How to set zoom level or radius in map view? - ios

Question

Good day. I would like to know how to set like a radius of 1km on a current location on a MapView with
mapView.showsUserLocation = true
Is that possible? Thank you.

Answer 1

You can set "zoom level" by MKCoordinateSpanMake.
Try with this:
mapView.setRegion(MKCoordinateRegion(center: CLLocationCoordinate2DMake(location.coordinate.latitude, location.coordinate.longitude), span: MKCoordinateSpanMake(0.05, 0.05)), animated: true)

Answer 2

Not my code. Maybe it can help you
extension MKMapView {
private var MERCATOR_OFFSET: Double {
get {
return 268435456
}
}
private var MERCATOR_RADIUS: Double {
get {
return 85445659.44705395
}
}
private var MAX_ZOOM_LEVEL: Double {
get {
return 19
}
}
// MARK: - Private functions
private func longitudeToPixelSpaceX (longitude: Double) -> Double {
return round(MERCATOR_OFFSET + MERCATOR_RADIUS * longitude * M_PI / 180.0)
}
private func latitudeToPixelSpaceY (latitude: Double) -> Double {
let a = 1 + sinf(Float(latitude * M_PI) / 180.0)
let b = 1.0 - sinf(Float(latitude * M_PI / 180.0)) / 2.0
return round(MERCATOR_OFFSET - MERCATOR_RADIUS * Double(logf(a / b)))
}
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 coordinateSpanWithMapView(mapView: MKMapView, centerCoordinate: CLLocationCoordinate2D, andZoomLevel zoomLevel:Int) -> MKCoordinateSpan {
// convert center coordiate to pixel space
let centerPixelX = self.longitudeToPixelSpaceX(centerCoordinate.longitude)
let centerPixelY = self.latitudeToPixelSpaceY(centerCoordinate.latitude)
// determine the scale value from the zoom level
let zoomExponent = 20 - zoomLevel
let zoomScale = CGFloat(pow(Double(2), Double(zoomExponent)))
// scale the map’s size in pixel space
let mapSizeInPixels = mapView.bounds.size
let scaledMapWidth = mapSizeInPixels.width * zoomScale
let scaledMapHeight = mapSizeInPixels.height * zoomScale
// figure out the position of the top-left pixel
let topLeftPixelX = CGFloat(centerPixelX) - (scaledMapWidth / 2)
let topLeftPixelY = CGFloat(centerPixelY) - (scaledMapHeight / 2)
// find delta between left and right longitudes
let minLng: CLLocationDegrees = self.pixelSpaceXToLongitude(Double(topLeftPixelX))
let maxLng: CLLocationDegrees = self.pixelSpaceXToLongitude(Double(topLeftPixelX + scaledMapWidth))
let longitudeDelta: CLLocationDegrees = maxLng - minLng
// find delta between top and bottom latitudes
let minLat: CLLocationDegrees = self.pixelSpaceYToLatitude(Double(topLeftPixelY))
let maxLat: CLLocationDegrees = self.pixelSpaceYToLatitude(Double(topLeftPixelY + scaledMapHeight))
let latitudeDelta: CLLocationDegrees = -1 * (maxLat - minLat)
// create and return the lat/lng span
let span = MKCoordinateSpanMake(latitudeDelta, longitudeDelta)
return span
}
// MARK: - Public Functions
func setCenterCoordinate(centerCoordinate: CLLocationCoordinate2D, zoomLevel: Int, animated: Bool) {
// clamp large numbers to 28
let zoom = min(zoomLevel, 28)
// use the zoom level to compute the region
let span = self.coordinateSpanWithMapView(self, centerCoordinate:centerCoordinate, andZoomLevel:zoom)
let region = MKCoordinateRegionMake(centerCoordinate, span)
// set the region like normal
self.setRegion(region, animated:animated)
}
func getZoomLevel() -> Int {
let longitudeDelta = self.region.span.longitudeDelta
let mapWidthInPixels = self.bounds.size.width*2 //2 is for retina display
let zoomScale = longitudeDelta * MERCATOR_RADIUS * M_PI / Double((180.0 * mapWidthInPixels))
var zoomer = MAX_ZOOM_LEVEL - log2(zoomScale)
if zoomer < 0 {
zoomer = 0
}
zoomer = round(zoomer)
return Int(zoomer)
}
}
Use like
mapView.setCenterCoordinate(mapView.centerCoordinate, zoomLevel: 17, animated: true)

Answer 3

here i am adding circle from current location to radius of 1 km and area of map displaya about 6 km square. i think it will help you.
// adding circle as overlay
func addRadiusCircle(location: CLLocation){
self.mapView.delegate = self
//radius of 1000 meters
let circle = MKCircle(centerCoordinate: location.coordinate, radius: 1000 as CLLocationDistance)
self.mapView.addOverlay(circle)
}
//circle design and coloring
func mapView(mapView: MKMapView, rendererForOverlay overlay: MKOverlay) -> MKOverlayRenderer {
let circle = MKCircleRenderer(overlay: overlay)
if overlay is MKCircle {
circle.strokeColor = UIColor.blackColor()
circle.fillColor = UIColor(red: 235/255, green: 174/255, blue: 13/255, alpha:0.3)
circle.lineWidth = 1
}
return circle
}
// initial area to display on map
func centerMapOnLocation(location: CLLocation) {
let coordinateRegion = MKCoordinateRegionMakeWithDistance(location.coordinate,
6000, 6000)
mapView.setRegion(coordinateRegion, animated: true)
}