What are Geofence Scopes?
Geofences in Perspio have to be set to the correct scope to ensure the expected behaviour.
Geofence Scopes Overview
This article explains what geofence scopes are in Perspio, the two scope types available (Global and Group), and how to choose the right one so that only the assets you intend will trigger entry and exit events for a geofence.
Background: geofences and events
A geofence (also called a zone) is an object made up of one or more GeoJSON polygons. Each polygon is a set of coordinates that defines a boundary — a geospatial shape that Perspio uses to determine whether any given location falls inside or outside the zone.
As asset telemetry streams into Perspio, every location coordinate reported by an asset is evaluated against all geofences in your tenant in real time. Based on that evaluation, Perspio generates entry and exit events.
How entry and exit events are triggered
- Entry event: Generated when two consecutive coordinates from an asset fall inside the geofence. The asset is then associated with that geofence.
- Exit event: Generated when two consecutive coordinates fall outside the geofence. There is also a fast-exit rule — a single coordinate that is both outside the geofence and more than 500 m from its centre will trigger an exit event on its own.
Requiring two consecutive coordinates before confirming an entry or exit helps filter out GPS noise, so a single stray reading near a boundary doesn't create a false event. The 500 m rule is a safeguard that registers an exit quickly when an asset has clearly moved well away from the zone.
What are geofence scopes?
A geofence's scope controls which assets are allowed to interact with it — that is, which assets are evaluated against the geofence and can trigger its entry and exit events. Setting the correct scope ensures a geofence behaves the way you expect.
Every geofence has one of two scopes:
| Scope | Which assets interact with the geofence | When it's set |
|---|---|---|
| Global (default) | Every location-enabled asset in the tenant | Applied automatically |
| Group | Only assets that belong to the associated asset group(s) | Set manually |
Global scope (default)
Global is the default scope. Every location-enabled asset in your tenant is evaluated against the geofence, and any asset can trigger entry and exit events.
Group scope
Group scope limits interaction to specific assets. When you set a geofence to Group scope, you also associate one or more asset groups with it. Only assets that are members of those groups are evaluated against the geofence and able to trigger entry and exit events — all other assets are ignored by that geofence.
Note: Group scope requires at least one asset group to be associated with the geofence. Without an associated group, no assets will interact with it.
When to use Group scope
Group scope is useful whenever you want a geofence to apply to only a subset of your fleet rather than every asset. For example:
- Customer-specific sites: Suppose your tenant has 1,000 assets, but only 10 of them service a particular customer. With Global scope, all 1,000 assets would generate entry and exit events at that customer's site. By setting the geofence to Group scope and associating only the relevant group, just those 10 assets interact with it.
- Condition-specific alerts: Suppose you create a geofence that sends an SMS notification when a vehicle speeds within it. You likely don't want off-road assets generating events there. Group scope lets you restrict the geofence to only the on-road vehicles the alert is meant for.
Managing group associations
The link between a geofence and its asset groups is a single shared membership framework, and you can view or edit it from either side:
- In the Geofences module, open a geofence to see and manage the groups associated with it.
- In the Groups module, open a group to see the geofences it's associated with.
These are two views of the same relationship, just from each object's perspective. A change made in one place is reflected in the other.
Need help?
Geofence scopes support a wide range of setups — for example, placing geofences around customer sites and tailoring alerts to the contacts registered in Perspio Asset Master. If you'd like help configuring scopes for your use case, or have any questions, reach out to us at servicedesk@perspio.io.