MKPolyline не отображается в MKMapView

Вот код. Это довольно прямолинейно. Я делаю путь для того, кто идет. Итак, вот код моего файла ViewController.m:

#import "ViewController.h"

@interface ViewController ()

@property BOOL firstTime;

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view, typically from a nib.
    [self.mapView setDelegate:self];
    [self.mapView setShowsUserLocation:YES];
    [self.mapView setMapType:MKMapTypeHybrid];

    [self setLocationManager:[[CLLocationManager alloc] init]];
    [self.locationManager setDelegate:self];
    [self.locationManager setDistanceFilter:kCLDistanceFilterNone];
    [self.locationManager setDesiredAccuracy:kCLLocationAccuracyBest];
    [self.locationManager startUpdatingLocation];

    self.index = 0;

    self.firstTime = YES;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)locationManager:(CLLocationManager *)manager didUpdateLocations:(NSArray *)locations
{
    if(self.firstTime)
    {
        CLLocation *startingLocation = [locations objectAtIndex:0];
        self.startingPointCooridinates = startingLocation.coordinate;
        self.index++;

        MKPointAnnotation *startingPointAnnotation = [[MKPointAnnotation alloc] init];
        startingPointAnnotation.title = @"Starting Point";
        startingPointAnnotation.coordinate = startingLocation.coordinate;

        [self.mapView addAnnotation:startingPointAnnotation];

        self.firstTime = false;
    }

    [self.locations addObject:[locations objectAtIndex:0]];

    CLLocationCoordinate2D coordinates[[self.locations count]];
    for(int i = 0; i < self.locations.count; i++)
    {
        CLLocation *currentLocation = [locations objectAtIndex:i];
        coordinates[i] = currentLocation.coordinate;
    }

    MKPolyline *pathPolyline = [MKPolyline polylineWithCoordinates:coordinates count:self.locations.count];
    [self.mapView addOverlay:pathPolyline];
}

- (MKOverlayRenderer *)mapView:(MKMapView *)mapView rendererForOverlay:(id<MKOverlay>)overlay
{
    if([overlay isKindOfClass:[MKPolyline class]])
    {
        MKPolylineRenderer *polylineRenderer = [[MKPolylineRenderer alloc] initWithPolyline:overlay];
        polylineRenderer.fillColor = [[UIColor redColor] colorWithAlphaComponent:0.2];
        polylineRenderer.strokeColor = [[UIColor redColor] colorWithAlphaComponent:0.7];
        polylineRenderer.lineWidth = 2.0;
        return polylineRenderer;
    }
    else
    {
        return  nil;
    }
}

Теперь отображается только аннотация, а MKPolyline не отображается. Что я делаю неправильно ? Спасибо.