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?

score 71 · Answer 1 · edited Jan 15 '15 at 22:55

71

-(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];
}

edited Jan 15 '15 at 22:55

devios1

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answered Sep 27 '13 at 03:18

fundtimer

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@BradKoch This solution uses `boundingMapRect` to define a rectangle that encompasses the polyline overlay. It then sets the map zoom area to that rectangle with `setVisibleMapRect` taking into account the adjustable padding values with `edgePadding`. I found this solution to be the most helpful, since it solves the problem efficiently with few lines of code and also allows for changes to the map view area through insets. – sheepgobeep Jun 04 '14 at 09:01
2

This works for me. But apparently this sets the zoom factor to **fill** the screen, instead of **fit**. Can you think of a solution for that – Julian F. Weinert Oct 24 '14 at 02:25
Plus one for a solution with insets. – gotnull Mar 05 '15 at 05:48
Good solution +1. Only thing is that Padding needs to be adjusted as per visual needs, that way it will support all the other overlays. – iLearner Jul 25 '17 at 06:48

score 15 · Answer 2 · answered Feb 04 '13 at 21:51

15

-(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];
}

answered Feb 04 '13 at 21:51

Tom

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It is not required to create a MKPolygon as MKPolyline already implement boundingMapRect – foOg Oct 29 '14 at 09:28
how are you assigning fence to CLLocation ?? means in goefencing how to you allocate that CLregion instead of circular region??? – Majid Bashir Feb 04 '16 at 04:06

score 15 · Answer 3 · answered Dec 07 '15 at 18:17

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

score 10 · Answer 4 · edited May 23 '17 at 10:31

10

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

edited May 23 '17 at 10:31

Community

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answered Nov 26 '12 at 20:45

Craig

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I owe you a beer for that :) – Devarshi Jan 14 '15 at 08:18
MKMapRectUnion link is broken, here's the new page https://developer.apple.com/documentation/mapkit/1452123-mkmaprectunion – Marco Boschi Apr 29 '18 at 13:07

score 9 · Answer 5 · answered Mar 17 '17 at 10:45

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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)
    }

answered Mar 17 '17 at 10:45

Burf2000

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Swift 5 version: the second line of code from above changes a bit: let rect = self.mapView.overlays.reduce(first.boundingMapRect, {$0.union($1.boundingMapRect)}) } – cseh_17 Jan 19 '22 at 09:05

score 9 · Answer 6 · answered Nov 15 '17 at 07:55

Swift 4 / slightly modified version of fundtimer's answer.

 func setVisibleMapArea(polyline: MKPolyline, edgeInsets: UIEdgeInsets, animated: Bool = false) {
    mapView.setVisibleMapRect(polyline.boundingMapRect, edgePadding: edgeInsets, animated: animated)
}

Calling the above using a route's polyline and leaving the default of not animated, and adding small edge insets of 10 all around:

setVisibleMapArea(polyline: route.polyline, edgeInsets: UIEdgeInsetsMake(10.0, 10.0, 10.0, 10.0))

score 1 · Answer 7 · answered Feb 01 '19 at 04:56

I have another solution for this problem

private func mapRegion() -> MKCoordinateRegion? {


    let latitudes = self.coordinates.map { location -> Double in

        return location.latitude
    }

    let longitudes = self.coordinates.map { location -> Double in

        return location.longitude
    }

    let maxLat = latitudes.max()!
    let minLat = latitudes.min()!
    let maxLong = longitudes.max()!
    let minLong = longitudes.min()!

    let center = CLLocationCoordinate2D(latitude: (minLat + maxLat) / 2,
                                        longitude: (minLong + maxLong) / 2)
    let span = MKCoordinateSpan(latitudeDelta: (maxLat - minLat) * 1.3,
                                longitudeDelta: (maxLong - minLong) * 1.3)
    return MKCoordinateRegion(center: center, span: span)
}

Where coordinates is Array of CLLocationCoordinate2D

Hope it is helpful to someone

score 0 · Answer 8 · answered Jul 25 '17 at 06:54

@Fundtimer pointed it right way, Only thing is that Padding needs to be adjusted as per visual needs, that way it will support all the other overlays and following is the generic solution for all overlays.

-(void)zoomIntoExistingMapObjectForAnnot:(CustomMapAnnotation *)annot
{
   id overlay = annot.shape;//I have overlay property in custom annotation class.
   [_mapView setVisibleMapRect:[overlay boundingMapRect] edgePadding:UIEdgeInsetsMake(150.0, 150.0, 150.0, 150.0) animated:YES];
}

Zoom MKMapView to fit polyline points

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