How to determine if an annotation is inside of MKPolygonView (iOS)

ios mkmapview mkpolygonview
Mat picture Mat · Dec 4, 2010 · Viewed 8.9k times · Source

I'm trying to calculate if a specific annotation(like the blue circle of the user location) or a MKPinAnnotation is inside an MKPolygon layer on the mapview.

Any advice to achieve this?

Answer

user467105 picture user467105 · Dec 4, 2010

The following converts the coordinate to a CGPoint in the polygon view and uses CGPathContainsPoint to test if that point is in the path (which may be non-rectangular):

CLLocationCoordinate2D mapCoordinate = ...; //user location or annot coord

MKMapPoint mapPoint = MKMapPointForCoordinate(mapCoordinate);

MKPolygonView *polygonView = 
    (MKPolygonView *)[mapView viewForOverlay:polygonOverlay];

CGPoint polygonViewPoint = [polygonView pointForMapPoint:mapPoint];

BOOL mapCoordinateIsInPolygon = 
    CGPathContainsPoint(polygonView.path, NULL, polygonViewPoint, NO);

This should work with any overlay view that is a subclass of MKOverlayPathView. You can actually replace MKPolygonView with MKOverlayPathView in the example.

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