本文介绍了将MKMapView缩放到CLRegion的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!
问题描述
我在iOS5上使用CLGeocoder获得了CLPlacemark.现在,我想获取一个地标的区域(CLRegion对象),然后将我的MKMapView缩放到该区域,这到底有可能吗?
I am getting a CLPlacemark using the CLGeocoder on iOS5. Now I would like to take the region (CLRegion object) of a placemark and have my MKMapView zoom to that region, how on earth is this possible?
我想要此的逆,但是似乎没有-locationFromLocationWithDistance:
或等效方法.我希望没有人说您必须反向使用Haversine公式,因为这看起来有点复杂...
I want the inverse of this, but there seems to be no -locationFromLocationWithDistance:
or equivalent method. I'm hoping nobody says you have to use the Haversine formula in reverse because that looks a tad complicated...
推荐答案
您可以使用此处.对于代码
CLLocationCoordinate2D center = placemark.location.coordinate;
CLRegion* coreLocationRegion = placemark.region;
CLLocationDistance radius = coreLocationRegion.radius;
#define kBEARING_NORTH 0.0
#define kBEARING_EAST .5 * M_PI
#define kBEARING_SOUTH M_PI
#define kBEARING_WEST 1.5 * M_PI
#define kEARTH_RADIUS_M 6371000.0
// Store the angular distance of each side from the center
double angDist = radius / kEARTH_RADIUS_M;
// Convert center lat and lng to radians
double centerLatRad = center.latitude * M_PI / 180;
double centerLngRad = center.longitude * M_PI / 180;
// Calculate latitude range
double maxLatRad = asin(sin(centerLatRad) * cos(angDist) +
cos(centerLatRad) * sin(angDist) * cos(kBEARING_NORTH));
double minLatRad = asin(sin(centerLatRad) * cos(angDist) +
cos(centerLatRad) * sin(angDist) * cos(kBEARING_SOUTH));
// Calculate longitude range
// Longitude range requires coresponding latitudes:
double tempLatRad;
// Calculate max longitude
tempLatRad = asin(sin(centerLatRad) * cos(angDist) +
cos(centerLatRad) * sin(angDist) * cos(kBEARING_EAST));
double maxLngRad = centerLngRad + atan2(sin(kBEARING_EAST) * sin(angDist) * cos(centerLatRad),
cos(angDist) - sin(centerLatRad) * sin(tempLatRad));
// Calculate min longitude
tempLatRad = asin(sin(centerLatRad) * cos(angDist) +
cos(centerLatRad) * sin(angDist) * cos(kBEARING_WEST));
double minLngRad = centerLngRad + atan2(sin(kBEARING_WEST) * sin(angDist) * cos(centerLatRad),
cos(angDist) - sin(centerLatRad) * sin(tempLatRad));
CLLocationDegrees latitudeDelta = (maxLatRad-minLatRad) * 180 / M_PI;
CLLocationDegrees longitudeDelta = (maxLngRad-minLngRad) * 180 / M_PI;
MKCoordinateSpan span = MKCoordinateSpanMake(latitudeDelta, longitudeDelta);
MKCoordinateRegion region = MKCoordinateRegionMake(center, span);
[self.mapView setRegion: region animated: YES];
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