Description
Use Case ONTO18
Compactness Ratio
As a GeoSPARQL data user I would like to measure compactness ratio of a geometry.
In 2D the function returns the square root of the polygon’s area divided by the area of the circle with circumference equal to the polygon’s perimeter. In 3D the classical compactness of a solid can be measured by the ratio (area^3)/(volume^2), which is dimensionless and minimised by a sphere.
Function signature:
compactnessRatio(geometry: ogc:geomLiteral): : xsd:double
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 compactness ratio function is discoverable.
Postconditions
A SPARQL query can be executed that includes a function to return compactness ratio of a given geometry. The results of the query are known to be true or false in 2D and 3D.
Steps
Actor: discovers compactness ratio function implemented by the system
Actor: executes a SPARQL query compactness ratio function with a geometry argument.
System: returns a SPARQL result with a value that is a compactness ratio of a geometry.
Activity