Re: A proposal for two additional properties for LOCN

Hi Frans,

> but frankly I did not really get Krzysztof's proposal to use guarded 
> restrictions to scope the CRS locally. Could someone (Krzysztof?) 
> elaborate on that?

I am sorry for the jargon. I was proposing to locally scope the 
relations on the level of the Geometry and CRS classes. This is often 
preferred to global domain and range restrictions. In our current draft, 
CRS is underspecified anyway, so we do not gain much by introducing the 
global range restriction anyway. However, we invite unintended 
consequences that may be more difficult to deal with later. One could 
easily construct such cases, e.g., by introducing a 'unknown' singleton 
for unspecified spatial, temporal, and semantic reference systems. 
Again, this is not a big deal in this particular case but asking the 
other way around what do we gain from the global range restriction?

Best,
Krzysztof

On 09/16/2014 03:25 AM, Frans Knibbe | Geodan wrote:
> Hello everyone,
>
> I took the liberty of updating the wiki page 
> <https://www.w3.org/community/locadd/wiki/Proposal_for_extension_of_LOCN_with_properties_for_Coordinate_Reference_System_and_Level_of_Detail>, 
> an attempt to keep the wiki up with the discussion. I have added a CRS 
> class. I sense agreement that introducing the CRS class is a step in 
> the right direction, but frankly I did not really get Krzysztof's 
> proposal to use guarded restrictions to scope the CRS locally. Could 
> someone (Krzysztof?) elaborate on that?
>
> As for the spatial resolution, I am struggling to find a good way to 
> express this. It seems to me we want to be able to specify a unit and 
> a value for the spatial resolution. I think it would be nice if we 
> could also define the spatial resolution to be a distance:  a regular 
> distance (measured in metres, feet, ....) or an angular distance 
> (measured in degrees, radians,...).  I took a brief look at QUDT 
> (http://qudt.org/), but I have not been able to find an appropriate 
> distance quantity. So suggestions are very welcome!
>
> Regards,
> Frans
>
>
>
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> Frans Knibbe
> Geodan
> President Kennedylaan 1
> 1079 MB Amsterdam (NL)
>
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> E frans.knibbe@geodan.nl
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-- 
Krzysztof Janowicz

Geography Department, University of California, Santa Barbara
4830 Ellison Hall, Santa Barbara, CA 93106-4060

Email: jano@geog.ucsb.edu
Webpage: http://geog.ucsb.edu/~jano/
Semantic Web Journal: http://www.semantic-web-journal.net