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Re: geo:lat owl:samePropertyAs vcard:latitude? (vCard/RDF)

From: Norman Gray <norman@astro.gla.ac.uk>
Date: Thu, 23 Nov 2006 22:34:20 +0000
Message-Id: <A6574B66-59BC-4830-9D43-C2C35E1EA7A6@astro.gla.ac.uk>
Cc: semantic-web@w3.org
To: Bernard Vatant <bernard.vatant@mondeca.com>

Hello Bernard,

On 2006 Nov 23 , at 19.00, Bernard Vatant wrote:

>> ...it would probably be more sensible to go in the other  
>> direction, and say
>>>  geo:lat     rdfs:subPropertyOf     vcard:latitude
> Why not the other way round? I would expect the geo: namespace to  
> define very generic properties, independent of any specific use and  
> any coordinates system.

I agree.

I simply meant that a position referring to WGS84 should be a  
subproperty of a more generic lat/long definition.  It would be  
sensible for that generic position to be defined in the geo:  
namespace (with a separate side-order of WGS84 if it were felt  
absolutely necessary), exactly as you suggest.

In fact, I think my suggestion is simpler than this.

My suggestion is this: I fear that the wgs84_pos namespace is  
misnamed.  It should instead be renamed simply 'pos', and references  
to WGS84 removed, on the grounds that many/most of the things thus  
marked up are not, in fact, WGS84 coordinates.

If you read coordinates off a GPS receiver then yes, they're probably  
WGS84.  But if you read coordinates off of Google maps, or any paper  
map or atlas, or a Galileo receiver which has dropped through a  
wormhole from 2010, or by doing your own surveying or interpolation,  
then they're very probably not (they're likely not far off, but  
they're not WGS84 coordinates to any greater extent than they're  
WGS72 or ITRS-like or Ordnance Survey coordinates).

If you want to be extra-precise and record the datum (not a bad idea,  
if you actually know it, and if your coordinates are sufficiently  
precise for it to make a difference), then add a 'datum' property to  
the the #SpatialThing.

Given that, then yes, it would be eminently reasonable to make the  
vCard: position equivalent to the geo: one.

...which is where I came in.

All the best,


Norman Gray  /  http://nxg.me.uk
eurovotech.org  /  University of Leicester, UK
Received on Thursday, 23 November 2006 22:35:18 UTC

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