Where is MapKit Step polyline?

Question

I am trying to print coordinates of all route steps, similar to Google Maps SDK's "legs".

But it tells me that I cannot use polyline property to obtain a coordinate?

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score 2 · Accepted Answer · edited May 23 '17 at 12:28

Try this:

for step in self.route!.steps as [MKRouteStep] {

otherwise it treats step as AnyObject (which doesn't have a polyline property defined so you get that compiler error).

By the way, note that polyline.coordinate just gives the average center of the polyline or one endpoint. A polyline can have more than one line segment.

If you need to get all the line segments and coordinates along the polyline, see latitude and longitude points from MKPolyline (Objective-C).

Here's one possible translation to Swift (with help from this answer):

for step in route!.steps as [MKRouteStep] {
    let pointCount = step.polyline.pointCount

    var cArray = UnsafeMutablePointer<CLLocationCoordinate2D>.alloc(pointCount)

    step.polyline.getCoordinates(cArray, range: NSMakeRange(0, pointCount))

    for var c=0; c < pointCount; c++ {
        let coord = cArray[c]
        println("step coordinate[\(c)] = \(coord.latitude),\(coord.longitude)")
    }

    cArray.dealloc(pointCount)
}

As the first linked answer warns, you may get hundreds or thousands of coordinates per step depending on the route.

Swift is confusing. I can't seem to understand the need for optionals `?` and `!` and telling compiler to treat an object `as` some other type. Why can't a Swift be simple to use like JavaScript. — Sahat Yalkabov, Mar 02 '15 at 07:11
Thanks for the help, I was able to get coordinates from each step of the route. — Sahat Yalkabov, Mar 02 '15 at 07:14

score 1 · Answer 2 · edited Jul 11 '18 at 01:15

Swift 4.1, as of July 2018, based on the other answer.

let pointCount = step.polyline.pointCount
let cArray = UnsafeMutablePointer<CLLocationCoordinate2D>.allocate(capacity: pointCount)
step.polyline.getCoordinates(cArray, range: NSMakeRange(0, pointCount))

for c in 0..<pointCount {
    let coord = cArray[c]
    print("step coordinate[\(c)] = \(coord.latitude),\(coord.longitude)")
}

cArray.deallocate()

Where is MapKit Step polyline?

2 Answers2