The GeoTagger Processor can be used to enrich a GeoEvent with the name of an area of interest, also known as a geofence, with which the GeoEvent's geometry has a specified spatial relationship.
GeoTagging is a special case of event enrichment and spatial filtering. For example, you can configure a the GeoTagger Processor to append the names of any geofences a GeoEvent's geometry is found to be inside. GeoEvents processed by the GeoTagger Processor will have a field appended to it that contains the names of any geofences in which its geometry is found.
Nota:
Geofences must be imported into GeoEvent Server from a feature service prior to configuring a GeoTagger Processor. See Managing geofences to learn more about working with geofences in GeoEvent Server.
When configuring the GeoTagger Processor, you must select a spatial operator to specify the relationship that must be satisfied in order for the processor to tag a GeoEvent. For example, you might want to enrich GeoEvents by tagging them with the name of any geofence a GeoEvent's polygon intersects.
The GeoTagger Processor supports a range of spatial operators including Contains Any, Crosses Any, Disjoint Any, Enter Any, Equals Any, Exit Any, Inside Any, Intersects Any, Outside Any, Overlaps Any, Touches Any, and Within Any. These operators assume any geofence being considered, which satisfies the operator's defined spatial relationship, is sufficient to trigger the GeoTagger Processor to enrich the GeoEvent being processed.
For example, if the Intersects Any spatial operator is selected, and several dozen geofences modeling non-overlapping areas of interest are being considered, then the name of any geofence whose area intersects a GeoEvent's geometry would be added to that GeoEvent being processed.
Nota:
It is common to think of a geofence as modeling an area of interest, implying that geofences are always polygon geometries. A geofence could also be a point or polyline geometry, as the list of supported spatial operators implies. A polygon geometry associated with a GeoEvent could be tested to see if it intersects, crosses, or contains a geofence whose geometry is a point or polyline.
When specifying the name of the field containing a GeoEvent's geometry, GeoTagger will accept either the name of the event field or a tag (typically the GEOMETRY tag) that has been applied to a field in the GeoEvent Definition.
The GeoTagger Processor 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. Specify a name for the new resulting GeoEvent Definition as well as a name for the field the GeoTagger Processor will write its enriched values.
Three options are available for how the GeoTagger Processor will format its enriched values. Delimited Value specifies that geofence names should be written as a simple comma-separated list. The other two options format the enriched values as a JSON List or as elements in a JSON Group. Configuring the GeoTagger Processor to include the name of the geofence category in the enrichment and returning the United States and counties as separate categories of geofences, GeoTagging enrichment might take the following forms:
- List: ["UnitedStates/California","Counties/San_Bernardino"]
- Group: [{"Category":"UnitedStates","Name":"California"},{"Category":"Counties", "Name":"San_Bernardino"}]
For more information on the GeoTagger Processor, see the Introduction to GeoEvent Server tutorial available from GeoEvent Server tutorials.