MapKitは、実際に持っていますこれを行うMKMapViewにおける組み込み関数:
showAnnotations(annotations: [MKAnnotation], animated: Bool)
ただし、この機能は、ズームレベルのコントロールを提供していないので、私はまだ私自身の機能をしなければなりませんでした。ここで擬似コードである:それは代わりに、エッジから等距離遠い点を有するの点の平均値を中心として
zoomToAnnotations(annotations, zoomLimit) {
// calculate the midpoint as the average latitude and longitude
average_latitude = mean(a.coordinate.latitude for a in annotations)
average_longitude = atan2(mean(sin(a.coordinate.longitude) for a in annotations), mean(cos(a.coordinate.longitude) for a in annotations)) // be careful with degrees and radians in real code
regular_midpoint = coordinate(average_latitude, average_longitude)
// subtract 180 from longitude for the midpoint of the region crossing the meridian
meridian_midpoint = coordinate(average_latitude, average_longitude - 180.0)
if (meridian_midpoint.longitude < -180) {
meridian_midpoint.longitude += 360.0
}
// work out which region will be smaller and center map there
meridian_sum = sum(a.coordinate.distance(meridian_midpoint) for a in annotations)
regular_sum = sum(a.coordinate.distance(regular_midpoint) for a in annotations)
regular_max_distance = max(a.coordinate.distance(regular_midpoint) for a in annotations)
if meridian_sum < regular_sum {
meridian_max_distance = max(a.coordinate.distance(meridian_midpoint) for a in annotations)
centerMapWithRadius(meridian_midpoint, max(zoomLimit, meridian_max_distance))
} else {
regular_max_distance = max(a.coordinate.distance(regular_midpoint) for a in annotations)
centerMapWithRadius(regular_midpoint, max(zoomLimit, regular_max_distance))
}
}
この方法は、完全ではありません。