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Adding random MKnnotations around the current location in MKMapView

I have MKMapViewone that shows the current location of users. When I click the button on the navigation bar, I want to accidentally reset 10 MKAnnotationcontacts. They can be deleted anywhere, in random order, but only within the current visible area of ​​the map and around the current location.

How could something like this be done? Is there a way to have a long / lat range that is around the users location but inside the map area? Then could I randomly choose from this range?

Basically, I need to find which coordinates are available in the current MKCoordinateRegion.

Is there a better way to do this?

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4 answers

You can get your annotations using the distance between the user's location and another location.

check below code

#define DISTANCE_RADIUS     10.0    // in KM
-(NSArray *)findNearMe:(NSArray *)lounges {
NSMutableArray *arNearme = [NSMutableArray array];

CLLocation *currentLocation;
for(NSDictionary *d in lounges) 
{

currentLocation = [[CLLocation alloc] initWithLatitude:29.33891 longitude:48.077202];

    CGFloat latitude=[[d valueForKey:@"latitude"] floatValue];
    CGFloat longitude=[[d valueForKey:@"longitude"] floatValue];
    CLLocation *newPinLocation=[[CLLocation alloc] initWithLatitude:latitude longitude:longitude];
    double distanceValue=[currentLocation distanceFromLocation:newPinLocation]; 

    if(distanceValue/1000.0<=DISTANCE_RADIUS) {
        [arNearme addObject:d];
    }
}
return  arNearme;
}

It will return you an array of the range from 1 to 1000 km near the user's location. An array of annotations is used and we show your annotations to display the view with the user's location.

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I realized this is how I did it:

/**
 * Adds new pins to the map
 *
 * @version $Revision: 0.1
 */
+ (void)addPinsToMap:(MKMapView *)mapView amount:(int)howMany {

    //First we need to calculate the corners of the map so we get the points
    CGPoint nePoint = CGPointMake(mapView.bounds.origin.x + mapView.bounds.size.width, mapView.bounds.origin.y);
    CGPoint swPoint = CGPointMake((mapView.bounds.origin.x), (mapView.bounds.origin.y + mapView.bounds.size.height));

    //Then transform those point into lat,lng values
    CLLocationCoordinate2D neCoord = [mapView convertPoint:nePoint toCoordinateFromView:mapView];
    CLLocationCoordinate2D swCoord = [mapView convertPoint:swPoint toCoordinateFromView:mapView];

    // Loop
    for (int y = 0; y < howMany; y++) {
        double latRange = [MapUtility randomFloatBetween:neCoord.latitude andBig:swCoord.latitude];
        double longRange = [MapUtility randomFloatBetween:neCoord.longitude andBig:swCoord.longitude];

        // Add new waypoint to map
        CLLocationCoordinate2D location = CLLocationCoordinate2DMake(latRange, longRange);
        MPin *pin = [[MPin alloc] init];
        pin.coordinate = location;
        [mapView addAnnotation:pin];

    }//end

}//end


/**
 * Random numbers
 *
 * @version $Revision: 0.1
 */
+ (double)randomFloatBetween:(double)smallNumber andBig:(double)bigNumber {
    double diff = bigNumber - smallNumber;
    return (((double) (arc4random() % ((unsigned)RAND_MAX + 1)) / RAND_MAX) * diff) + smallNumber;
}//end
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In Swift 3.0

func addPins() {
    let nePoint = CGPoint(x: mapView.bounds.origin.x + mapView.bounds.size.width, y: mapView.bounds.origin.y)
    let sePoint = CGPoint(x: mapView.bounds.origin.x, y: mapView.bounds.origin.y + mapView.bounds.size.height)

    let neCoord = mapView.convert(nePoint, toCoordinateFrom: mapView)
    let seCoord = mapView.convert(sePoint, toCoordinateFrom: mapView)

    var y = 5
    while y > 0 {
        let latRange = randomBetweenNumbers(firstNum: Float(neCoord.latitude), secondNum: Float(seCoord.latitude))
        let longRange = randomBetweenNumbers(firstNum: Float(neCoord.longitude), secondNum: Float(seCoord.longitude))
        let location = CLLocationCoordinate2D(latitude: CLLocationDegrees(latRange), longitude: CLLocationDegrees(longRange))
        let pin = MKPointAnnotation()
        pin.coordinate = location
        pin.title = "Home"
        mapView.addAnnotation(pin)
        y -= 1
    }

}

func randomBetweenNumbers(firstNum: Float, secondNum: Float) -> Float{
    return Float(arc4random()) / Float(UINT32_MAX) * abs(firstNum - secondNum) + min(firstNum, secondNum)
}
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Swift 4:

// returned coordinates all restricted to the provided bound
// nwCoordinate: north West coordinate of the target bound
// seCoordinate: south east coordinate of the target bound

func createRandomLocation(nwCoordinate: CLLocationCoordinate2D, seCoordinate: CLLocationCoordinate2D) -> [CLLocationCoordinate2D]
{
   return (0 ... 30).enumerated().map { _ in
        let latitude = randomFloatBetween(nwCoordinate.latitude, andBig: seCoordinate.latitude)
        let longitude = randomFloatBetween(nwCoordinate.longitude, andBig: seCoordinate.longitude)
        return CLLocationCoordinate2D(latitude: latitude, longitude: longitude)
    }
}

private func randomFloatBetween(_ smallNumber: Double, andBig bigNumber: Double) -> Double {
    let diff: Double = bigNumber - smallNumber
    return ((Double(arc4random() % (UInt32(RAND_MAX) + 1)) / Double(RAND_MAX)) * diff) + smallNumber
}
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