How can I limit the map area to only one country in iOS?

Question

I am making an iOS app using mapkit. I want to limit the borders of the map only to a specific region / country. Is there any way to do this?

Answer 1

There is no way to tell the map not to scroll a specific area. The only way I could think of is to stop the user from scrolling when you click on one of your fences. The example below is written without testing or compilation at all, so you may need to tweak it yourself, but I hope it launches you.

ViewController.h

CLLocationCoordinate2D myNorthEast, mySouthWest; 

ViewController.m

 -(void)viewDidLoad{ myNorthEast = CLLocationCoordinate2DMake(lat1,lon1); mySouthWest = CLLocationCoordinate2DMake(lat2,lon2); [super viewDidLoad]; } -(void)mapView:(MKMapView *)mapView regionWillChangeAnimated:(BOOL)animated{ /* / Check if the map region is going to change outside your fence. / If so, programmatically set it back to the edge of your fence. */ if(!animated){ return; // Don't want to get stuck in a loop after you set your region below. } MKCoordinateRegion region = [mapView region]; // You will need to get the NE and SW points of the new region to compare // First we need to calculate the corners of the map so we get the points CGPoint nePoint = CGPointMake(mapView.bounds.origin.x + mapView.bounds.size.width, mapView.bounds.origin.y); CGPoint swPoint = CGPointMake(mapView.bounds.origin.x, bounds.origin.y + mapView.bounds.size.height); // Then transform those point into lat,lng values CLLocationCoordinate2D neCoord; neCoord = [mapView convertPoint:nePoint toCoordinateFromView:mapView]; CLLocationCoordinate2D swCoord; swCoord = [mapView convertPoint:swPoint toCoordinateFromView:mapView]; /* You will need to mess around with the lat/lon & sign of the new center calculation for the other cases. */ if(neCoord.latitude > myNorthEast.latitude){ MKCoordinateRegion newRegion; newRegion.span = region.span; CLLocationCoordinate2D newCenter; newCenter.longitude = region.center.longitude; newCenter.latitude = myNorthEast.latitude - region.span.latitudeDelta; newRegion.center = newCenter; [mapView setRegion:newRegion animated:NO]; }else if(neCoord.longitude < myNorthEast.longitude){ }else if(swCoord.latitude < mySouthWest.latitude){ }else if(swCoord.longitude > mySouthWest.longitude){ } } 

Part of this comes from this answer: Getting MKMapvIew bounds

Answer 2

Below is an additional specification of the previous answer. Please note that this will be different for different parts of the world:

  if(neCoord.latitude > myNorthEast.latitude){ MKCoordinateRegion newRegion; newRegion.span = region.span; CLLocationCoordinate2D newCenter; newCenter.longitude = region.center.longitude; newCenter.latitude = myNorthEast.latitude - region.span.latitudeDelta / 2; newRegion.center = newCenter; [mapView setRegion:newRegion animated:NO]; } else if(swCoord.latitude < mySouthWest.latitude){ MKCoordinateRegion newRegion; newRegion.span = region.span; CLLocationCoordinate2D newCenter; newCenter.longitude = region.center.longitude; newCenter.latitude = mySouthWest.latitude + region.span.latitudeDelta / 2; newRegion.center = newCenter; [mapView setRegion:newRegion animated:NO]; } else if(neCoord.longitude > myNorthEast.longitude){ MKCoordinateRegion newRegion; newRegion.span = region.span; CLLocationCoordinate2D newCenter; newCenter.longitude = myNorthEast.longitude - region.span.longitudeDelta / 2; newCenter.latitude = region.center.latitude; newRegion.center = newCenter; [mapView setRegion:newRegion animated:NO]; } else if(swCoord.longitude < mySouthWest.longitude){ MKCoordinateRegion newRegion; newRegion.span = region.span; CLLocationCoordinate2D newCenter; newCenter.longitude = mySouthWest.longitude + region.span.longitudeDelta / 2; newCenter.latitude = region.center.latitude; newRegion.center = newCenter; [mapView setRegion:newRegion animated:NO]; }