限制MKMapView显示的区域

-(void)mapView:(MKMapView *)mapView regionDidChangeAnimated:(BOOL)animated
{

//限制map显示区域
/*
newLocCoordinate : 初始的中心点经纬度
oriSpan ：初始的Span

*/
MKCoordinateRegion regin = mapView.region;

if ((regin.span.latitudeDelta > oriSpan.latitudeDelta ) || (regin.span.longitudeDelta > oriSpan.longitudeDelta) ) {

CLLocationCoordinate2D centerCoord = newLocCoordinate;

MKCoordinateSpan span = oriSpan;

MKCoordinateRegion region = MKCoordinateRegionMake(centerCoord, span);

[mapView setRegion: region animated: YES];
}

if (regin.center.latitude+regin.span.latitudeDelta/2 > newLocCoordinate.latitude+oriSpan.latitudeDelta/2
||regin.center.latitude-regin.span.latitudeDelta/2 < newLocCoordinate.latitude-oriSpan.latitudeDelta/2) {
CLLocationCoordinate2D centerCoord = newLocCoordinate;

MKCoordinateSpan span = oriSpan;

MKCoordinateRegion region = MKCoordinateRegionMake(centerCoord, span);

[mapView setRegion: region animated: YES];

}

if (regin.center.longitude+regin.span.longitudeDelta/2 > newLocCoordinate.longitude+oriSpan.longitudeDelta/2
||regin.center.longitude-regin.span.longitudeDelta/2 < newLocCoordinate.longitude-oriSpan.longitudeDelta/2) {
CLLocationCoordinate2D centerCoord = newLocCoordinate;

MKCoordinateSpan  span = oriSpan;

MKCoordinateRegion region = MKCoordinateRegionMake(centerCoord, span);

[mapView setRegion: region animated: YES];
}
}