Getting other users within range

gistfile1.m

 for (NSUInteger i = 1; i < myZapCards.count; i++) {
            [cardsToQuery addObject:[myZapCards objectAtIndex:i]];
        }
        PFQuery *getUsers = [PFQuery queryWithClassName:@"cardLocation"];
        // Interested in locations near user.
        [getUsers whereKey:@"location" nearGeoPoint:point withinMiles:10];
        [getUsers findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
            if (!error) {
                resultSet = [[NSMutableArray alloc]initWithCapacity:1];
                NSLog(@"Successfully retrieved %d record.", objects.count);
                for (PFObject *card in objects) {
                    PFObject *cards = [card objectForKey:@"card"];
                    PFObject *currentUser = [[PFUser currentUser]objectForKey:@"username"];
                    PFObject *userID = [[[card objectForKey:@"card"] objectForKey:@"cardOwner"] objectForKey:@"username"];
                    NSString *currentUserNameString = [NSString stringWithFormat:@"%@", currentUser];
                    NSString *fetchedUserNameString = [NSString stringWithFormat:@"%@", userID];
                    if ([card objectForKey:@"card"] != nil) {
                        //only get cards if they are currently set to broadcasting
                        if ([[[card objectForKey:@"card"]objectForKey:@"active"]isEqualToString:@"1"]) {
                            if ([[[card objectForKey:@"card"]objectForKey:@"broadcasting"]isEqualToString:@"1"]) {
                                if (![currentUserNameString isEqualToString:fetchedUserNameString]) {
                                    NSTimeInterval timeSinceLastUpdate = [card.updatedAt timeIntervalSinceNow];
                                    //only display users if they've checked in less than 30 minutes ago
                                    if (timeSinceLastUpdate > -1800) {
                                        [resultSet addObject:cards];
                                    }
                                }
                            }
                        }
                    }
                }