Use Case ONTO23: Longest Line

[ar-chad]

Use Case ONTO23

Longest Line

As a GeoSPARQL data user I would like to retrieve the longest line corresponding to maximum distance between two geometries - distance between their farthest points.

Distance is measured in the units of the spatial reference system.

If geometries are the same, the function will return the line corresponding to the longest distance between the two farthest points in this geometry.

For the POINT(4 3 0) and the LINESTRING(0 0 0, 4 2 0) the value is LINESTRING (0 0 0, 4 3 0).

Function signature:

longestLine(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 longest line function is discoverable.

Postconditions

A SPARQL query can be executed that includes a function to return longest line from a given geometry to another given geometry - corresponding to the distance between their farthest points. The results of the query are known to be true or false in 2D and 3D.

Steps

Actor: discovers longest line function implemented by the system
Actor: executes a SPARQL query containing longest line function with two geometries as arguments.
System: returns a SPARQL result with a longest line between geometries - corresponding to distance between their farthest points.