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Re: Specifying units of the RDF geo:alt property

From: Charles McCathieNevile <chaals@opera.com>
Date: Wed, 02 Nov 2005 11:47:28 +0100
To: "Kjetil Kjernsmo" <kjetil@kjernsmo.net>, geowanking@lists.burri.to
Cc: semantic-web@w3.org
Message-ID: <op.szlz9exxwxe0ny@widsith.local>

Hi Kjetil,

On Tue, 01 Nov 2005 23:54:44 +0100, Kjetil Kjernsmo <kjetil@kjernsmo.net>  
wrote:

> Currently, it is undefined what it is...
>
> In a recent chat on #swig on irc.freenode.net, Dan Brickley suggested I
> should take the issue to these list, and he would implement any
> consensus that is formed here.
...
> I would personally tend to favour that the geo:alt property is specified
> as "The altitude above the local WGS 84 ellipsoid in meters", but
> clearly, this is problematic if there is allready a lot of data in the
> wild where it is given in e.g. feet. Then, I guess, the only hope is to
> use rdf:value, as seen in the example

I'd like to see people using datatypes to do this. In the SWAD-E geoInfo  
workshop in Budapest we came up with a couple of simple approaches to  
describing what floor of a building you are on [1] - something that is  
available to many people who don't have a GPS and rely on looking up their  
wgs84 points on some map. (I have no idea what the altitude of my office  
is in any unit except floors).

I know that implementors get upset if there are tags required that are  
long, but it is not actually terribly complex to use a datatype, except  
that with no clear mechanism for defining them in a machine-readable way  
you currently rely on some magic mechanism for dealing with them.

cheers

chaals

[1] http://www.w3.org/2001/sw/Europe/200409/geox/hi.rdf

-- 
Charles McCathieNevile                     chaals@opera.com
   hablo español  -  je parle français  -  jeg lærer norsk
      Peek into the kitchen: http://snapshot.opera.com/
Received on Wednesday, 2 November 2005 10:47:59 UTC

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