Skip to main content

Areas alarms

Last updated: April 3, 2026 | 2 minutes read

Trigger operations when users enter or exit defined geographic areas using the AlarmContext.

Add areas to monitor​

Define geographic areas and call monitorArea(_:areaId:) on your AlarmContext instance. You can monitor three types: RectangleGeographicAreaObject, CircleGeographicAreaObject, and PolygonGeographicAreaObject.

Assign a unique string identifier to each area so you can determine which zone a user has entered or exited:

let topLeft = CoordinatesObject.coordinates(withLatitude: 1, longitude: 0.5)
let bottomRight = CoordinatesObject.coordinates(withLatitude: 0.5, longitude: 1)
let rect = RectangleGeographicAreaObject(topLeftLocation: topLeft, bottomRightLocation: bottomRight)

let center = CoordinatesObject.coordinates(withLatitude: 1, longitude: 0.5)
let circle = CircleGeographicAreaObject(center: center, radius: 100)

let points = [
    CoordinatesObject.coordinates(withLatitude: 1, longitude: 0.5),
    CoordinatesObject.coordinates(withLatitude: 0.5, longitude: 1),
    CoordinatesObject.coordinates(withLatitude: 1, longitude: 1),
    CoordinatesObject.coordinates(withLatitude: 1, longitude: 0.5), // close the polygon
]
let polygon = PolygonGeographicAreaObject(coordinates: points)

alarmContext?.monitorArea(rect, areaId: "areaRect")
alarmContext?.monitorArea(circle, areaId: "areaCircle")
alarmContext?.monitorArea(polygon, areaId: "areaPolygon")
Tip

When defining a PolygonGeographicAreaObject, always close the shape by making the first and last coordinates identical. Otherwise, the SDK may not match the polygon you provided.

Unmonitor an area​

Remove a monitored area by passing the same GeographicAreaObject instance used in monitorArea(_:areaId:):

alarmContext?.unmonitorArea(rect)

Remove multiple areas by passing an array of their identifiers:

alarmContext?.unmonitorAreas(["areaRect", "areaCircle"])

Remove all monitored areas:

alarmContext?.unmonitorAllAreas()

Get notified when users enter or exit areas​

Implement alarmContext(onBoundaryCrossed:enteredArea:exitedAreas:) in your AlarmContextDelegate. The callback provides arrays of AlarmMonitoredAreaObject for entered and exited areas:

func alarmContext(onBoundaryCrossed alarmContext: AlarmContext,
                  enteredArea arrayIn: [AlarmMonitoredAreaObject],
                  exitedAreas arrayOut: [AlarmMonitoredAreaObject]) {
    for area in arrayIn {
        print("Entered area: \(area.getMonitorIdentifier())")
    }
    for area in arrayOut {
        print("Exited area: \(area.getMonitorIdentifier())")
    }
}

Retrieve the geographic area from an AlarmMonitoredAreaObject using getMonitorGeographicArea().

Last updated on