Subject: [VCARDDAV] GEO property

From: Renato Iannella <[email-masked]>
Date: Wed, 9 Dec 2009 00:29:12 +1000

Section B.9 of [1] says: "Made explicit that coordinates in the GEO property are expressed in the WGS 84 reference system" - but I can't see this in the normative text?

Also - other (popular) GEO vocabularies [2, 3, 4] usually split the property into separate "lat" and "long" properties.
Should we consider this?
 
Cheers...  Renato Iannella
NICTA

[1] http://tools.ietf.org/html/draft-ietf-vcarddav-vcardrev-09
[2] http://www.w3.org/2003/01/geo/
[3] http://microformats.org/wiki/geo
[4] http://microformats.org/wiki/hcard

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From: Simon Perreault <[email-masked]>
Date: Tue, 08 Dec 2009 10:06:12 -0500

> Section B.9 of [1] says: "Made explicit that coordinates in the GEO property are expressed in the WGS 84 reference system" - but I can't see this in the normative text?

Yes but B.3, which came later, says:

   o  Made GEO a URI.

Since then vCard is completely unconcerned with the URI syntax. It is up to the
URI scheme to define such things.

This is well specified in the "geo" URI scheme [draft-ietf-geopriv-geo-uri].

> Also - other (popular) GEO vocabularies [2, 3, 4] usually split the property into separate "lat" and "long" properties.

I think it is up to the "geo" URI people to decide whether they want to allow that.

Thanks,
Simon
-- 
DNS64 open-source   --> http://ecdysis.viagenie.ca
STUN/TURN server    --> http://numb.viagenie.ca
vCard 4.0           --> http://www.vcarddav.org

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From: "Alexander Mayrhofer" <[email-masked]>
Date: Tue, 22 Dec 2009 17:18:15 +0100

Hello,

As one of the authors of the "geo" URI, i'm very happy to see it
included in vcarddav. We've made very good progress on the URI scheme,
and it's going to IESG review hopefully pretty soon (so it should be an
RFC in Q1 or Q2 2010 ).

> > Section B.9 of [1] says: "Made explicit that coordinates in 
> the GEO property are expressed in the WGS 84 reference 
> system" - but I can't see this in the normative text?

The *default* CRS of the "geo" URI is WGS-84. The URI scheme allows the
use of other CRSes, given that they are registered with IANA (there will
be a "geo" URI CRS registry).

I would suggest to remove that text, or, rather, that "instances of the
'geo' URI in the default CRS of WGS-84 are preferred", if you want to
limit it specifically.

We've talked a *lot* in GEOPRIV about the choice of the default WGS, and
also have invested lots of time of investigating what the impacts are. I
do *strongly* suggest you to re-use that effort that has gone into the
"geo" URI, and not re-open the CRS discussion for vcarddav.
 
> URI scheme to define such things.

Right, and i can assure you it will save you a massive amount of time.
Note that this also provides you with a well-defined syntax to express
uncertainty in the location.
 
> > Also - other (popular) GEO vocabularies [2, 3, 4] usually 
> split the property into separate "lat" and "long" properties.
> > Should we consider this?
> 

That issue never came up during the discussion about the "geo" URI.
Seperating them would *only* make sense if there were use cases where an
isolated component would make sense. I cannot think of such a use case
for a spatial location, since "lat" and "long" always occur together -
both are required to properly specify the location.

Alex