Actor: GeoSPARQL data user (human or software agent querying RDF dataset with GeoSPARQL)
Preconditions
Features and Geometries with 3D representations are present in a dataset to be queried. The triangle aspect function is discoverable.
Postconditions
A SPARQL query can be executed that includes a function to return triangle aspect of a given geometry or no value if the geometry is not a triangle. The results of the query are known to be true or false in 3D or 2D.
Steps
Actor: discovers triangle aspect function implemented by the system
Actor: executes a SPARQL query containing triangle aspect function with a geometry argument.
System: returns a SPARQL result with triangle aspect value of a given geometry or no value if the geometry is not a triangle.
Use Case ONTO12
Triangle Aspect
As a GeoSPARQL data user I would like to retrieve slope direction of a triangle - its aspect value in degrees.
Examples: aspect represents the main slope direction angle compared to the north direction. It can be thought of as the slope direction.
For the 'POLYGON((0 0 0, 3 0 0, 0 3 0, 0 0 0))' the value is 0.0. For the 'POLYGON((0 0 1, 3 0 0, 0 3 1, 0 0 1))' the value is 90.0.
Function signature:
triangleAspect(geometry: ogc:geomLiteral): xsd:doubleActor: GeoSPARQL data user (human or software agent querying RDF dataset with GeoSPARQL)
Preconditions
Features and Geometries with 3D representations are present in a dataset to be queried. The triangle aspect function is discoverable.
Postconditions
A SPARQL query can be executed that includes a function to return triangle aspect of a given geometry or no value if the geometry is not a triangle. The results of the query are known to be true or false in 3D or 2D.
Steps
Actor: discovers triangle aspect function implemented by the system Actor: executes a SPARQL query containing triangle aspect function with a geometry argument. System: returns a SPARQL result with triangle aspect value of a given geometry or no value if the geometry is not a triangle.