MGLShapeSource


@interface MGLShapeSource : MGLSource

MGLShapeSource is a map content source that supplies vector shapes to be shown on the map. The shapes may be instances of MGLShape or MGLFeature, or they may be defined by local or external GeoJSON code. A shape source is added to an MGLStyle object along with an MGLVectorStyleLayer object. The vector style layer defines the appearance of any content supplied by the shape source.

Each geojson source defined by the style JSON file is represented at runtime by an MGLShapeSource object that you can use to refine the map’s content and initialize new style layers. You can also add and remove sources dynamically using methods such as -[MGLStyle addSource:] and -[MGLStyle sourceWithIdentifier:].

Any vector style layer initialized with a shape source should have a nil value in its sourceLayerIdentifier property.

Example

var coordinates: [CLLocationCoordinate2D] = [
    CLLocationCoordinate2D(latitude: 37.77, longitude: -122.42),
    CLLocationCoordinate2D(latitude: 38.91, longitude: -77.04),
]
let polyline = MGLPolylineFeature(coordinates: &coordinates, count: UInt(coordinates.count))
let source = MGLShapeSource(identifier: "lines", features: [polyline], options: nil)
mapView.style?.addSource(source)

Initializing a Source


                    
                    
                    -initWithIdentifier:URL:options:

Returns a shape source with an identifier, URL, and dictionary of options for the source.

Declaration

Objective-C

- (nonnull instancetype)
initWithIdentifier:(nonnull NSString *)identifier
               URL:(nonnull NSURL *)url
           options:(nullable NSDictionary<MGLShapeSourceOption, id> *)options;

Swift

init(identifier: String, url: URL, options: [MGLShapeSourceOption : Any]? = nil)

Parameters

`identifier`	A string that uniquely identifies the source.
`url`	An HTTP(S) URL, absolute file URL, or local file URL relative to the current application’s resource bundle.
`options`	An `NSDictionary` of options for this source.

Return Value

An initialized shape source.

View Source on GitHub


                    
                    
                    -initWithIdentifier:shape:options:

Returns a shape source with an identifier, a shape, and dictionary of options for the source.

To specify attributes about the shape, use an instance of an MGLShape subclass that conforms to the MGLFeature protocol, such as MGLPointFeature. To include multiple shapes in the source, use an MGLShapeCollection or MGLShapeCollectionFeature object, or use the -initWithIdentifier:features:options: or -initWithIdentifier:shapes:options: methods.

To create a shape from GeoJSON source code, use the +[MGLShape shapeWithData:encoding:error:] method.

Declaration

Objective-C

- (nonnull instancetype)
initWithIdentifier:(nonnull NSString *)identifier
             shape:(nullable MGLShape *)shape
           options:(nullable NSDictionary<MGLShapeSourceOption, id> *)options;

Swift

init(identifier: String, shape: MGLShape?, options: [MGLShapeSourceOption : Any]? = nil)

Parameters

`identifier`	A string that uniquely identifies the source.
`shape`	A concrete subclass of `MGLShape`
`options`	An `NSDictionary` of options for this source.

Return Value

An initialized shape source.

View Source on GitHub


                    
                    
                    -initWithIdentifier:features:options:

Returns a shape source with an identifier, an array of features, and a dictionary of options for the source.

Unlike -initWithIdentifier:shapes:options:, this method accepts MGLFeature instances, such as MGLPointFeature objects, whose attributes you can use when applying a predicate to MGLVectorStyleLayer or configuring a style layer’s appearance.

To create a shape from GeoJSON source code, use the +[MGLShape shapeWithData:encoding:error:] method.

Declaration

Objective-C

- (nonnull instancetype)
initWithIdentifier:(nonnull NSString *)identifier
          features:(nonnull NSArray<MGLShape<MGLFeature> *> *)features
           options:(nullable NSDictionary<MGLShapeSourceOption, id> *)options;

Swift

convenience init(identifier: String, features: [MGLShape], options: [MGLShapeSourceOption : Any]? = nil)

Parameters

`identifier`	A string that uniquely identifies the source.
`features`	An array of objects that conform to the MGLFeature protocol.
`options`	An `NSDictionary` of options for this source.

Return Value

An initialized shape source.

View Source on GitHub


                    
                    
                    -initWithIdentifier:shapes:options:

Returns a shape source with an identifier, an array of shapes, and a dictionary of options for the source.

Any MGLFeature instance passed into this initializer is treated as an ordinary shape, causing any attributes to be inaccessible to an MGLVectorStyleLayer when evaluating a predicate or configuring certain layout or paint attributes. To preserve the attributes associated with each feature, use the -initWithIdentifier:features:options: method instead.

To create a shape from GeoJSON source code, use the +[MGLShape shapeWithData:encoding:error:] method.

Declaration

Objective-C

- (nonnull instancetype)
initWithIdentifier:(nonnull NSString *)identifier
            shapes:(nonnull NSArray<MGLShape *> *)shapes
           options:(nullable NSDictionary<MGLShapeSourceOption, id> *)options;

Swift

convenience init(identifier: String, shapes: [MGLShape], options: [MGLShapeSourceOption : Any]? = nil)

Parameters

`identifier`	A string that uniquely identifies the source.
`shapes`	An array of shapes; each shape is a member of a concrete subclass of MGLShape.
`options`	An `NSDictionary` of options for this source.

Return Value

An initialized shape source.

View Source on GitHub

Accessing a Source’s Content

shape
The contents of the source. A shape can represent a GeoJSON geometry, a feature, or a collection of features.

If the receiver was initialized using -initWithIdentifier:URL:options:, this property is set to nil. This property is unavailable until the receiver is passed into -[MGLStyle addSource:].

You can get/set the shapes within a collection via this property. Actions must be performed on the application’s main thread.
Declaration
Objective-C

@property (readwrite, copy, nonatomic, nullable) MGLShape *shape;
Swift

@NSCopying var shape: MGLShape? { get set }
View Source on GitHub
URL
The URL to the GeoJSON document that specifies the contents of the source.

If the receiver was initialized using -initWithIdentifier:shape:options:, this property is set to nil.
Declaration
Objective-C

@property (readwrite, copy, nonatomic, nullable) NSURL *URL;
Swift

var url: URL? { get set }
View Source on GitHub


                    
                    
                    -featuresMatchingPredicate:

Returns an array of map features for this source, filtered by the given predicate.

Each object in the returned array represents a feature for the current style and provides access to attributes specified via the shape property.

Features come from tiled GeoJSON data that is converted to tiles internally, so feature geometries are clipped at tile boundaries and features may appear duplicated across tiles. For example, suppose this source contains a long polyline representing a road. The resulting array includes those parts of the road that lie within the map tiles that the source has loaded, even if the road extends into other tiles. The portion of the road within each map tile is included individually.

Returned features may not necessarily be visible to the user at the time they are loaded: the style may lack a layer that draws the features in question. To obtain only visible features, use the -[MGLMapView visibleFeaturesAtPoint:inStyleLayersWithIdentifiers:predicate:] or -[MGLMapView visibleFeaturesInRect:inStyleLayersWithIdentifiers:predicate:] method.

Declaration

Objective-C

- (nonnull NSArray<id<MGLFeature>> *)featuresMatchingPredicate:
    (nullable NSPredicate *)predicate;

Parameters


                                  predicate

A predicate to filter the returned features. Use nil to include all features in the source.

Return Value

An array of objects conforming to the MGLFeature protocol that represent features in the source that match the predicate.

View Source on GitHub