Feature querying methods should return Turf.Feature, not MapboxCommon.Feature

[1ec5]

MapboxMap’s feature querying methods’ callbacks should accept Turf.Features as arguments, not MapboxCommon.Features. Otherwise, there’s no way for the developer to work with the results in other Mapbox products such as MapboxDirections or MapboxNavigation.

mapbox-maps-ios/Sources/MapboxMaps/Foundation/MapboxMap.swift

Lines 379 to 381 in c622444

	// TODO: Turf feature property of QueriedFeature
	extension MapboxMap: MapFeatureQueryable {
	public func queryRenderedFeatures(for shape: [CGPoint], options: RenderedQueryOptions? = nil, completion: @escaping (Result<[QueriedFeature], Error>) -> Void) {

At a glance, it seems like the code would simply need to map the results to this convenience initializer:

mapbox-maps-ios/Sources/MapboxMaps/Foundation/Extensions/Turf/Feature.swift

Line 11 in c622444

internal init?(_ feature: MapboxCommon.Feature) {

/cc @mapbox/maps-ios @ZiZasaurus @mapbox/navigation-ios

[bmt2018]

I was confused by this, as well. My GeoJSON source is a feature collection created from an array of Turf.Feature objects. But when querying for the rendered feature that was tapped on, I'm getting back an array of QueriedFeature which use instances of MapboxCommon.Feature. I was trying to cast MapboxCommon.Feature to Turf.Feature or to be able to init Turf.Feature using MapboxCommon.Feature but couldn't get either to work.

[nkdem]

I was confused by this, as well. My GeoJSON source is a feature collection created from an array of Turf.Feature objects. But when querying for the rendered feature that was tapped on, I'm getting back an array of QueriedFeature which use instances of MapboxCommon.Feature. I was trying to cast MapboxCommon.Feature to Turf.Feature or to be able to init Turf.Feature using MapboxCommon.Feature but couldn't get either to work.

I ran into the same issue so a workaround I used was something Mapbox's 'internal' code does:

mapbox-maps-ios/Sources/MapboxMaps/Foundation/Extensions/Turf/Geometry.swift

Lines 8 to 20 in 453577d

	extension Turf.Geometry {
	/// Allows a Turf object to be initialized with an internal `Geometry` object.
	/// - Parameter geometry: The `Geometry` object to transform.
	internal init?(_ geometry: MapboxCommon.Geometry) {
	switch geometry.geometryType {
	case GeometryType_Point:
	guard let coordinate = geometry.extractLocations()?.coordinateValue() else {
	return nil
	}
	self = Turf.Geometry.point(Point(coordinate))

So for example, in my application I need access to the feature's geometry type however, mapbox's feature only returns an integer and I'd prefer a more readable format i.e., a String which Turf provides. I created a function:

// Convert from Mapbox geometry type to Turfs
	static func convertGeometryType(geometry: MapboxMaps.GeometryType) -> Turf.GeometryType? {
		switch geometry {
		case GeometryType_Point:
			return Turf.GeometryType.Point
		// ... You get the gist
	}

Hope that helps @bmt2018

---

Anyway, I think there should be more consistency in the querying methods to prevent from having to do workarounds like this. And by consistency what I mean is that some functionality relies on Turf.Feature whereas some on Mapbox's feature.

[bmt2018]

@nbieniek Thank you for the suggestion! I ended up doing something very similar as a workaround for now. I also hope that they'll make this more consistent in a future build of the SDK.

[macdrevx]

We plan to do this by refining FeatureExtensionValue.featureCollection and QueriedFeature.feature so that their types are Turf types instead of the current MBXFeature-based types.

[macdrevx]

Resolved by #717 and #628