Just to add to the problem, it is interesting to compare the position of
Berlin according to various sources: (01)
Geonames
52.5243681651343;13.410530090332
Displayed as N52 31'27", E13 24'37", and 52.52437 13.41053
http://sws.geonames.org/2950159/ (02)
New York Times 52.6166667, 13.4 as geo: lat, long
http://data.nytimes.com/N50987186835223032381 (03)
DBpedia - 52.500557, 13.398889 as geo:lat long
AND 52 30' 2" 13 23' 56" as dbpprop:latd, latm, lats, longd, longm,
longs (04)
http://dbpedia.org/resource/Berlin (05)
Freebase 52.52334 13.41269, contained by Germany, Europe
http://rdf.freebase.com/ns/guid.9202a8c04000641f80000000000094d6 (06)
The positions agree within about 1 km in longitude, but in longitude the
variation is of the order of 10 km. (07)
Sean Barker
Bristol, UK (08)
> -----Original Message-----
> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx
> [mailto:ontolog-forum-bounces@xxxxxxxxxxxxxxxx] On Behalf Of Chris
> Partridge
> Sent: 26 October 2010 12:46
> To: '[ontolog-forum] '
> Subject: Re: [ontolog-forum] Fw: GPS coordinates in an ontology?
>
>
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>
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>
>
> Hi,
>
> Ian mentions below I had done some work in this area.
>
> As Sean said earlier, it is useful to distinguish between the object
> being represented and its representation.
> As Ian points out below, it can take some effort to be sure what object
> is being presented.
>
> The team found that it is often geo-spatial (all three dimensions) and
> temporal data - rather than just spatial data that is of interested (at
> least in the defence domain we were working in). We are often interested
> in the things that stay in the same place (place? See Aristotle for more
> details) over time.
> Maybe because we have a 4D bias :-) we found a 4D approach useful.
> I give some pointers to the 4D approach below.
> A geo-spatial (all three dimensions) and temporal position (point) is a
> point in 4D.
> So (as Ian says below) if we were not interested in the temporal
> co-ordinate
> - in programming terms, it was stripped out - then we have a point in 3D
> (with an associated time) and a line in 4D.
> If (as Ian says below) we were not interested in the altitude
> co-ordinate - in programming terms, it was stripped out - then we have a
> line in 3D (with an associated time) and 4D.
> There were the standard issues about whether the line was the tangent to
> the normal of some reference ellipsoid or through some notional centre
> of the earth.
> If we were not interested in either the altitude or temporal
> co-ordinates, then we have a line in 3D and a plane in 4D.
>
> Interestingly we found that taking the 4D approach revealed some
> potential improvements in airspace management.
> We were interested and amused to find the term 4DATM (4D Air Traffic
> Management) is in use - whereas from our perspective this follows the
> traditional 3D + 1 approach (i.e. it is not 4D in our sense of the
> word).
> Our take on this was that this recognised the importance of looking at
> space and time together (for things like ATM) but did not make the
> (paradigm?) shift from 3D + 1 to 4D.
>
> Regards,
> Chris
>
snip (09)
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