Zoom MKMapView to fit polyline points

Question

I have an array, allCollections, that holds programmatically-created arrays of CLLocations the user has recorded through my iOS app. Each sub-array in allCollections holds all the location points in a trip taken.

I draw MKPolylines off of the CLLocations in the arrays in allCollections to represent those trips on an MKMapView. My question is this: With the polylines added to the map, how would I go about programmatically zooming and centering the map to display all of them?

Solution 1

-(void)zoomToPolyLine: (MKMapView*)map polyline: (MKPolyline*)polyline animated: (BOOL)animated
{
    [map setVisibleMapRect:[polyline boundingMapRect] edgePadding:UIEdgeInsetsMake(10.0, 10.0, 10.0, 10.0) animated:animated];
}

Solution 2

-(void)zoomToPolyLine: (MKMapView*)map polyLine: (MKPolyline*)polyLine 
animated (BOOL)animated
{
MKPolygon* polygon = 
    [MKPolygon polygonWithPoints:polyLine.points count:polyLine.pointCount];

[map setRegion:MKCoordinateRegionForMapRect([polygon boundingMapRect]) 
     animated:animated];
}

Solution 3

in swift:

if let first = mapView.overlays.first {
    let rect = mapView.overlays.reduce(first.boundingMapRect, combine: {MKMapRectUnion($0, $1.boundingMapRect)})
    mapView.setVisibleMapRect(rect, edgePadding: UIEdgeInsets(top: 50.0, left: 50.0, bottom: 50.0, right: 50.0), animated: true)
}

this will zoom/pan to fit all overlays with a little buffer

Solution 4

You could loop through all CLLocations recording the max/min coordinates and use that to set a view rect like they do on this question iOS MKMapView zoom to show all markers .

Or you could go through each of your overlays and get their boundingMapRect then use MKMapRectUnion (http://developer.apple.com/library/ios/documentation/MapKit/Reference/MapKitFunctionsReference/Reference/reference.html#//apple_ref/c/func/MKMapRectUnion) to combine them all until you have one MKMapRect that covers them all and use that to set the view.

[mapView setVisibleMapRect:zoomRect animated:YES]

This question shows a simple loop combining the maprects in unions as I suggested: MKMapRect zooms too much

Solution 5

Swift 3 version of garafajon excellent code

    if let first = self.mapView.overlays.first {
        let rect = self.mapView.overlays.reduce(first.boundingMapRect, {MKMapRectUnion($0, $1.boundingMapRect)})
        self.mapView.setVisibleMapRect(rect, edgePadding: UIEdgeInsets(top: 50.0, left: 50.0, bottom: 50.0, right: 50.0), animated: true)
    }

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