|Bounding box containment||An index service which will allow efficient queries to be made identifying coordinate points that reside within a given bounding box. A more sophisticated version would understand types of entities.
‘Find me the postcodes in this area, or the wards in this area’, etc.
|Geometric queries||Queries involving one type of geometry (e.g. point) to another (e.g. polygon), nearest services, co-ordinate data points that lie within given polygon, intersection of two polygons, transect line.
“Which areas are contained within / touch / overlap with another given area?”
“Is this point within any other spatial area?”
“What is within this area of interest that I have defined?”
“Can I generalise a larger area from these smaller areas?”
|Free text search||RDF stores are generally bad at doing searches that have interesting things in them (partial matches, case, wildcards, etc.), certainly on large datasets.
This provides an auxiliary service, that indexes the store, and then enables pure text searches to be done over the external service.