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Annotations

Annotations are images or individually-styled circles, lines, or polygon features that are rendered above the map and fixed to specific geographic coordinates.

Benefits:

  • Built-in interaction support.
  • No specific data format other than geographic coordinates (longitude and latitude).
  • Every annotation can be individually styled.
  • Every annotation layer can be adjusted to be above or below another layer.
  • Same performance benefits as using style layers.

Limitations:

  • No default image available.
  • Inefficient for adding many features to the map.

In SwiftUI, add annotations to the map by including them in the Map block. Annotations conform to MapContent, which means they can be added directly to the map view. You can create and add individual instances of different annotation types, such as PointAnnotation, CircleAnnotation, PolylineAnnotation, and PolygonAnnotation.

Point annotations (Markers)​

A PointAnnotation can display an image at any geographic coordinate. A common use case is to display a marker or pin representing a location that a user can tap on to get more information.

PointAnnotation works with any UIImage, so the compatible image formats include PNG, JPEG, GIF, TIFF, HEIC/HEIF, and PDF.

Bring your own image

The Maps SDK for iOS does not provide a default image for point annotations. You must provide your own image asset.

The code snippet below shows how to add a point annotation to the map using an image asset named dest-pin. You can download a PDF containing a red map marker to try out the PointAnnotation example.

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Map {
  let someCoordinate = CLLocationCoordinate2D(latitude: 40.7128, longitude: -74.0060)
  PointAnnotation(coordinate: someCoordinate)
    .image(.init(image: UIImage(named: "dest-pin")!, name: "dest-pin"))
}
EXAMPLE
Add a marker to the map

Use MapView's AnnotationOrchestrator class to add a single red marker pin to the map using the Maps SDK for iOS.

Other shapes​

MapView’s AnnotationOrchestrator also supports putting other shapes on the map including circles using CircleAnnotationManager, polylines using PolylineAnnotationManager, and polygons using PolygonAnnotationManager. These annotations work like the point annotations described above, but do not require an image. The options available for each type of annotation varies and you can find a full list in the API reference documentation.

Circle annotation​

A circle annotation (CircleAnnotation) places a circle at a point on the map.

Map {
  let circleCoordinate = CLLocationCoordinate2DMake(40.7128, -74.0060)
  CircleAnnotation(centerCoordinate: circleCoordinate)
    .circleColor(.red)
}
EXAMPLE
Add circle annotations

To create the image below, use MapView's AnnotationOrchestrator class to add many colored circles to the map using the Maps SDK for iOS.

Polyline annotation​

A polyline annotation (PolylineAnnotation) connects a list of coordinates on the map with a polyline. The order of the coordinates in the list will determine the order in which to connect the points, in the same way that coordinates are handled in the GeoJSON specification.

Map {
  // Define two or more geographic coordinates to connect with a line.
  // Line from New York City, NY to Washington, D.C.
  let lineCoordinates = [
      CLLocationCoordinate2DMake(40.7128, -74.0060),
      CLLocationCoordinate2DMake(38.9072, -77.0369)
  ]

  PolylineAnnotation(lineCoordinates: lineCoordinates)
    .lineColor(.red)
}
EXAMPLE
Add polyline annotations

To create the image below, use MapView's AnnotationOrchestrator class to add many polylines to the map using the Maps SDK for iOS.

Polygon annotation​

A polygon annotation (PolygonAnnotation) takes a list of coordinates and will try to connect those coordinates and add the resulting polygonal shape to the map. The order of the coordinates in the list matters and works the same way as in the GeoJSON specification.

Map {
  // Define three or more geographic coordinates to connect.
  let ring = Ring(coordinates: [
      CLLocationCoordinate2DMake(24.5171, -89.8571),
      CLLocationCoordinate2DMake(24.5171, -87.9675),
      CLLocationCoordinate2DMake(26.2441, -87.9675),
      CLLocationCoordinate2DMake(26.2441, -89.8571),
      CLLocationCoordinate2DMake(24.5171, -89.8571)
  ])

  PolygonAnnotation(polygon: Polygon(outerRing: ring))
}
EXAMPLE
Add a polygon to the map

To create the image below, use MapView's AnnotationOrchestrator class to add a single red polygon annotation to the map using the Maps SDK for iOS.

Interactivity​

The Map content gestures allow you to assign Tap and Long Press gestures handlers to Annotations, Layers, and the Map. The handlers are called according to the rendered layer position starting from the top-most.

Map {
  PolygonAnnotation(...)
    .onTapGesture { context in
      print("tapped point annotation at \(context.coordinate)")
      return true // Don't propagate the event to objects below
    }
}

Removing Annotations​

To remove an annotation, call remove(at:) or removeAll() on the annotation manager's annotations property.

// Create an circleAnnotationManager to handle circle annotations
let annotationManager = mapView.annotations.makeCircleAnnotationManager()

// Add a circle annotation
let circle = CircleAnnotation(...)
annotationManager.annotations.append(circle)

// Remove the circle annotation by its index
annotationManager.annotations.remove(at: 0)

// Remove the circle annotation by its id
annotationManager.annotations.removeAll { $0.id == circle.id }

// Remove all annotations managed by this annotation manager
annotationManager.annotations.removeAll()

To remove an annotation manager, call mapView.annotations.removeAnnotationManager(withId:), passing the ID of the annotation manager that you want to remove. This removes the backing source and layer. The removed annotation manager will not be useful after it is removed.

An id can be specified when creating an annotation manager by passing an id parameter to the makeXAnnotationManager(id:) method. If no id is specified, a unique id will be generated automatically. You can retrieve the id of an existing annotation manager using its id property.

Annotation managers are removed implicitly if another annotation manager is created with the same ID.

// Create an polygonAnnotationManager to handle polygon annotations
let annotationManager = mapView.annotations.makePolygonAnnotationManager(id: "my-polygon-manager")

// add annotations to the manager

...

// Later, when you want to remove the annotation manager and its annotations
mapView.annotations.removeAnnotationManager(withId: "my-polygon-manager")
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