 17 November 2005 8:18 AM
> To: Ron Shacham; [email-masked]
> Cc: [email-masked]
> Subject: Re: [Geopriv] coordinates
> 
> You could do this using the GML 3.1.1 option in PIDF-LO - would
require a
> profile/schema of GML.
> 
> Carl
> 
> ----- Original Message -----
> From: "Ron Shacham" <[email-masked]>
> To: <[email-masked]>
> Cc: <[email-masked]>
> Sent: Wednesday, November 16, 2005 1:35 PM
> Subject: [Geopriv] coordinates
> 
> 
> > Hello.
> >
> > We have found it useful in a tracking application at Columbia to
support
> > the notion of coordinates within a specific place, and represent
this in
> a
> > presence document.  For example, in an auditorium, we wish to keep
track
> > of a user's (X, Y, Z) coordinates, with respect to a corner that is
> chosen
> > as the point of reference. Although the pidf-lo format borrows an
> existing
> > format for representing civil location, might it nevertheless be
useful
> to
> > extend the format to include such a coordinate element?
> >
> > Regards,
> > Ron
> >
> > _______________________________________________
> > Geopriv mailing list
> > [email-masked]
> > https://www1.ietf.org/mailman/listinfo/geopriv
> 
> 
> _______________________________________________
> Geopriv mailing list
> [email-masked]
> https://www1.ietf.org/mailman/listinfo/geopriv

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---

From: Henning Schulzrinne <[email-masked]>
Date: Wed, 16 Nov 2005 16:31:03 -0500

While encoding the reference point would be nice, I'm less worried about 
that. In many cases, this information might well be known for the 
specific venue and just needs to be reproducible. I'd even be ok with 
simply defining the south-west (say) corner of such spaces as the 
arbitrary reference point if a universal understanding of that concept 
is helpful for interoperability. In more abstract terms, what I think 
would do the trick is a combined description that says:

(1) "X, Y distance (in meters) from a reference point at a particular 
civic address (room, lot)" or

(2) "X, Y distance (in meters) from a particular geo coordinate"

The latter is less important since one can convert this into geo 
coordinates, albeit with some practical difficulty.

We have an ultrawideband sensing device that can determine X, Y, Z 
coordinates in a largish space of several thousand square feet to 6 inch 
precision. Obviously, it reports this information as offsets, not long/lat.

Henning

---

From: "Carl Reed OGC Account" <[email-masked]>
Date: Wed, 16 Nov 2005 14:40:24 -0700

James -

I believe that you are correct, although I suspect some GML guru could 
figure out a way to fulfill the Columbia requirement while at the same time 
honoring the current structure and guidance contained in the PIDF-LO 
document :-)

Now in the case of a profile of GML and if I understand your assertion 
correctly. Consider my last posting  on the Simple Feature profile. The GML 
SF profile has its own xsd and I believe that the answer is No as long as 
the implementer abides by the rules of the profile and does not seek to 
extend the profile in any way. On the flip side, we also have many folks 
implementing application schemas for GML. In the case of applications 
schemas, you assertion is absolutely correct.

Regards

Carl

----- Original Message ----- 
From: "Winterbottom, James" <[email-masked]>
To: "Carl Reed OGC Account" <[email-masked]>; "Ron Shacham" 
<[email-masked]>; <[email-masked]>
Cc: <[email-masked]>
Sent: Wednesday, November 16, 2005 2:24 PM
Subject: RE: [Geopriv] coordinates