Uniquely identified by lat/long/alt. i.e. spaciallyIntersects(P1, P2) :- lat(P1, LAT), long(P1, LONG), alt(P1, ALT), lat(P2, LAT), long(P2, LONG), alt(P2, ALT). sameThing(P1, P2) :- type(P1, Point), type(P2, Point), spaciallyIntersects(P1, P2). A point, typically described using a coordinate system relative to Earth, such as WGS84. point Anything with spatial extent, i.e. size, shape, or position. e.g. people, places, bowling balls, as well as abstract areas like cubes. SpatialThing A vocabulary for representing latitude, longitude and altitude information in the WGS84 geodetic reference datum. Version $Id: wgs84_pos.rdf,v 1.22 2009/04/20 15:00:30 timbl Exp $. See http://www.w3.org/2003/01/geo/ for more details. WGS84 Geo Positioning: an RDF vocabulary $Date: 2009/04/20 15:00:30 $ Recent changes to this namespace: $Log: wgs84_pos.rdf,v $ Revision 1.22 2009/04/20 15:00:30 timbl Remove the time bits which have been deal with elsewhere eg in iCal. Revision 1.21 2009/04/20 12:52:47 timbl try again Revision 1.20 2009/04/20 12:42:11 timbl Add Event (edited ages ago and never checked in), and location (following discussion http://chatlogs.planetrdf.com/swig/2009-04-20#T12-36-09) Revision 1.19 2009/04/20 12:36:31 timbl Add Event (edited ages ago and never checked in), and location (following discussion http://chatlogs.planetrdf.com/swig/2009-04-20#T12-36-09) Revision 1.18 2006/02/01 22:01:04 danbri Clarified that lat and long are decimal degrees, and that alt is decimal metres about local reference ellipsoid Revision 1.17 2004/02/06 17:38:12 danbri Fixed a bad commit screwup Revision 1.15 2003/04/19 11:24:08 danbri Fixed the typo even more. Revision 1.14 2003/04/19 11:16:56 danbri fixed a typo Revision 1.13 2003/02/19 22:27:27 connolly relaxed domain constraints on lat/long/alt from Point to SpatialThing Revision 1.12 2003/01/12 01:41:41 danbri Trying local copy of XSLT doc. Revision 1.11 2003/01/12 01:20:18 danbri added a link to morten's xslt rdfs viewer. Revision 1.10 2003/01/11 18:56:49 danbri Removed datatype range from lat and long properties, since they would have required each occurance of the property to mention the datatype. Revision 1.9 2003/01/11 11:41:31 danbri Another typo; repaired rdfs:Property to rdf:Property x4 Revision 1.8 2003/01/11 11:05:02 danbri Added an rdfs:range for each lat/long/alt property, http://www.w3.org/2001/XMLSchema#float Revision 1.7 2003/01/10 20:25:16 danbri Longer rdfs:comment for Point, trying to be Earth-centric and neutral about coordinate system(s) at the same time. Feedback welcomed. Revision 1.6 2003/01/10 20:18:30 danbri Added CVS log comments into the RDF/XML as an rdfs:comment property of the vocabulary. Note that this is not common practice (but seems both harmless and potentially useful). revision 1.5 date: 2003/01/10 20:14:31; author: danbri; state: Exp; lines: +16 -5 Updated schema: Added a dc:date, added url for more info. Changed the rdfs:label of the namespace from gp to geo. Added a class Point, set as the rdfs:domain of each property. Added XML comment on the lat_long property suggesting that we might not need it (based on #rdfig commentary from implementors). revision 1.4 date: 2003/01/10 20:01:07; author: danbri; state: Exp; lines: +6 -5 Fixed typo; several rdfs:about attributes are now rdf:about. Thanks to MortenF in #rdfig for catching this error. revision 1.3 date: 2003/01/10 11:59:03; author: danbri; state: Exp; lines: +4 -3 fixed buglet in vocab, added more wgs links revision 1.2 date: 2003/01/10 11:01:11; author: danbri; state: Exp; lines: +4 -4 Removed alt from the as-a-flat-string property, and switched from space separated to comma separated. revision 1.1 date: 2003/01/10 10:53:23; author: danbri; state: Exp; basic geo vocab geo latitude The WGS84 latitude of a SpatialThing (decimal degrees). The WGS84 longitude of a SpatialThing (decimal degrees). longitude The relation between something and the point, or other geometrical thing in space, where it is. For example, the realtionship between a radio tower and a Point with a given lat and long. Or a relationship between a park and its outline as a closed arc of points, or a road and its location as a arc (a sequence of points). Clearly in practice there will be limit to the accuracy of any such statement, but one would expect an accuracy appropriate for the size of the object and uses such as mapping . location lat/long A comma-separated representation of a latitude, longitude coordinate. The WGS84 altitude of a SpatialThing (decimal meters above the local reference ellipsoid). altitude