Hello David -
I'd like to make sure I understand your question or scenario. You would like the ability to configure a filter element with an expression similar to GEOMETRY OUTSIDE FlightZones/${ZoneID} rather than naming a specific GeoFence such as GEOMETRY OUTSIDE FlightZones/ZoneA.
This isn't supported in the current release. The spatial expression for a filter element (or Incident Detector processor element) will not substitute a value (e.g. an attribute value) for a variable (e.g. the name of an event field) on-the-fly as the expression is evaluated by the filter / processor when an event is received. The spatial expression must include the GeoFence category and a GeoFence name. Regular expression patterns are accepted, so an expression such as GEOMETRY OUTSIDE FlightZones/.* is valid.
What you can do, at the 10.2.1 release, is combine a GeoTagger with a Filter in order to generate an alert when an asset is tagged outside of its assigned zone. For example, if you configured a GeoTagger processor to enrich events with just the name of the GeoFence they are found INSIDE, you could then configure a filter which checked to see if the name of the asset's assigned zone did not match the name of the zone in which it was most recently tagged. Something like the attached illustration. (Notice that I did not include the name of the GeoFence Category in the GeoTagger's enrichment, so I can use variable-substitution to compare the value from the field ZoneID (where the flight is supposed to be) with the value in the GeoTag field TaggedInZone.
Hope this helps -
RJ
