Thanks for this implementation! If we implement such distance calculation in a
search engine, and sort the
result according to distance, this would be local search (search within a special region). In this case the
search vector has two dimensions (GPS coordinates). This is a special case of general similarity search
http://www.orthuber.com/wpa.htm
In general similarity search the search result is ordered according to a distance functions which can be
defined by all http URI owners (using the convention shown in Figure 2 of
http://www.orthuber.com/wp1.pdf ).
It would be possible to search generally for objects which have similar quantitative (numeric) description. So
the general application would be very attractive.
Wolfgang
----- Original Message -----
From: "Toby A Inkster" <[email protected]>
To: "Linked Data community" <[email protected]>
Sent: Sunday, June 21, 2009 10:45 AM
Subject: URIs for great circle arcs
Great circle arcs are the shortest surface paths between two points on a
spherical body. I've minted some
URIs (and am serving up RDF/ XML) for great circle arcs on the surface of the
Earth. Amongst other things,
the RDF/XML returned will tell you the distance between the points, the
compass bearing and the midpoint.
For example, the arc between London and Tokyo is represented as:
<http://ontologi.es/place/arc/51.507778;-0.128056/35.683333;139.766667>
which is a geo:SpatialThing. There is also:
<http://ontologi.es/place/arc/ 51.507778;-0.128056/35.683333;139.766667#points>
which is an rdfs:Container representing the (infinite) set of all points
between the two endpoints of the
line.
An additional feature is the ability to link to URIs representing the
endpoints. e.g.:
<http://ontologi.es/place/arc/
51.507778;-0.128056/35.683333;139.766667?uri1=http://dbpedia.org/
resource/London&uri2=http://dbpedia.org/resource/Tokyo>
The document you get returned still has a primaryTopic of
<http://ontologi.es/place/arc/51.507778;-0.128056/35.683333;139.766667>
(i.e. it doesn't alter the linked data URI) but now contains explicit dbpedia
references for the end
points. Those URIs don't have to be from dbpedia - they could be anything -
they're not used in
calculations of distances, etc - just included in the output.
Possible uses: flight and travel linked data.
Any ideas for improvements?
--
Toby A Inkster
<mailto:[email protected]>
<http://tobyinkster.co.uk>
