- From: Norman Gray <norman@astro.gla.ac.uk>
- Date: Thu, 23 Nov 2006 22:34:20 +0000
- To: Bernard Vatant <bernard.vatant@mondeca.com>
- Cc: semantic-web@w3.org
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 -- ------------------------------------------------------------------------ ---- Norman Gray / http://nxg.me.uk eurovotech.org / University of Leicester, UK
Received on Thursday, 23 November 2006 22:35:18 UTC