Swift attach UIView to PolyLine and follow angle - ios

Question

I'm attempting to have a UIView follow a Polyline using the angle of the Polyline. The problem I'm facing is the rotation is never right unless the angle is lower than 50 degrees, which I'm thinking is just a coincidence. How can I get the rotation to follow the line?
Here's the code I'm using to detect the rotation.
func heading(from: MSGeopoint, to: MSGeopoint) -> Double {
let a = CLLocationCoordinate2D(latitude: from.position.latitude, longitude: from.position.longitude)
let b = CLLocationCoordinate2D(latitude: to.position.latitude, longitude: to.position.longitude)
let lat1 = a.latitude.degreesToRadians
let lon1 = a.longitude.degreesToRadians
let lat2 = b.latitude.degreesToRadians
let lon2 = b.longitude.degreesToRadians
let dLon = lon2 - lon1
let y = sin(dLon) * cos(lat2)
let x = cos(lat1) * sin(lat2) - sin(lat1) * cos(lat2) * cos(dLon)
let headingDegrees = atan2(y, x).radiansToDegrees
if headingDegrees >= 0 {
print("\(headingDegrees)")
return headingDegrees
} else {
print("\(headingDegrees + 360)")
return headingDegrees + 360
}
}
The MSGeoPoint is primarily a wrapper for CoreLocation using Bing maps but here's how you instantiate the from and to.
let fromGeoPoint = MSGeopoint(latitude: from.latitude, longitude: from.longitude)
let toGeoPoint = MSGeopoint(latitude: to.latitude, longitude: to.longitude)
And the degreesToRadians.
extension BinaryInteger {
var degreesToRadians: CGFloat { return CGFloat(Int(self)) * .pi / 180 }
}
Here's also how I'm creating the view.
func createDistanceView() -> UIView {
let distanceView: DistanceView = UIView.fromNib()
distanceView.layer.borderColor = UIColor(named: "Blue")?.cgColor ?? UIColor.blue.cgColor
distanceView.layer.borderWidth = 3
distanceView.layer.masksToBounds = true
let heading = heading(from: from, to: to).rounded(.toNearestOrAwayFromZero)
distanceView.distanceLabel.text = "Your almost there"
return distanceView
}