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

From: Bernard Vatant <bernard.vatant@mondeca.com>
Date: Fri, 24 Nov 2006 09:44:32 +0100
Message-ID: <4566B0F0.8010503@mondeca.com>
To: Norman Gray <norman@astro.gla.ac.uk>
Cc: semantic-web@w3.org

Hello Norman

>>>>  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.
> ...it would probably be more sensible to go in the other direction, 
> and say
>
> 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.
OK so we have 100% agreement on that. Great.
> 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.
Sure enough. And many people using this namespace have certainly not the 
faintest idea of what WGS84 is all about, maybe they are barely aware 
there are such concepts as different coordinates systems, projections 
etc. but they would certainly not be able to explain why this one, that 
one, and the differences.

Actually this use case should help us to set up best practices for any 
similar situation where you have to deal with numerical properties 
likely to come out of different measurement systems, hence with 
different values at a level of precision needed for technical 
applications, such differences being irrelevant in less technical 
contexts. Many examples come to mind when you think about it. I guess we 
have many such examples in astronomy - positions of stars, elements of 
orbits, whatever. For positions of stars, whatever catalogue is good for 
the backyard astronomer, whereas the professional use would certainly 
want to distinguish Hipparcos data from Gaia's when they are available. [1]

Bernard

[1] For people not familiar with this stuff :
http://en.wikipedia.org/wiki/Hipparcos_Catalogue
http://en.wikipedia.org/wiki/Gaia_probe

-- 

*Bernard Vatant
*Knowledge Engineering
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Received on Friday, 24 November 2006 08:44:43 GMT

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