Use Case ONTO20: Farthest Coordinate

[ar-chad]

Use Case ONTO20

Farthest Coordinate

As a GeoSPARQL data user I would like to retrieve coordinate of a geometry farthest from a given point.

For the 'POINT(0 0 0)' and the 'POLYGON((2 2 0, 10 0 0, 10 5 0, 0 5 0, 2 2 0) the value is POINT('2 2 0').

Function signature:

farthestCoordinate(geometry: ogc:geomLiteral, geometry: ogc:geomLiteral): geometry: ogc:geomLiteral

Actor: GeoSPARQL data user (human or software agent querying RDF dataset with GeoSPARQL)

Preconditions

Features and Geometries with 2D and 3D representations are present in a dataset to be queried. The farthest coordinate function is discoverable.

Postconditions

A SPARQL query can be executed that includes a function to return farthest coordinate of a given geometry to a given point. The results of the query are known to be true or false in 2D and 3D.

Steps

Actor: discovers farthest coordinate function implemented by the system
Actor: executes a SPARQL query containing farthest coordinate function with a point and geometry arguments.
System: returns a SPARQL result with a point that is a farthest coordinate of a geometry from the given point.