The Intersector Processor can be used to generate a geometry representing the intersection between a geofence and a GeoEvent's geometry. The GeoEvent geometry is considered the base—the geofence is the geometry being evaluated to determine if an intersection exists.
The intersection between two geometries is generally equal to or less than the geometric dimension of the geometries being considered. For example, if a GeoEvent's associated geometry is a point, even if the specified geofences geometry is a polyline or polygon, the intersection (assuming one exists) must be a point. If a GeoEvent's associated geometry is a polyline and the specified geofences geometry is a polygon, the intersection is most likely a line but could also be a point.
The processor requires two discrete geometries be specified. You will not, for example, be able to use a regular expression to specify several different geofences and obtain the intersection of each geofence with the geometry associated with the GeoEvent being processed.
The processor can be configured to either replace the GeoEvent's geometry with the discovered intersection or write the intersecting geometry into a new field. Adding a new field to a GeoEvent alters the GeoEvent's schema, which requires GeoEvent Server to 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.
For more information on the Intersector Processor, see the Introduction to GeoEvent Server tutorial available from GeoEvent Server tutorials.