MGLPolygon

 

@interface MGLPolygon : MGLMultiPoint <MGLOverlay>

An MGLPolygon object represents a closed shape consisting of four or more vertices, specified as CLLocationCoordinate2D instances, and the edges that connect them. For example, you could use a polygon shape to represent a building, a lake, or an area you want to highlight.

You can add polygon shapes to the map by adding them to an MGLShapeSource object. Configure the appearance of an MGLShapeSource’s or MGLVectorTileSource’s polygons collectively using an MGLFillStyleLayer or MGLSymbolStyleLayer object. To access a polygon’s attributes, use an MGLPolygonFeature object.

Alternatively, you can add a polygon overlay directly to a map view using the -[MGLMapView addAnnotation:] or -[MGLMapView addOverlay:] method. Configure a polygon overlay’s appearance using -[MGLMapViewDelegate mapView:strokeColorForShapeAnnotation:] and -[MGLMapViewDelegate mapView:fillColorForPolygonAnnotation:].

The vertices are automatically connected in the order in which you provide them. You should close the polygon by specifying the same CLLocationCoordinate2D as the first and last vertices; otherwise, the polygon’s fill may not cover the area you expect it to. To avoid filling the space within the shape, give the polygon a transparent fill or use an MGLPolyline object.

A polygon may have one or more interior polygons, or holes, that you specify as MGLPolygon objects with the +polygonWithCoordinates:count:interiorPolygons: method. For example, if a polygon represents a lake, it could exclude an island within the lake using an interior polygon. Interior polygons may not themselves have interior polygons. To represent a shape that includes a polygon within a hole or, more generally, to group multiple polygons together in one shape, use an MGLMultiPolygon or MGLShapeCollection object.

To make the polygon straddle the antimeridian, specify some longitudes less than −180 degrees or greater than 180 degrees.

See the Add a polygon annotation example to learn how to initialize an MGLPolygon object from an array of coordinates.

  • The array of polygons nested inside the receiver.

    The area occupied by any interior polygons is excluded from the overall shape. Interior polygons should not overlap. An interior polygon should not have interior polygons of its own.

    If there are no interior polygons, the value of this property is nil.

    Declaration

    Objective-C

    @property (nonatomic, readonly, nullable) NSArray<MGLPolygon *> *interiorPolygons;

    Swift

    var interiorPolygons: [MGLPolygon]? { get }
    View Source on GitHub

  • Creates and returns an MGLPolygon object from the specified set of coordinates.

    Declaration

    Objective-C

    + (nonnull instancetype)polygonWithCoordinates:
                            (nonnull const CLLocationCoordinate2D *)coords
                                         count:(NSUInteger)count;

    Swift

    convenience init(coordinates coords: UnsafePointer<CLLocationCoordinate2D>, count: UInt)

    Parameters

    coords

    The array of coordinates defining the shape. The data in this array is copied to the new object.
    count

    The number of items in the coords array.

    Return Value

    A new polygon object.

    View Source on GitHub

  • Creates and returns an MGLPolygon object from the specified set of coordinates and interior polygons.

    Declaration

    Objective-C

    + (nonnull instancetype)
    polygonWithCoordinates:(nonnull const CLLocationCoordinate2D *)coords
                     count:(NSUInteger)count
          interiorPolygons:(nullable NSArray<MGLPolygon *> *)interiorPolygons;

    Swift

    convenience init(coordinates coords: UnsafePointer<CLLocationCoordinate2D>, count: UInt, interiorPolygons: [MGLPolygon]?)

    Parameters

    coords

    The array of coordinates defining the shape. The data in this array is copied to the new object.
    count

    The number of items in the coords array.
    interiorPolygons

    An array of MGLPolygon objects that define regions excluded from the overall shape. If this array is nil or empty, the shape is considered to have no interior polygons.

    Return Value

    A new polygon object.

    View Source on GitHub