Question

I have lots of points (40-100) that I am using to construct a polygon to place on my app’s map view. However when using this many points, the overlays refuse to display, there is no error or anything. If I switch back to using fewer numbers of points (4-8) the overlays display again. What is the reason for this and how can I bypass this issue? Thanks in advance!

EDIT 1:

Here is all the relevant code from my Map View:

Header:

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


@interface ParkingMapViewController : UIViewController <MKMapViewDelegate> {
    MKMapView *mapView;
    permitTypes permitType;
}

@property (nonatomic, retain) IBOutlet MKMapView *mapView;
@property (nonatomic) permitTypes permitType;


-(void)loadAnnotations; //helper function that loads all annotation data from plist
-(void)loadOverlays; //helper function that loads all overlay data from plist
-(void)showCurrentLocationButtonTapped:(id)sender;


@end

Implementation (stripped out some functions pertaining to annotations and callouts, as they are not relevant here):

#import "ParkingMapViewController.h"
#import "MKMapView+ZoomLevel.h"
#import "ParkingAnnotation.h"
#import "ParkingAnnotationView.h"
#import "PermitDetailViewController.h"
#import "ParkingRegionOverlay.h"
#import "CoreDataSingleton.h"


//#define UCD_LATITUDE <some lat>
//#define UCD_LONGITUDE <some long>

@implementation ParkingMapViewController

@synthesize mapView;
@synthesize permitType;

#pragma mark Custom Methods


- (void)showCurrentLocationButtonTapped:(id)sender {
    NSLog(@"Showing current location.");

    if ([mapView showsUserLocation] == NO) {
        [mapView setShowsUserLocation:YES];
    }
    [mapView setCenterCoordinate:mapView.centerCoordinate zoomLevel:13 animated:YES];

}

//...


#pragma mark Builtin Methods

/*
 // The designated initializer.  Override if you create the controller programmatically and want to perform customization that is not appropriate for viewDidLoad.
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil {
    if ((self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil])) {
        // Custom initialization
    }
    return self;
}
*/


// Implement viewDidLoad to do additional setup after loading the view, typically from a nib.
- (void)viewDidLoad {
    [super viewDidLoad];
    mapView.delegate = self;

    self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:100 
                                              target:self action:@selector(showCurrentLocationButtonTapped:)];

    [self loadOverlays];
    [self loadAnnotations];

    CLLocationCoordinate2D centerCoord = { UCD_LATITUDE, UCD_LONGITUDE };
    [mapView setCenterCoordinate:centerCoord zoomLevel:13 animated:NO]; //from "MKMapView+ZoomLevel.h"
}

- (parkingAnnotationType)annotationTypeLookup:(permitTypes)pType
{
    if (pType == permitTypeC) {
        return annotationTypeC;
    } else if (pType == permitTypeL) {
        return annotationTypeL;
    } else if (pType == permitTypeVisitor) {
        return annotationTypeVisitor;
    } else if (pType == permitTypeDisabled) {
        return annotationTypeDisabled;
    } else if (pType == permitTypeVendor) {
        return annotationTypeVendor;
    } else if (pType == permitTypeBikeCommuter) {
        return annotationTypeBikeCommuter;
    }
    return annotationTypeNone;
}

//helper function that loads all annotation data from plist
- (void)loadAnnotations{
    //retrieve path of plist file and populate relevant types with its information
    NSString *plistPath = [[NSBundle mainBundle] pathForResource:@"PermitData" ofType:@"plist"];
    NSDictionary *rootOfPermitDataPlistDict = [[NSDictionary alloc] initWithContentsOfFile:plistPath];
    if ([[self title] isEqualToString:@"All Permits"]) {
        for (id key in rootOfPermitDataPlistDict) {

            NSMutableDictionary *permitDict = [rootOfPermitDataPlistDict objectForKey:key];

            //array containing annotation information: latitude, longitude, title, subtitle(see PermitData.plist)
            NSArray *annotationsArray = [permitDict objectForKey:@"annotations"];

            CLLocationCoordinate2D workingCoordinate;
            //loop through annotations array, creating parking annotations filled with the information found in the plist
            for(NSDictionary *annotationContainerDict in annotationsArray){

                ParkingAnnotation *parkingAnnot = [[ParkingAnnotation alloc] init];
                workingCoordinate.latitude = [[annotationContainerDict objectForKey:@"latitude"] doubleValue];
                workingCoordinate.longitude = [[annotationContainerDict objectForKey:@"longitude"] doubleValue];
                [parkingAnnot setCoordinate:workingCoordinate];
                [parkingAnnot setTitle:[annotationContainerDict objectForKey:@"title"]];
                [parkingAnnot setSubtitle:[annotationContainerDict objectForKey:@"subtitle"]];
                [parkingAnnot setAnnotationType:[self annotationTypeLookup:permitType]];

                if (parkingAnnot.annotationType == permitTypeC) [parkingAnnot setAnnotationType:annotationTypeC];
                else if (parkingAnnot.annotationType == permitTypeL) [parkingAnnot setAnnotationType:annotationTypeL];
                else if (parkingAnnot.annotationType == permitTypeVisitor) [parkingAnnot setAnnotationType:annotationTypeVisitor];
                else if (parkingAnnot.annotationType == permitTypeDisabled) [parkingAnnot setAnnotationType:annotationTypeDisabled];
                else if (parkingAnnot.annotationType == permitTypeVendor) [parkingAnnot setAnnotationType:annotationTypeVendor];
                else if (parkingAnnot.annotationType == permitTypeBikeCommuter) [parkingAnnot setAnnotationType:annotationTypeBikeCommuter];

                [mapView addAnnotation:parkingAnnot];
                [parkingAnnot release];
            }//for
        }//for
    }//if
    else {
        NSDictionary *permitDict = [[NSDictionary alloc] initWithDictionary:[rootOfPermitDataPlistDict objectForKey:[self title]]];
        //array containing annotation information: latitude, longitude, title, subtitle(see PermitData.plist)
        NSArray *annotationsArray = [[NSArray alloc] initWithArray:[permitDict objectForKey:@"annotations"]];
        [permitDict release];
        [rootOfPermitDataPlistDict release];

        CLLocationCoordinate2D workingCoordinate;
        NSDictionary *annotationContainerDict = [[NSDictionary alloc] init];
        //loop through annotations array, creating parking annotations filled with the information found in the plist
        for(annotationContainerDict in annotationsArray){

            ParkingAnnotation *parkingAnnot = [[ParkingAnnotation alloc] init];
            workingCoordinate.latitude = [[annotationContainerDict objectForKey:@"latitude"] doubleValue];
            workingCoordinate.longitude = [[annotationContainerDict objectForKey:@"longitude"] doubleValue];
            [parkingAnnot setCoordinate:workingCoordinate];
            [parkingAnnot setTitle:[annotationContainerDict objectForKey:@"title"]];
            [parkingAnnot setSubtitle:[annotationContainerDict objectForKey:@"subtitle"]];

            if (permitType == permitTypeC) [parkingAnnot setAnnotationType:annotationTypeC];
            else if (permitType == permitTypeL) [parkingAnnot setAnnotationType:annotationTypeL];
            else if (permitType == permitTypeVisitor) [parkingAnnot setAnnotationType:annotationTypeVisitor];
            else if (permitType == permitTypeDisabled) [parkingAnnot setAnnotationType:annotationTypeDisabled];
            else if (permitType == permitTypeVendor) [parkingAnnot setAnnotationType:annotationTypeVendor];
            else if (permitType == permitTypeBikeCommuter) [parkingAnnot setAnnotationType:annotationTypeBikeCommuter];

            [mapView addAnnotation:parkingAnnot];
            [parkingAnnot release];
        }//for

        [annotationContainerDict release];
        [annotationsArray release];
    }//else
}//loadAnnotations


//helper function that loads all overlay data from Core Data and adds it to map view
-(void)loadOverlays{

    NSError *error;
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    CoreDataSingleton *coreDataSingleton = [CoreDataSingleton sharedManager];
    NSEntityDescription *entity = [NSEntityDescription 
                                   entityForName:@"ParkingLot" inManagedObjectContext:[coreDataSingleton managedObjectContext]];
    [fetchRequest setEntity:entity];
    NSArray *fetchedObjects = [[coreDataSingleton managedObjectContext] executeFetchRequest:fetchRequest error:&error];
    for (NSManagedObject *info in fetchedObjects) {
        NSArray *pointsArray = [NSArray arrayWithArray:[info valueForKey:@"coordPoints"]];
        ParkingRegionOverlay *regionPolygon = [[ParkingRegionOverlay alloc] initWithPoints:pointsArray andTitle:[info valueForKey:@"lotId"]];
        [mapView addOverlay:regionPolygon];
    }        
    [fetchRequest release];

}//loadOverlays


//...


//customizes overlay view
- (MKOverlayView *)mapView:(MKMapView *)mapView 
            viewForOverlay:(id <MKOverlay>)overlay
{   
    if ([overlay isKindOfClass:[ParkingRegionOverlay class]])
    {
        //get the MKPolygon inside the ParkingRegionOverlay...
        MKPolygon *proPolygon = ((ParkingRegionOverlay*)overlay).polygon;

        MKPolygonView *aView = [[[MKPolygonView alloc] 
                                 initWithPolygon:proPolygon] autorelease];

        aView.fillColor = [[UIColor cyanColor] colorWithAlphaComponent:0.7];
        aView.strokeColor = [[UIColor blueColor] colorWithAlphaComponent:0.7];
        aView.lineWidth = 3;

        return aView;
    }
    return nil;
}




/*
// Override to allow orientations other than the default portrait orientation.
- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
    // Return YES for supported orientations
    return (interfaceOrientation == UIInterfaceOrientationPortrait);
}
*/

- (void)didReceiveMemoryWarning {
    // Releases the view if it doesn't have a superview.
    [super didReceiveMemoryWarning];

    // Release any cached data, images, etc that aren't in use.
}

- (void)viewDidUnload {
    [super viewDidUnload];
    //[mapView setShowsUserLocation:NO];
    // Release any retained subviews of the main view.
    // e.g. self.myOutlet = nil;
}


- (void)dealloc {
    [mapView release];
    [super dealloc];
}


@end

It may be a memory issue within the loadOverlays function… however all the console output is just as it should be, but with more coordinates printed out, and the app never crashes due to too many objects being allocated or anything. Thanks!

Answer 1

Please consult the answer marked as the answer in this post: Loading Annotations to Map View From Plist Not Working