iphone - Obteniendo los límites de un MKMapView

cocoa-touch mapkit

Question

Para configurar una consulta a un servidor externo, quiero obtener los límites de la vista de mapa actual en una aplicación de iPhone que estoy construyendo. UIView debe responder a los límites, pero parece que MKMapView no lo hace. Después de establecer una región y hacer zoom en el mapa, intento obtener los límites. Estoy atascado en el primer paso, que es tratar de obtener los CGPoints que representan las esquinas SE y NW del mapa. Después de eso, iba a usar:

- (CLLocationCoordinate2D)convertPoint:(CGPoint)point toCoordinateFromView:(UIView *)view

Para transformar los puntos en coordenadas del mapa. Pero ni siquiera puedo llegar tan lejos ...

//Recenter and zoom map in on search location
MKCoordinateRegion region =  {{0.0f, 0.0f}, {0.0f, 0.0f}};
region.center = mySearchLocation.searchLocation.coordinate;
region.span.longitudeDelta = 0.01f;
region.span.latitudeDelta = 0.01f;
[self.mapView setRegion:region animated:YES];


//After the new search location has been added to the map, and the map zoomed, we need to update the search bounds
//First we need to calculate the corners of the map
CGPoint se = CGPointMake(self.mapView.bounds.origin.x, mapView.bounds.origin.y);
CGPoint nw = CGPointMake((self.mapView.bounds.origin.x + mapView.bounds.size.width), (mapView.bounds.origin.y + mapView.bounds.size.height));
NSLog(@"points are: se %@, nw %@", se, nw);

El código se compila sin advertencias, sin embargo, se y nw son ambos nulos. Al mirar a self.mapView.bounds.origin.x, la variable es 0. Intentar con NSLog directamente self.mapView.bounds.size.width me da una "Señal de programa recibida:" EXC_BAD_ACCESS "." que parece provenir de NSLog.

¿Alguien sabe la forma correcta de obtener la esquina sureste y la esquina noroeste (en las coordenadas del mapa) desde el área visible de un MKMapView?

EDITAR: Parece que siempre que preguntas algo aquí la respuesta viene a ti justo después. Estaba usando% @ en lugar de @f para imprimir cada variable en NSLog que estaba arrojando errores allí. También descubrí la propiedad annotationVisibleRect de MKMapview. Sin embargo, parece que el annotationVisibleRect se basa en las coordenadas de vista principal.

Answer 1

De acuerdo, oficialmente respondí mi propia pregunta, pero como no la encontré antes publicaré la respuesta aquí:

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

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

CLLocationCoordinate2D swCoord;
swCoord = [mapView convertPoint:swPoint toCoordinateFromView:mapView];

Answer 2

Este http://wiki.openstreetmap.org/wiki/Bounding_Box es un documento para el cuadro delimitador

bbox = left,bottom,right,top
bbox = min Longitude , min Latitude , max Longitude , max Latitude

Puede tener una estructura BoundingBox que represente esto

struct BoundingBox {
  let min: CLLocationCoordinate2D
  let max: CLLocationCoordinate2D

  init(rect: MKMapRect) {
    let bottomLeft = MKMapPointMake(rect.origin.x, MKMapRectGetMaxY(rect))
    let topRight = MKMapPointMake(MKMapRectGetMaxX(rect), rect.origin.y)

    min = MKCoordinateForMapPoint(bottomLeft)
    max = MKCoordinateForMapPoint(topRight)
  }

  var points: [CLLocationDegrees] {
    return [
      min.latitude,
      min.longitude,
      max.latitude
      max.longitude,
    ]
  }
}

El visibleMapRect es el mismo que region.span

let mapView = MKMapView(frame: CGRect(x: 0, y: 0, width: 320, height: 640))
XCTAssertEqual(mapView.userLocation.coordinate.latitude, 0)
XCTAssertEqual(mapView.userLocation.coordinate.longitude, 0)

let boundingBox = BoundingBox(rect: mapView.visibleMapRect)
XCTAssertEqual(boundingBox.max.longitude-boundingBox.min.longitude, mapView.region.span.longitudeDelta)
XCTAssertEqual(boundingBox.max.latitude-boundingBox.min.latitude, mapView.region.span.latitudeDelta)

Answer 3

Este código funciona con un mapa que gira como 90/180 grados. establecer mapView.pitchEnabled = NO; por menos errores.

CLLocationDirection heading = mapView.camera.heading;

float mapWidth = mapView.frame.size.width;
float mapHeight = mapView.frame.size.height;

float neX = mapWidth;
float neY = 0.0;

float swX = 0.0;
float swY = mapHeight;


if (heading >= 0 && heading <= 90) {
    //println("Q1")
    float ratio = heading / 90;

    neX = (1-ratio) * mapWidth;
    swX = (mapWidth*ratio);
} else if (heading >= 90 && heading <= 180) {
    //println("Q2")
    float ratio = (heading - 90) / 90;
    neX = 0;
    neY = (mapHeight*ratio);
    swY = (1-ratio) * mapHeight;
    swX = mapWidth;

} else if (heading >= 180 && heading <= 270) {
    //println("Q3")
    float ratio = (heading - 180) / 90;
    neX = mapWidth*ratio;
    neY = mapHeight;
    swX = (1-ratio) * mapWidth;
    swY = 0;

} else if (heading >= 270 && heading <= 360) {
    //println("Q4");
    float ratio = (heading - 270) / 90;
    neX = mapWidth;
    neY = (1-ratio) * mapHeight;
    swY = ratio * mapHeight;

}

CGPoint swPoint = CGPointMake(swX, swY);
CGPoint nePoint = CGPointMake(neX, neY);

CLLocationCoordinate2D swCoord = [mapView convertPoint:swPoint toCoordinateFromView:mapView];
CLLocationCoordinate2D neCoord = [mapView convertPoint:nePoint toCoordinateFromView:mapView];

Answer 4

Otra opción es usar la propiedad visibleMapRect en su instancia de MKMapView y usar MKCoordinateForMapPoint () para convertir a lat / lon.

MKMapRect mRect = self.mapView.visibleMapRect;
MKMapPoint neMapPoint = MKMapPointMake(MKMapRectGetMaxX(mRect), mRect.origin.y);
MKMapPoint swMapPoint = MKMapPointMake(mRect.origin.x, MKMapRectGetMaxY(mRect));
CLLocationCoordinate2D neCoord = MKCoordinateForMapPoint(neMapPoint);
CLLocationCoordinate2D swCoord = MKCoordinateForMapPoint(swMapPoint);

Answer 5

Pude hacer que esto funcionara con la consulta de Parse GeoBox:

//Calculate the corners of the map to get the points
CGPoint nePoint = CGPointMake(self.mapView.bounds.origin.x + self.mapView.bounds.size.width, self.mapView.bounds.origin.y);
CGPoint swPoint = CGPointMake((self.mapView.bounds.origin.x),(self.mapView.bounds.origin.y+ self.mapView.bounds.size.height));

//Transform points into lat/long values
CLLocationCoordinate2D NECoordinate = [self.mapView convertPoint:nePoint toCoordinateFromView:self.mapView];
CLLocationCoordinate2D SWCoordinate = [self.mapView convertPoint:swPoint toCoordinateFromView:self.mapView];

//Convert to Parse GeoPoints
PFGeoPoint *Southwest = [PFGeoPoint geoPointWithLatitude:SWCoordinate.latitude longitude:SWCoordinate.longitude];
PFGeoPoint *Northeast = [PFGeoPoint geoPointWithLatitude:NECoordinate.latitude longitude:NECoordinate.longitude];

Answer 6

Swift away ... (Basado en la respuesta de @ deadroxy ...)

typealias Edges = (ne: CLLocationCoordinate2D, sw: CLLocationCoordinate2D)

extension MKMapView {
    func edgePoints() -> Edges {
        let nePoint = CGPoint(x: self.bounds.maxX, y: self.bounds.origin.y)
        let swPoint = CGPoint(x: self.bounds.minX, y: self.bounds.maxY)
        let neCoord = self.convertPoint(nePoint, toCoordinateFromView: self)
        let swCoord = self.convertPoint(swPoint, toCoordinateFromView: self)
        return (ne: neCoord, sw: swCoord)
    }
}

Answer 7

este sitio web resuelve el problema. http://www.softwarepassion.com/how-to-get-geographic-coordinates-of-the-visible-mkmapview-area-in-ios/

MKMapRect mRect = self.mapView.visibleMapRect;

-(CLLocationCoordinate2D)getNECoordinate:(MKMapRect)mRect{
    return [self getCoordinateFromMapRectanglePoint:MKMapRectGetMaxX(mRect) y:mRect.origin.y];
}
-(CLLocationCoordinate2D)getNWCoordinate:(MKMapRect)mRect{
    return [self getCoordinateFromMapRectanglePoint:MKMapRectGetMinX(mRect) y:mRect.origin.y];
}
-(CLLocationCoordinate2D)getSECoordinate:(MKMapRect)mRect{
    return [self getCoordinateFromMapRectanglePoint:MKMapRectGetMaxX(mRect) y:MKMapRectGetMaxY(mRect)];
}
-(CLLocationCoordinate2D)getSWCoordinate:(MKMapRect)mRect{
    return [self getCoordinateFromMapRectanglePoint:mRect.origin.x y:MKMapRectGetMaxY(mRect)];
}

-(CLLocationCoordinate2D)getCoordinateFromMapRectanglePoint:(double)x y:(double)y{
    MKMapPoint swMapPoint = MKMapPointMake(x, y);
    return MKCoordinateForMapPoint(swMapPoint);
}

-(NSArray *)getBoundingBox:(MKMapRect)mRect{
    CLLocationCoordinate2D bottomLeft = [self getSWCoordinate:mRect];
    CLLocationCoordinate2D topRight = [self getNECoordinate:mRect];
    return @[[NSNumber numberWithDouble:bottomLeft.latitude ],
             [NSNumber numberWithDouble:bottomLeft.longitude],
             [NSNumber numberWithDouble:topRight.latitude],
             [NSNumber numberWithDouble:topRight.longitude]];
}