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 closest coordinate function is discoverable.
Postconditions
A SPARQL query can be executed that includes a function to return closest 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 closest coordinate function implemented by the system
Actor: executes a SPARQL query containing closest coordinate function with a point and geometry arguments.
System: returns a SPARQL result with a point that is a closest coordinate of a geometry to the given point.
Use Case ONTO16
Closest Coordinate
As a GeoSPARQL data user I would like to retrieve coordinate of a geometry closest to 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:
closestCoordinate(geometry: ogc:geomLiteral, geometry: ogc:geomLiteral): geometry: ogc:geomLiteralActor: 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 closest coordinate function is discoverable.
Postconditions
A SPARQL query can be executed that includes a function to return closest 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 closest coordinate function implemented by the system Actor: executes a SPARQL query containing closest coordinate function with a point and geometry arguments. System: returns a SPARQL result with a point that is a closest coordinate of a geometry to the given point.