The InGeofence() function determines if a location is within a specified, circular geofence. Note that any location on the boundary is considered inside the geofence.
Boolean InGeofence(String center, Number radius, String location)
where:
center - latitude, longitude of the center of the geofence ; e.g., "42.3948532,-71.2938472".
radius - radius (miles) from the center - this defines the edge of the geofence.
location - location of the asset. For a MobileLocation trigger, you can specify an unqualified "location". For all other triggers, you need to qualify this as "Location.location".
The following expression returns true if the location is within 2.5 miles (the radius) of the given point.
If: InGeofence("42.3948532,-71.2938472", 2.5, Location.location)