Hey @NateRogers1 ,
I would recommend using the Detect Incidents tool here, as you can use a Spatial Relationship of "Within" as Jeff mentioned. This tool will also allow you to configure any other attribute/temporal relationships you may be interested in for this join.
In your scenario, the points feed will be connected to the target port of the Detect Incidents tool and the polygon feed will be connected to the join port. If your polygon features have an "End Time" key field configured, these features will automatically be removed from the Detect Incidents tool's cache when they expire. If you do not have a field that can be used to expire these polygons, these features will expire based on the value set for the Join Time Window parameter. Ex: if you set this value to 1 hour, incidents can be detected if they are within a polygon for 1 hour after the polygon is ingested, after which it will be removed from the cache (incidents will no longer be detected based on this polygon feature UNLESS a new feature with the same Track ID field has been ingested). If you have an End Time key field set, no incidents will be detected based on a polygon feature after it's End Time value is met.
If you are not necessarily interested in knowing how long a point feature has been within a polygon, the Filter by Geometry or Join Features tools could meet your needs, as they support "WITHIN" for spatial relationship. Keep in mind that in dynamic geofencing configurations (feed attached to both the target port and the join port), you will want to configure the Join Time Window parameter to ensure you are only analyzing active polygons as I've described above in relation to Detect Incidents.
Also worth noting - using "Intersects" for any of the above tools would be less compute intensive than "Within". If "Intersects" would meet the same need, I would recommend using this instead.
