# MGLOverlay

    @protocol MGLOverlay <MGLAnnotation>

The `MGLOverlay` protocol defines a specific type of annotation that represents both a point and an area on a map. Overlay objects are essentially data objects that contain the geographic data needed to represent the map area. Overlays can take the form of a polyline or polygon.

You use overlays to layer more sophisticated content on top of a map view. For example, you could use an overlay to show the boundaries of a national park or trace a bus route along city streets. This SDK defines several concrete classes that conform to this protocol and define standard shapes.

- `coordinate`

  A coordinate representing the overlay. (required) (read-only)

  #### Declaration

  Objective-C

      @property (readonly, nonatomic) CLLocationCoordinate2D coordinate;

  Swift

      var coordinate: CLLocationCoordinate2D { get }

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- `overlayBounds`

  The cooordinate rectangle that encompasses the overlay. (required) (read-only)

  This property contains the smallest rectangle that completely encompasses the overlay. Implementers of this protocol must set this area when implementing their overlay class, and after setting it, you must not change it.

  If this overlay spans the antimeridian, its bounds may extend west of −180 degrees longitude or east of 180 degrees longitude. For example, an overlay covering the Pacific Ocean from Tokyo to San Francisco might have a bounds extending from (35.68476, −220.24257) to (37.78428, −122.41310).

  #### Declaration

  Objective-C

      @property (readonly, nonatomic) MGLCoordinateBounds overlayBounds;

  Swift

      var overlayBounds: MGLCoordinateBounds { get }

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- `-intersectsOverlayBounds:`

  Returns a Boolean indicating whether the specified rectangle intersects the receiver’s shape.

  You can implement this method to provide more specific bounds checking for an overlay. If you do not implement it, the bounding rectangle is used to detect intersections.

  #### Declaration

  Objective-C

      - (BOOL)intersectsOverlayBounds:(MGLCoordinateBounds)overlayBounds;

  Swift

      func intersects(_ overlayBounds: MGLCoordinateBounds) -> Bool

  #### Parameters

  `overlayBounds` | The rectangle to intersect with the receiver’s area.

  #### Return Value

  `YES` if any part of the map rectangle intersects the receiver’s shape or `NO` if it does not.

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