Hello Sam -
No, I don't think so ... but I'm not as familiar with DEM as I am with simple feature classes.
GeoEvent Server offers two ways to enrich event records received in real-time:
1) GeoTagger - This is essentially spatial enrichment
2) Field Enricher - Essentially an attribute enrichment
Having established a feature set, you can import the feature geometries as geofences. You can then use a GeoTagger to determine if the Geometry associated with an event shares a spatial relationship with one or more geofences (e.g. intersects, within, crosses, disjoint ...)
Event enrichment using a GeoTagger is limited to enriching the event record with the name of the geofence with which it shares the specified spatial relationship. If you wanted to enrich the event record further, for example, to bring other attributes from the feature record whose geometry was the original source of the geofence into the event record ... you could use the geofence's name as the primary key for an attribute join and then use a Field Enricher to bring in the feature record's other attributes.
Normal field enrichment is attribute only. Your event record's attributes are used to create a virtual table. You specify which event attribute should be used as the primary key, which feature record attribute should be used as the foreign key, and which feature attributes you want to bring into the event record as part of the enrichment.
For your use case, you would have to first establish a fishnet of polygons whose center point was the average elevation for the area. Then you could GeoTag to determine which grid cell an incoming point was within, and Field Enrich to obtain the elevation information from the feature record(s) used to establish the fishnet of geofences.
If this is not practical, because you have a wide area of interest with significant elevation variation across the DEM and/or very small elevation grid cells, then you would probably have to use the GeoEvent Java SDK to develop a custom spatial join which could work directly with the DEM without having to first establish a feature set of polygons representing a fishnet over yout DEM.
- RJ
