MKMapView won't add any annotations

I have an MKMapView whose delegate is set in Interface Builder and which is a retained property (hooked up in Interface Builder as well) of its view controller. Yes, I am sure they are hooked up properly. I am trying to add annotations to the mapView, but mapView: viewForAnnotation: is not called, and after adding all of the annotations with [self.map addAnnotation:annot], printing the count of the mapView's annotations array yields zero. I have no idea what is causing this because my MapPerson object implements the MKAnnotation protocol with a readonly coordinate property. Here is my code for that business...

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

@interface MapPerson : NSObject <MKAnnotation> {
  CLLocationCoordinate2D _coo;
}

@property (nonatomic, readon开发者_运维知识库ly) CLLocationCoordinate2D coordinate;

@end

And its implementation...

#import "MapPerson.h"

@implementation MapPerson

@synthesize coordinate=_coo;

- (id)init
{
    self = [super init];
    if (self) {
        // Initialization code here.
    }

    return self;
}

- (id)initWithCoordinate:(CLLocationCoordinate2D)loc {
  self = [super init];
  if (self) {
    _coo = loc;
  }
  return self;
}

I am trying to create these annotations in a delegate method from a service class which fetches coordinates from a server to the view controller containing the mapView. I have tried moving that code to a helper method which I make sure to call on the main thread, but nothing happens.

- (void)refreshMap {
  for (MapPerson *p in mapPeople) {
    [self.map addAnnotation:p];
  }
  NSLog(@"Mapview has %i annotations.", self.map.annotations.count);
  // is always 1 for the user's location
}

I have Googled and SO's and looked at several different tutorials which do not differ from my code except in names. I put a breakpoint in mapView: viewForAnnotation:, and it is only called once for the user's location annotation. The count of mapPeople is 5. Their coordinates are being set correctly. Any ideas?

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The backend is using MongoDB which had reversed latitude/longitude. Thus, the annotations were added to a location that doesn't exist on the coordinate plane of the map. I feel like an idiot for not noticing this sooner. Thanks for the answers!

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Are you not getting warnings regarding MapPerson? I believe it says in the documentation that if you want to implement MKAnnotation you need to provide a title and subtitle as well.

Can you possibly provide the code where you populate mapPeople?

EDIT: Re-read documentation, it says title and subtitle are only expected of you if you plan on creating selectable annotations.

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Have you checked if your p or people is nil?