[英]How to get left-top and right-bottom latitude and longitude of map in MapKit
How to get left-top and right-bottom latitude and longitude of map in MapKit? 如何在MapKit中获取地图的左上角和右下角经度? I use this code, but it doesn't work properly. 我使用此代码,但它无法正常工作。 How should I fix it? 我该如何解决?
MKCoordinateRegion region = [map region];
double topL,topG,bottomL,bottomG;
//if latitude=55 and latitudeDelta=126 topL is 118 and it will be not at top, it will be at buttom of screen
topL = region.center.latitude + region.span.latitudeDelta/2;
topG = region.center.longitude - region.span.longitudeDelta/2;
CLLocationCoordinate2D lt;
lt.latitude=topL;
lt.longitude=topG;
annotation = [Annotation new];
annotation.coordinate = lt;
annotation.title = @"Left";
[map addAnnotation:annotation];
[annotation release];
//if latitude=55 and latitudeDelta=126 bottomL is -7.23 and it will be not at bottom, it will be at above bottom of screen
bottomL = region.center.latitude - region.span.latitudeDelta/2;
bottomG = region.center.longitude + region.span.longitudeDelta/2;
CLLocationCoordinate2D rb;
rb.latitude=bottomL;
rb.longitude=bottomG;
annotation = [Annotation new];
annotation.coordinate = rb;
annotation.title = @"Right";
[map addAnnotation:annotation];
[annotation release];
There is a much easier approach to getting those coordinates... Use the points of your view, and convert: 获取这些坐标有一种更简单的方法...使用视图中的点,然后转换:
CLLocationCoordinate2D topLeft, bottomRight;
topLeft = [mapView convertPoint:CGPointMake(0, 0) toCoordinateFromView:mapView];
CGPoint pointBottomRight = CGPointMake(mapView.frame.size.width, mapView.frame.size.height);
bottomRight = [mapView convertPoint:pointBottomRight toCoordinateFromView:mapView];
I created an extension for MKMapView
我为MKMapView
创建了一个扩展
Swift 4.2 Swift 4.2
extension MKMapView {
func topLeftCoordinate() -> CLLocationCoordinate2D {
return convert(.zero, toCoordinateFrom: self)
}
func bottomRightCoordinate() -> CLLocationCoordinate2D {
return convert(CGPoint(x: frame.width, y: frame.height), toCoordinateFrom: self)
}
}
Swift 2.0 Swift 2.0
extension MKMapView {
func topLeftCoordinate() -> CLLocationCoordinate2D {
return convertPoint(CGPoint.zero, toCoordinateFromView: self)
}
func bottomRightCoordinate() -> CLLocationCoordinate2D {
return convertPoint(CGPoint(x: frame.width, y: frame.height), toCoordinateFromView: self)
}
}
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