One very powerful feature in Context Broker GE is the ability to perform geo-located queries. You can query entities using the following spatial relationships:

  • georel=near: proximity to a geometry. It supports the following modifiers:
    • maxDistance: express, in meters, the maximum distance at which matching entities must be located.
    • minDistance: express, in meters, the minimum distance at which matching entities must be located.
  • georel=coveredBy: covered by a defined geometry.
  • georel=intersects: intersected with a reference gometry.
  • georel=equals: equality to a geometry.
  • georel=disjoint: not intersected with a geometry.

The header Fiware-Service: tourguide must be added to every request, so that the proper tenant is specified.

For example, to query for all the restaurants within 13 km of Vitoria-Gasteiz city center (identified by GPS coordinates 42.846718, -2.671635) a Context Consumer application will use the following query:

GET <cb_host>:<cb_port>/v2/entities?georel=near;maxDistance:13000&geometry=point&coords=42.846718,-2.671635

To query for all restaurants inside a defined zone inside Vitoria-Gasteiz city a Context Consumer application will use the following query:

GET <cb_host>:<cb_port>/v2/entities?georel=coveredBy&geometry=polygon&coords=42.847476,-2.763969;42.826006,-2.743151;42.826485,-2.653740;42.867061,-2.630934;42.881801,-2.640617;42.867767,-2.726723;42.847476,-2.763969