无法绘制MKPolylineView横经度+/- 180

我在MKMapView上绘制MKPolylineView时遇到问题。 这条线代表了环球旅行，它始于纽约附近，始终向东行进。 这次旅行的一站，从日本到旧金山，穿越太平洋，因此经度+/- 180。 MKPolylineView确实连接了这两个点，但它的行进方向错误。 也就是说，这条线路从日本西部返回旧金山，而不是向东穿过太平洋。 我没有看到任何选项让我指定线段应该连接两个点的方向。

简而言之，MKMapView似乎并不了解世界是圆的。 有没有办法按照预期画线，从日本东行到旧金山？

我有一个截图，清楚地显示问题：
Polyline http://sofzh.miximages.com/ios/MKPolylineView.png

Answer 1

这似乎是MKMapView的限制。

解决方法是将+/- 180交叉分成“东”和“西”部分。

对于环球旅行（完成==开始），您可以将交叉点的“西”部分放在折线的前面。
例如：

CLLocationCoordinate2D newYorkCoord = CLLocationCoordinate2DMake(40.7141667, -74.0063889); CLLocationCoordinate2D londonCoord = CLLocationCoordinate2DMake(51.5, -0.116667); CLLocationCoordinate2D japanCoord = CLLocationCoordinate2DMake(36, 138); CLLocationCoordinate2D sanFranciscoCoord = CLLocationCoordinate2DMake(37.775, -122.4183333); CLLocationCoordinate2D japanToSFMidpointEast; //use average calc as crude way to find midpoint... japanToSFMidpointEast.latitude = (japanCoord.latitude + sanFranciscoCoord.latitude)/2.0; japanToSFMidpointEast.longitude = 180; CLLocationCoordinate2D japanToSFMidpointWest; japanToSFMidpointWest.latitude = japanToSFMidpointEast.latitude; japanToSFMidpointWest.longitude = -180; int pointsCount = 6; CLLocationCoordinate2D *points = malloc(pointsCount * sizeof(CLLocationCoordinate2D)); points[0] = japanToSFMidpointWest; points[1] = sanFranciscoCoord; points[2] = newYorkCoord; points[3] = londonCoord; points[4] = japanCoord; points[5] = japanToSFMidpointEast; MKPolyline *polyline = [MKPolyline polylineWithCoordinates:points count:pointsCount]; [mapView addOverlay:polyline]; free(points); points = NULL; 

如果旅行不在世界各地（完成！=开始），您将不得不使用两条折线。
这个例子从日本到SF：

 CLLocationCoordinate2D japanCoord = CLLocationCoordinate2DMake(36, 138); CLLocationCoordinate2D sanFranciscoCoord = CLLocationCoordinate2DMake(37.775, -122.4183333); CLLocationCoordinate2D japanToSFMidpointEast; japanToSFMidpointEast.latitude = (japanCoord.latitude + sanFranciscoCoord.latitude)/2.0; japanToSFMidpointEast.longitude = 180; CLLocationCoordinate2D japanToSFMidpointWest; japanToSFMidpointWest.latitude = japanToSFMidpointEast.latitude; japanToSFMidpointWest.longitude = -180; int eastPointsCount = 2; CLLocationCoordinate2D *eastPoints = malloc(eastPointsCount * sizeof(CLLocationCoordinate2D)); eastPoints[0] = japanCoord; eastPoints[1] = japanToSFMidpointEast; MKPolyline *eastPolyline = [MKPolyline polylineWithCoordinates:eastPoints count:eastPointsCount]; [mapView addOverlay:eastPolyline]; free(eastPoints); eastPoints = NULL; int westPointsCount = 2; CLLocationCoordinate2D *westPoints = malloc(westPointsCount * sizeof(CLLocationCoordinate2D)); westPoints[0] = japanToSFMidpointWest; westPoints[1] = sanFranciscoCoord; MKPolyline *westPolyline = [MKPolyline polylineWithCoordinates:westPoints count:westPointsCount]; [mapView addOverlay:westPolyline]; free(westPoints); westPoints = NULL;