Re: person location WRT position

Hi all, 
I'm new here. I'm getting involved in your activity because I'm managing a 
R&D European Project on Crisis Management (www.workpad-project.eu) where 
IBM Italia participates.

Also, here at my center we do some work with formal ontologies and 
cooperate with people at Laboratory of Applied Ontology at CNR Italy 
(www.loa-cnr.it)

As for this discussion, I'd suggest looking at how the problem has been 
addressed in well-known upper ontologies such as SUMO or DOLCE - the 
latter is my favourite one, have a look at 
http://www.loa-cnr.it/DOLCE.html 

In brief, according with these models, there is a distinction between 
Space Region which is abstract - like numbers - and denotes a region on 
the Earth (or possibly elsewhere) and, for concrete objects, the notion of 
Spatial Location which is the Quality of being placed in a Space Region at 
a certain time. Space regions are the same, whether are taken by stable 
objects or mobile things, while locations of objects change, often, 
seldom, maybe never. To allign with known upper ontologies, 'Position' 
could be a Spatial Location (i.e. a (reified) Quality, or a property if 
you whish), while 'Location' could be a class representing a Space Region 
in any suitable standard way.

Hope that help.

Cordiali Saluti, Best Regards,

Guido Vetere
Manager & Research Coordinator, IBM Center for Advanced Studies Rome
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IBM Italia S.p.A.
via Sciangai 53, 00144 Rome, 
Italy
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mail:     gvetere@it.ibm.com
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mobile: +39 335 7454658
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http://guidovetere.nova100.ilsole24ore.com/




Gavin Treadgold <gt@kestrel.co.nz> 
Sent by: public-xg-eiif-request@w3.org
17/09/2008 05.27

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Subject
Re: person location WRT position







On 2008-09-17, at 1502, Nuwan Waidyanatha wrote:

> IMO, location is relatively static because earth does rotate; relative
> to the sun; therefore, the address, if labeled as a location, is in
> motion.

No it isn't, as most of the co-ordinate systems used for location are 
fixed to the earth's frame of reference - this includes the underlying 
model (e.g. a global geoid that approximates the chape of the earth, 
or a regional grid that approximates a country or jurisdiction. These 
are usually either global co-ordinate systems or local - e.g. 
jurisdictions, regions or countries. The application of them depends 
on the accuracy required and the application of the data e.g. 
cadestral databases generally require a high degree of precision and 
are more prone to say shifting of tectonic plates over time.

In summary, most of the systems we use, such as WGS84 & Lat/Long move 
with the Earth's rotation so it is not an issue.

Cheers Gav




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