MKMapSnapshot category on UIImageView

UIImageView+MapSnapshot.h

//
//  UIImageView+MapSnapshot.h
//  Awning
//
//  Created by Frank Schmitt on 3/31/14.
//

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>

@interface UIImageView (MapSnapshot) <MKAnnotation>

@property (strong, nonatomic) MKMapSnapshotOptions *mapSnapshotOptions;
@property (strong, nonatomic) MKAnnotationView *annotationView;

@end

UIImageView+MapSnapshot.m

//
//  UIImageView+MapSnapshot.m
//  Awning
//
//  Created by Frank Schmitt on 3/31/14.
//

#import "UIImageView+MapSnapshot.h"
#import <objc/runtime.h>

@implementation UIImageView (MapSnapshot)
@dynamic mapSnapshotOptions;
@dynamic annotationView;

- (void)setMapSnapshotOptions:(MKMapSnapshotOptions *)options {
    objc_setAssociatedObject(self, @selector(mapSnapshotOptions), options, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
    
    [self.annotationView removeFromSuperview];

    if (options.region.span.latitudeDelta > 0.0) {
        MKMapSnapshotter *mapSnapshotter = [[MKMapSnapshotter alloc] initWithOptions:options];
        [mapSnapshotter startWithCompletionHandler:^(MKMapSnapshot *snapshot, NSError *error){
            self.image = snapshot.image;
            
            self.annotationView.bounds = CGRectMake(0.0, 0.0, self.annotationView.image.size.width, self.annotationView.image.size.height);
            
            CGPoint locationPoint = [snapshot pointForCoordinate:self.coordinate];
            self.annotationView.center = CGPointMake(locationPoint.x + self.annotationView.centerOffset.x, locationPoint.y + self.annotationView.centerOffset.y);
            [self addSubview:self.annotationView];
        }];
    }
}

- (MKMapSnapshotOptions *)mapSnapshotOptions {
    return objc_getAssociatedObject(self, @selector(mapSnapshotOptions));
}

- (CLLocationCoordinate2D)coordinate {
    return self.mapSnapshotOptions.region.center;
}

- (void)setAnnotationView:(MKAnnotationView *)annotationView {
    objc_setAssociatedObject(self, @selector(annotationView), annotationView, OBJC_ASSOCIATION_RETAIN_NONATOMIC);
}

- (MKAnnotationView *)annotationView {
    MKAnnotationView *_annotationView = objc_getAssociatedObject(self, @selector(annotationView));
    if (!_annotationView) {
        _annotationView = [[MKPinAnnotationView alloc] initWithAnnotation:self reuseIdentifier:@"Annotation"];
        [self setAnnotationView:_annotationView];
    }
    
    return _annotationView;
}

@end