The DistanceToGeofence() function determines the distance between an asset and the edge of a specified circular geofence.
Number DistanceToGeofence(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 evaluates to true if the asset location is greater than three miles from the boundary of the geofence.
If: DistanceToGeofence("42.3948532,-71.2938472", 2.5, Location.location) >3