automatic center map

CenterMap.m

- (void)centerMap {
	
	NSArray *coordinates = [self.mapView valueForKeyPath:@"annotations.coordinate"];
	
	
	
	CLLocationCoordinate2D maxCoord = {-90.0f, -180.0f};
	
	CLLocationCoordinate2D minCoord = {90.0f, 180.0f};
	
	
	
	for(NSValue *value in coordinates) {
		
		CLLocationCoordinate2D coord = {0.0f, 0.0f};
		
		[value getValue:&coord];
		
		if(coord.longitude > maxCoord.longitude) {
			
			maxCoord.longitude = coord.longitude;
			
		}
		
		if(coord.latitude > maxCoord.latitude) {
			
			maxCoord.latitude = coord.latitude;
			
		}
		
		if(coord.longitude < minCoord.longitude) {
			
			minCoord.longitude = coord.longitude;
			
		}
		
		if(coord.latitude < minCoord.latitude) {
			
			minCoord.latitude = coord.latitude;
			
		}
		
	}
	
	MKCoordinateRegion region = {{0.0f, 0.0f}, {0.0f, 0.0f}};
	
	region.center.longitude = (minCoord.longitude + maxCoord.longitude) / 2.0;
	
	region.center.latitude = (minCoord.latitude + maxCoord.latitude) / 2.0;
	
	region.span.longitudeDelta = maxCoord.longitude - minCoord.longitude;
	
	region.span.latitudeDelta = maxCoord.latitude - minCoord.latitude;
	
	[self.mapView setRegion:region animated:YES];  
	
}