DF> Tools could generate 4D locations as needed from 3+1D.
In practice, it is not straight-forward to do it the other way around -
though (of course) it can be done. That is assuming that it is clear from
the context whether an altitude and/or time is assumed. E.g. in Berlin's
case, there is some kind of geoid-level altitude assumed. (01)
> -----Original Message-----
> From: ontolog-forum-bounces@xxxxxxxxxxxxxxxx [mailto:ontolog-forum-
> bounces@xxxxxxxxxxxxxxxx] On Behalf Of doug foxvog
> Sent: 27 October 2010 05:40
> To: [ontolog-forum]
> Cc: ontolog-forum@xxxxxxxxxxxxxxxx
> Subject: Re: [ontolog-forum] GPS coordinates in an ontology?
>
> On Tue, October 26, 2010 14:49, sean barker said:
> > Just to add to the problem, it is interesting to compare the position
> > of Berlin according to various sources:
>
> Berlin is almost 900 sq. km. Giving its position to centi-microns, as
> Geonames does makes no sense. If there is a an official marker from which
> distances are measured, it makes some sense to give its location to the
> closest meter. Specifying its center to the decimeter is not very useful.
>
> An ontology for representing static places that extend in area needs more
> than just to specify a single point. There are different ways to do this.
>
> Useful concepts to include in an ontology are
> * defined reference location
> * boundary curve(s) as one or more sets of vertexes with straight lines
> (or arcs) connecting them
> * bounding and bounded Mercator rectangle
> * bounding/bounded circle
> * Elevation
> + average
> + max & min
> * Error bars for all locations (a useful concept for all measured values).
>
> Just like other measured values, the ontology should have multiple units
> (and in this case systems of units) in which positions can be expressed.
> Conversion tools or services should allow a value to be input/output using
> any appropriate desired system.
>
> Moving objects would have a relation that specifies their 2D or 3D
location
> at given times. Tools could generate 4D locations as needed from 3+1D.
>
> == doug foxvog
>
>
> > Geonames
> > 52.5243681651343;13.410530090332
> > Displayed as N52 31'27", E13 24'37", and 52.52437 13.41053
> > http://sws.geonames.org/2950159/
> >
> >
> > New York Times 52.6166667, 13.4 as geo: lat, long
> > http://data.nytimes.com/N50987186835223032381
> >
> >
> > DBpedia - 52.500557, 13.398889 as geo:lat long
> > AND 52 30' 2" 13 23' 56" as dbpprop:latd, latm, lats, longd, longm,
> > longs
> >
> > http://dbpedia.org/resource/Berlin
> >
> > Freebase 52.52334 13.41269, contained by Germany, Europe
> > http://rdf.freebase.com/ns/guid.9202a8c04000641f80000000000094d6
> >
> > The positions agree within about 1 km in longitude, but in longitude
> > the variation is of the order of 10 km.
> >
> > Sean Barker
> > Bristol, UK
> >
> >
> >> -----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?
> >>
> >>
> >> *** WARNING ***
> >>
> >> This message has originated outside your organisation, either from
> >> an external partner or the Global Internet.
> >> Keep this in mind if you answer this message.
> >>
> >>
> >> 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
> >
> >
> >
> >
> ________________________________________________________________
> _
> > Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
> > Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
> > Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
> > Shared Files: http://ontolog.cim3.net/file/ Community Wiki:
> > http://ontolog.cim3.net/wiki/ To join:
> > http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J
> > To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx
> >
> >
>
>
> =============================================================
> doug foxvog doug@xxxxxxxxxx http://ProgressiveAustin.org
>
> "I speak as an American to the leaders of my own nation. The great
initiative
> in this war is ours. The initiative to stop it must be ours."
> - Dr. Martin Luther King Jr.
> =============================================================
>
>
> ________________________________________________________________
> _
> Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
> Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
> Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
> Shared Files: http://ontolog.cim3.net/file/ Community Wiki:
> http://ontolog.cim3.net/wiki/ To join: http://ontolog.cim3.net/cgi-
> bin/wiki.pl?WikiHomePage#nid1J
> To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx
> (02)
_________________________________________________________________
Message Archives: http://ontolog.cim3.net/forum/ontolog-forum/
Config Subscr: http://ontolog.cim3.net/mailman/listinfo/ontolog-forum/
Unsubscribe: mailto:ontolog-forum-leave@xxxxxxxxxxxxxxxx
Shared Files: http://ontolog.cim3.net/file/
Community Wiki: http://ontolog.cim3.net/wiki/
To join: http://ontolog.cim3.net/cgi-bin/wiki.pl?WikiHomePage#nid1J
To Post: mailto:ontolog-forum@xxxxxxxxxxxxxxxx (03)
|