检测点是否在MKPolygon覆盖范围内

Question

我希望能够判断tap是否在MKPolygon中。

我有一个MKPolygon：

CLLocationCoordinate2D  points[4];

points[0] = CLLocationCoordinate2DMake(41.000512, -109.050116);
points[1] = CLLocationCoordinate2DMake(41.002371, -102.052066);
points[2] = CLLocationCoordinate2DMake(36.993076, -102.041981);
points[3] = CLLocationCoordinate2DMake(36.99892, -109.045267);

MKPolygon* poly = [MKPolygon polygonWithCoordinates:points count:4];

[self.mapView addOverlay:poly];  

//create UIGestureRecognizer to detect a tap
UITapGestureRecognizer *tapRecognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(foundTap:)];
tapRecognizer.numberOfTapsRequired = 1;
tapRecognizer.numberOfTouchesRequired = 1;
[self.mapView addGestureRecognizer:tapRecognizer];

它只是科罗拉多州的基本轮廓。

我点击了lat / long转换设置：

-(IBAction)foundTap:(UITapGestureRecognizer *)recognizer
{
    CGPoint point = [recognizer locationInView:self.mapView];

    CLLocationCoordinate2D tapPoint = [self.mapView convertPoint:point toCoordinateFromView:self.view];
}

但如果我的分接点在MKPolygon内，我不确定如何技术。似乎没有办法做这个检查，所以我猜我需要将MKPolygon转换为CGRect并使用CGRectContainsPoint。

MKPolygon有一个.points属性，但我似乎无法让它们退出。

有什么建议吗？

编辑：

以下两种解决方案均适用于iOS 6或更低版本，但在iOS 7中有效。在iOS 7中，polygon.path属性始终返回NULL。安娜女士非常友好地提供a solution in another SO question here。它涉及从多边形点创建自己的路径以传递到CGPathContainsPoint()。

我的多边形图像：

Answer 1

我创建了这个MKPolygon类别，以防有人想要使用它。似乎运作良好。您必须考虑内部多边形（即多边形中的孔）：

@interface MKPolygon (PointInPolygon)
  -(BOOL) pointInPolygon:(CLLocationCoordinate2D) point mapView: (MKMapView*) mapView;
@end

@implementation MKPolygon (PointInPolygon)

-(BOOL) pointInPolygon:(CLLocationCoordinate2D) point mapView: (MKMapView*) mapView {
    MKMapPoint mapPoint = MKMapPointForCoordinate(point);
    MKPolygonView * polygonView = (MKPolygonView*)[mapView viewForOverlay:self];
    CGPoint polygonViewPoint = [polygonView pointForMapPoint:mapPoint];
    return CGPathContainsPoint(polygonView.path, NULL, polygonViewPoint, NO) && 
        ![self pointInInteriorPolygons:point mapView:mapView];
}

-(BOOL) pointInInteriorPolygons:(CLLocationCoordinate2D) point mapView: (MKMapView*) mapView {
    return [self pointInInteriorPolygonIndex:0 point:point mapView:mapView];
}

-(BOOL) pointInInteriorPolygonIndex:(int) index point:(CLLocationCoordinate2D) point mapView: (MKMapView*) mapView {
    if(index >= [self.interiorPolygons count])
        return NO;
    return [[self.interiorPolygons objectAtIndex:index] pointInPolygon:point mapView:mapView] || [self pointInInteriorPolygonIndex:(index+1) point:point mapView:mapView];
}

@end

Answer 2

您的foundTap方法：

-(IBAction)foundTap:(UITapGestureRecognizer *)recognizer
{
    CGPoint point = [recognizer locationInView:self.mapView];

    CLLocationCoordinate2D tapPoint = [self.mapView convertPoint:point toCoordinateFromView:self.view];

    [self pointInsideOverlay:tapPoint];

    if (isInside) 
     {
       ....
     }
}

这是一种从前一个方法调用以检查该点是否在叠加层内的方法：

-(void)pointInsideOverlay:(CLLocationCoordinate2D )tapPoint 
{
    isInside = FALSE; 

    MKPolygonView *polygonView = (MKPolygonView *)[mapView viewForOverlay:polygonOverlay];

    MKMapPoint mapPoint = MKMapPointForCoordinate(tapPoint);

    CGPoint polygonViewPoint = [polygonView pointForMapPoint:mapPoint];

    BOOL mapCoordinateIsInPolygon = CGPathContainsPoint(polygonView.path, NULL, polygonViewPoint, NO);

        if ( !mapCoordinateIsInPolygon )

            //we are finding points that are inside the overlay
        {
            isInside = TRUE;
        }
}

Answer 3

我从字符串中的xml文件中获取MKPolygon数据点。我将数据字符串解析为数组，并使用http://alienryderflex.com/polygon/

中的方法

它对我有用....

-(BOOL)isPoint:(CLLocationCoordinate2D)findLocation inPloygon:(NSArray*)polygon{

    NSMutableArray *tempPolygon=[NSMutableArray arrayWithArray:polygon];
    int   i, j=(int)tempPolygon.count-1 ;
    bool  oddNodes=NO;
    double x=findLocation.latitude;
    double y=findLocation.longitude;

    for (i=0; i<tempPolygon.count; i++) {
        NSString*coordString=[tempPolygon objectAtIndex:i];
        NSArray*pointsOfCoordString=[coordString componentsSeparatedByString:@","];
        CLLocationCoordinate2D point=CLLocationCoordinate2DMake([[pointsOfCoordString objectAtIndex:1] doubleValue], [[pointsOfCoordString objectAtIndex:0] doubleValue]);
        NSString*nextCoordString=[tempPolygon objectAtIndex:j];
        NSArray*nextPointsOfCoordString=[nextCoordString componentsSeparatedByString:@","];
        CLLocationCoordinate2D nextPoint=CLLocationCoordinate2DMake([[nextPointsOfCoordString objectAtIndex:1] doubleValue], [[nextPointsOfCoordString objectAtIndex:0] doubleValue]);


        if ((point.longitude<y && nextPoint.longitude>=y)
            ||  (nextPoint.longitude<y && point.longitude>=y)) {
            if (point.latitude+(y-point.longitude)/(nextPoint.longitude-point.longitude)*(nextPoint.latitude-point.latitude)<x) {
                oddNodes=!oddNodes; }}
        j=i; }


    return oddNodes;

}

我的多边形（NSArray）对象是字符串，例如@"-89.860021,44.944266,0"

Answer 4

这里是swift 3更新版本，感谢@Steve Stomp

extension MKPolygon {

    func contains(coordinate: CLLocationCoordinate2D) -> Bool {

        let polygonRenderer = MKPolygonRenderer(polygon: self)
        let currentMapPoint: MKMapPoint = MKMapPointForCoordinate(coordinate)
        let polygonViewPoint: CGPoint = polygonRenderer.point(for: currentMapPoint)

        return  polygonRenderer.path.contains(polygonViewPoint)
    }
}

Answer 5

确定一个点是否在任意多边形中是非常重要的，并且Apple不提供它作为MKPolygon的一部分也就不足为奇了。您可以访问这些点，这样您就可以迭代边缘。

要确定点p是否在多边形s内，请将每个边视为s中的有向线段。如果来自p的光线在任何固定方向上（通常与X轴或Y轴平行）与线段相交，则将光线的叉积的Z分量的符号与该有向线段截取。如果Z分量> 0，将1添加到计数器。如果是＆lt;实现这一点的技巧是避免边缘几乎与光线平行时出现问题，或者当光线通过一个顶点时（它必须只计数一次，而不是每个边缘计数一次）。

当您对s中的所有边缘执行此操作时，您将计算光线与多边形轮廓相交的次数，如果边缘从左向右移动，则添加，如果它是从从右到左，你减去了。如果结果总和为零，则您位于多边形之外。否则你就在里面。

有许多可能的优化。其中之一是在更完整的测试之前进行快速边界框测试。另一种方法是在所有边上都有一个带有边界的数据结构，以便轻易地丢弃不与光线相交的边。

编辑：A X B的Z分量（A与B的叉积）由下式给出：

a.x * b.y - a.y * b.x

因为你所关心的只是标志，你可以检查

a.x * b.y > a.y * b.x

Answer 6

这在Swift中对我有用：

extension MKPolygon {

    func isCoordinateInsidePolyon(coordinate: CLLocationCoordinate2D) -> Bool {

        var inside = false

        let polygonRenderer = MKPolygonRenderer(polygon: self)
        let currentMapPoint: MKMapPoint = MKMapPointForCoordinate(coordinate)
        let polygonViewPoint: CGPoint = polygonRenderer.pointForMapPoint(currentMapPoint)

        if CGPathContainsPoint(polygonRenderer.path, nil, polygonViewPoint, true) {
            inside = true
        }

        return inside
    }
}