MKMapView中心和放大

Question

我在一个项目上使用MKMapView,并希望将地图置于坐标上并放大.就像谷歌地图有:

GMSCameraPosition.camera(withLatitude: -33.8683,
                                  longitude: 151.2086,
                                  zoom: 6)

有没有Mapkit方法呢？

Answer 1

您将创建一个MKCoordinateRegion对象并将其设置为MKMapView对象上的区域.

MKCoordinateRegion mapRegion;   
CLLocationCoordinate2D coordinate;
coordinate.latitude = 0;
coordinate.longitude = 0;    
mapRegion.center = coordinate;
mapRegion.span.latitudeDelta = 0.2;
mapRegion.span.longitudeDelta = 0.2;

[mapView setRegion:mapRegion animated: YES];

Answer 2

这是我用于将地图置于预定义CLLocation使用中心的方法MKCoordinateRegion.

func centerMapOnLocation(_ location: CLLocation, mapView: MKMapView) {
    let regionRadius: CLLocationDistance = 1000
    let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate,
        regionRadius * 2.0, regionRadius * 2.0)
    mapView.setRegion(coordinateRegion, animated: true)
}

Answer 3

代码基于：http : //troybrant.net/blog/2010/01/set-the-zoom-level-of-an-mkmapview/

    extension MKMapView {
    var MERCATOR_OFFSET : Double {
        return 268435456.0
    }

    var MERCATOR_RADIUS : Double  {
        return 85445659.44705395
    }

    private func longitudeToPixelSpaceX(longitude: Double) -> Double {
        return round(MERCATOR_OFFSET + MERCATOR_RADIUS * longitude * M_PI / 180.0)
    }

    private func latitudeToPixelSpaceY(latitude: Double) -> Double {
        return round(MERCATOR_OFFSET - MERCATOR_RADIUS * log((1 + sin(latitude * M_PI / 180.0)) / (1 - sin(latitude * M_PI / 180.0))) / 2.0)
    }

    private  func pixelSpaceXToLongitude(pixelX: Double) -> Double {
        return ((round(pixelX) - MERCATOR_OFFSET) / MERCATOR_RADIUS) * 180.0 / M_PI;
    }

    private func pixelSpaceYToLatitude(pixelY: Double) -> Double {
        return (M_PI / 2.0 - 2.0 * atan(exp((round(pixelY) - MERCATOR_OFFSET) / MERCATOR_RADIUS))) * 180.0 / M_PI;
    }

    private func coordinateSpan(withMapView mapView: MKMapView, centerCoordinate: CLLocationCoordinate2D, zoomLevel: UInt) ->MKCoordinateSpan {
        let centerPixelX = longitudeToPixelSpaceX(centerCoordinate.longitude)
        let centerPixelY = latitudeToPixelSpaceY(centerCoordinate.latitude)

        let zoomExponent = Double(20 - zoomLevel)
        let zoomScale = pow(2.0, zoomExponent)

        let mapSizeInPixels = mapView.bounds.size
        let scaledMapWidth =  Double(mapSizeInPixels.width) * zoomScale
        let scaledMapHeight = Double(mapSizeInPixels.height) * zoomScale

        let topLeftPixelX = centerPixelX - (scaledMapWidth / 2);
        let topLeftPixelY = centerPixelY - (scaledMapHeight / 2);

        //    // find delta between left and right longitudes
        let minLng = pixelSpaceXToLongitude(topLeftPixelX)
        let maxLng = pixelSpaceXToLongitude(topLeftPixelX + scaledMapWidth)
        let longitudeDelta = maxLng - minLng;

        let minLat = pixelSpaceYToLatitude(topLeftPixelY)
        let maxLat = pixelSpaceYToLatitude(topLeftPixelY + scaledMapHeight)
        let latitudeDelta = -1 * (maxLat - minLat);

        let span = MKCoordinateSpanMake(latitudeDelta, longitudeDelta)
        return span
    }

    func zoom(toCenterCoordinate centerCoordinate:CLLocationCoordinate2D ,zoomLevel: UInt) {
        let zoomLevel = min(zoomLevel, 20)
        let span = self.coordinateSpan(withMapView: self, centerCoordinate: centerCoordinate, zoomLevel: zoomLevel)
        let region = MKCoordinateRegionMake(centerCoordinate, span)
        self.setRegion(region, animated: true)

    }
}

Answer 4

将以下代码放在您CustomMapView的MKMapView Call子类中来自init

class CustomMapView: MKMapView {
private func zoom() {
            let dortmundLocation = CLLocation(latitude: 51.516667, longitude: 7.466667)
            let dortmunRegion = MKCoordinateRegion(center: CLLocationCoordinate2D(latitude: dortmundLocation.coordinate.latitude, longitude: dortmundLocation.coordinate.longitude), span: MKCoordinateSpan(latitudeDelta: 0.01, longitudeDelta: 0.01))
            self.setRegion(dortmunRegion, animated: true)
        }
}