[英]How to detect if a GPS coordinate fall in an area on MKMapView?
在我的應用程序中,我有一個圓周長的坐標數組(CLLocationCoordinate2D)。 現在我從某個地方得到一個坐標,我需要檢查新坐標是否落在圓圈內。 如果它,我只是想在該坐標上顯示一個引腳,基本上它應該屬於該區域。 我應該如何檢查這個?
謝謝,
你沒有說你的坐標數組是否只是緯度和經度, CLLocationCoordinate2D
結構或CLLocation
對象,但是如果你創建一個CLLocation
對象(如果你還沒有),你可以調用distanceFromLocation
來查看多遠它來自另一個地方。 我假設,除了周邊的坐標數組,你還有中心的坐標?
如果您有CLLocationCoordinate2D
,那么您可以這樣做:
CLLocation *location = [[CLLocation alloc] initWithLatitude:coordinate.latitude
longitude:coordinate.longitude];
CLLocation *centerLocation = [[CLLocation alloc] initWithLatitude:centerCoordinate.latitude
longitude:centerCoordinate.longitude];
CLLocationDistance distance = [location distanceFromLocation:centerLocation];
離線聊天時,聽起來地圖上的坐標數組是用戶手勢的結果(這解釋了為什么你沒有坐標圓的中心)。
鑒於這種情況,而不是使用映射方法來試圖弄清楚一個區域是否包含一個坐標,我建議使用Quartz方法來測試視圖中的CGPoint
是否包含在一個封閉的UIBezierPath
,我們將從用戶的手勢構建。
從而:
當用戶在屏幕上拖動手指時,構建UIBezierPath
;
完成后,將結果路徑與相關坐標進行比較。 例如,地圖視圖顯示用戶位置,您可以查看地圖的userLocation
屬性,使用地圖視圖的convertCoordinate:toPointToView
方法將其坐標從CLLocationCoordinate2D
轉換為視圖中的坐標視圖。
將CGPoint
放在mapview中用於用戶的當前位置,我們現在可以使用UIBezierPath
實例方法containsPoint
進行測試,以查看該點是否在UIBezierPath
路徑內。
因此,這可能看起來像:
- (void)turnOnGestureForView:(MKMapView *)mapView
{
mapView.scrollEnabled = NO;
UIPanGestureRecognizer *gesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handleGesture:)];
[mapView addGestureRecognizer:gesture];
}
- (void)turnOffGesture:(UIGestureRecognizer *)gesture map:(MKMapView *)mapView
{
[mapView removeGestureRecognizer:gesture];
mapView.scrollEnabled = YES;
}
- (void)handleGesture:(UIPanGestureRecognizer *)gesture
{
static UIBezierPath *path;
static CAShapeLayer *shapeLayer;
CGPoint location = [gesture locationInView:gesture.view];
if (gesture.state == UIGestureRecognizerStateBegan)
{
if (!shapeLayer)
{
shapeLayer = [[CAShapeLayer alloc] init];
shapeLayer.fillColor = [[UIColor clearColor] CGColor];
shapeLayer.strokeColor = [[UIColor redColor] CGColor];
shapeLayer.lineWidth = 3.0;
[self.mapView.layer addSublayer:shapeLayer];
}
path = [UIBezierPath bezierPath];
[path moveToPoint:location];
}
else if (gesture.state == UIGestureRecognizerStateChanged)
{
[path addLineToPoint:location];
shapeLayer.path = [path CGPath];
}
else if (gesture.state == UIGestureRecognizerStateEnded)
{
MKMapView *mapView = (MKMapView *)gesture.view;
[path addLineToPoint:location];
[path closePath];
CGPoint currentLocation = [mapView convertCoordinate:mapView.userLocation.coordinate
toPointToView:gesture.view];
if ([path containsPoint:currentLocation])
NSLog(@"%s path contains %@", __FUNCTION__, NSStringFromCGPoint(currentLocation));
else
NSLog(@"%s path does not contain %@", __FUNCTION__, NSStringFromCGPoint(currentLocation));
[shapeLayer removeFromSuperlayer];
shapeLayer = nil;
// if you want to turn off the gesture and turn scrolling back on, you can do that now
[self turnOffGesture:gesture map:mapView];
}
}
聲明:本站的技術帖子網頁,遵循CC BY-SA 4.0協議,如果您需要轉載,請注明本站網址或者原文地址。任何問題請咨詢:yoyou2525@163.com.