Event data frequently expresses coordinate values in geographic space using latitude and longitude. The Projector Processor can be used to project a GeoEvent's geometry from its native coordinate system to another spatial reference. For example, you might want to explicitly project event data in order to review its coordinate values in the context of a particular coordinate system.
It is recommended you understand the native coordinate system of the streaming data and how it relates to other spatial data you might have imported such as geofences. ArcGIS Server and GeoEvent Server typically project geometries as needed so spatial evaluations are conducted in a common spatial reference. ArcGIS Server will project data it receives to match a feature service's spatial reference, for example, before creating or updating features. GeoEvent Server will project spatial data on-the-fly before evaluating the data for intersection with a geofence.
Use this processor when you want to explicitly project the GeoEvent's before additional filtering or processing steps occur in a GeoEvent Service.
The processor requires that a 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 also requires the Well Known Identifier (WKID) of the coordinate system to which the input data will be projected. The WKID for the WGS 1984 World Geographic coordinate system, for example, is 4326.
For more information on supported coordinate systems, see Using spatial references.
The Projector Processor can be configured to replace the GeoEvent's geometry with the projected geometry or place the projected 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 Projector Processor, see the Introduction to GeoEvent Server tutorial available from GeoEvent Server tutorials.