Support GeoSPARQL functions

[1ec5]

Sophox currently provides the geof:distance function but none of the other GeoSPARQL functions. These functions would expand Sophox’s use cases to the point where it might begin to be a tool of choice for some OSM analysis needs. For example:

• geof:buffer would enable visualizing radii around features’ centroids in the map view.
• geof:within would make it possible to query for features whose centroids fall within a given nonrectangular, noncircular region.

Combined with access to full geometries (#16), these functions would enable a much wider range of use cases, for example:

• How long is U.S. Route 50?
• What is the largest building (by square footage or volume)?
• How many long-distance cycling routes travel through a given bounding box?
• How many miles of bike lanes are there in a given bounding box?
• What are the most common height restrictions for underpasses that go under railroads?
• Give me the fixmes inside national parks.

These use cases currently require the Overpass API, which can easily run into memory or runtime limits over large or dense enough areas.

This Phabricator ticket tracks enabling the same functions in the Wikidata Query Service.

[camelCaseNick]

geof:within would be especially helpful in conjunction with a limited to region property, in contrast to P48, directly linking to the boundary relations. (see Talk:Data items → Geographical regions as qualifiers)