DingiShapeSource

 

@interface DingiShapeSource : DingiSource

DingiShapeSource is a map content source that supplies vector shapes to be shown on the map. The shapes may be instances of MGLShape or DingiFeature, or they may be defined by local or external GeoJSON code. A shape source is added to an DingiStyle object along with an DingiVectorStyleLayer object. The vector style layer defines the appearance of any content supplied by the shape source. You can update a shape source by setting its shape or URL property.

DingiShapeSource is optimized for data sets that change dynamically and fit completely in memory. For large data sets that do not fit completely in memory, use the DingiComputedShapeSource or DingiVectorTileSource class.

Each geojson source defined by the style JSON file is represented at runtime by an DingiShapeSource 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 -[DingiStyle addSource:] and -[DingiStyle 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 = DingiPolylineFeature(coordinates: &coordinates, count: UInt(coordinates.count))
let source = DingiShapeSource(identifier: "lines", features: [polyline], options: nil)
mapView.style?.addSource(source)

Initializing a Source

Accessing a Source’s Content

  • 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 -[DingiStyle 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) DingiShape *shape;

    Swift

    @NSCopying var shape: DingiShape? { get set }
  • 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 }

  • 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 -[DingiMapView visibleFeaturesAtPoint:inStyleLayersWithIdentifiers:predicate:] or -[DingiMapView visibleFeaturesInRect:inStyleLayersWithIdentifiers:predicate:] method.

    Declaration

    Objective-C

    - (nonnull NSArray<id<DingiFeature>> *)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 DingiFeature protocol that represent features in the source that match the predicate.