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Reverse wikipedia geotagging lookup

Asked 2009-09-09T16:30:37.137
13

Wikipedia is geotagging a lot of its articles. (Look in the top right corner of the page.)

Is there any API for querying all geotagged pages within a specified radius of a geographical position?

Update

Okay, so based on lost-theory's answer I tried this (on DBpedia query explorer):

PREFIX geo: <http://www.w3.org/2003/01/geo/wgs84_pos#>
SELECT ?subject ?label ?lat ?long WHERE {
    ?subject geo:lat ?lat.
    ?subject geo:long ?long.
    ?subject rdfs:label ?label.
    FILTER(xsd:float(?lat) - 57.03185 <= 0.05 && 57.03185 - xsd:float(?lat) <= 0.05
        && xsd:float(?long) - 9.94513 <= 0.05 && 9.94513 - xsd:float(?long) <= 0.05
        && lang(?label) = "en"
    ).
} LIMIT 20

This is very close to what I want, except it returns results within a (local) square around the point and not a circle. Also I would like if the results where sorted based on the distance from the point. (If possible.)

Update 2

I am trying to determine the euclidean distance as an approximation of the true distance, But I am having trouble on squaring a number in SPARQL. (Question opened here.) When I g

geolocation sparql wikipedia geotagging
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2 Answers

3

The OpenLink Virtuoso server used by the dbpedia endpoint has several query features. I found the information on http://docs.openlinksw.com/virtuoso/rdfsparqlgeospat.html useful for a similar problem.

I ended up with a query such as this:

SELECT ?page ?lat ?long (bif:st_distance(?geo, bif:st_point(15.560278, 58.394167)))
WHERE{
    ?m foaf:page ?page.
    ?m geo:geometry ?geo.
    ?m geo:lat ?lat.
    ?m geo:long ?long.
    FILTER (bif:st_intersects (?geo, bif:st_point(15.560278, 58.394167), 30))
}
ORDER BY ASC 4 LIMIT 15

This example retrieves the geotagged locations within 30 km from the origin position.

answered 2011-07-01T15:03:21.830
1

Not an API, but you can also download this nice set of all geo-tagged wikipedia articles and query it directly in a local database: http://www.google.com/fusiontables/DataSource?dsrcid=423292

answered 2012-01-13T02:59:33.183

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