The Union Creator Processor can be used to produce a geometric union of a GeoEvent's associated geometry with one or more geometries you have imported as geofences. The processor requires the GeoEvent field containing the geometry be specified. You can specify either the GeoEvent field name or a tag applied to a field within a GeoEvent Definition that identifies the geometry field.
The processor can be configured to either replace the GeoEvent's geometry with the union of the specified geometries or place the union into a new geometry field. Adding a new field to a GeoEvent alters the GeoEvent's schema, which requires GeoEvent Serverto create a new GeoEvent Definition. The new GeoEvent Definition will be managed by GeoEvent Server and deleted if changes are made to the processor or the GeoEvent Service in which the processor participates.
Unlike other processors, such as Difference, Symmetric Difference, and Intersector, which only operate with two discrete geometries, the Union Processor accepts a regular expression, allowing several different geofences to be specified. Consequently, you are able to obtain the union of a received GeoEvent's geometry with one or more geometries that have been imported as geofences.
For more information on the Union Creator Processor, see the Introduction to GeoEvent Server tutorial available from GeoEvent Server tutorials.