An MKMapView subclass with clustering. Inspired by ADClusterMapView.

• Swift implementation
• Principal Components Analysis algorithm
• Full tree's depth on the map view
• Animations

• Annotation encapsulation: for performance reasons, each annotation is encapsulated in a Node to keep track of its children and parent. The original annotation can be retrieved in the node's annotation property.
• Since the goal is to display all the tree (current depth) on the map, performance is slightly reduced, but sufficient for most use cases.

• iOS 8.0+
• Swift 3.0+

platform :ios, '10.0'
use_frameworks!

target '<Your Target Name>' do
    pod 'ClusterMapView'
end

1. Replace your MKMapView instance by a ClusterMapView instance.

2. Add annotations using setAnnotations.

As annotations are now encapsulated in nodes, you can observe each Node's type property to adjust annotation views accordingly.

func mapView(_ mapView: MKMapView, viewFor annotation: MKAnnotation) -> MKAnnotationView? {
    if let node = annotation as? Node {
        var pin: MKPinAnnotationView!
        if let dequeued = mapView.dequeueReusableAnnotationView(withIdentifier: "pin") as? MKPinAnnotationView {
            pin = dequeued
            pin.annotation = node
        } else {
            pin = MKPinAnnotationView(annotation: node, reuseIdentifier: "pin")
        }
        switch node.type {
        case .leaf:
            pin.pinTintColor = .green
        case .node:
            pin.pinTintColor = .blue
        case .root:
            pin.pinTintColor = .red
        }
        return pin
    }
    return nil
}

ClusterMapView adds additional methods on MKMapViewDelegate.

Customize the maximum number of nodes that you want to see on your map:

var numberOfVisibleNodes: Int { get } // default 32

Customize the animation duration:

var animationDuration: Double { get } // default 0.4

Events:

func mapViewDidFinishClustering(_ mapView: MKMapView)
    
func mapViewDidFinishAnimating(_ mapView: MKMapView)