更新:
原先的回答已经过时,从SDK版本1.2开始,您现在可以使用GMSCameraUpdate
类的fitBounds:
方法:
https://developers.google.com/maps/documentation/ios/reference/interface_g_m_s_camera_update
原始回答:
MapKit
中的MKMapPoint
类型定义了地图的二维投影。尽管投影的实际值应该是不透明的,但它们等同于缩放级别为20的像素。这可以用来将纬度/经度值转换为像素,因此可以得到一个比例尺和缩放级别。
首先定义两个位置,这些位置指定要显示的区域的边界。它们可以是边界框的相对角落,也可以只是两个位置,例如:
CLLocationCoordinate2D location1 =
CLLocationCoordinate2DMake(-33.8683, 151.2086); // Sydney
CLLocationCoordinate2D location2 =
CLLocationCoordinate2DMake(-31.9554, 115.8585); // Perth
如果你有超过两个想要包含的点,你可以自己计算它们的边界。这也可以使用GMSCoordinateBounds
完成,例如:
GMSCoordinateBounds* bounds =
[[GMSCoordinateBounds alloc]
initWithCoordinate: CLLocationCoordinate2DMake(-33.8683, 151.2086) // Sydney
andCoordinate: CLLocationCoordinate2DMake(-31.9554, 115.8585)]; // Perth
bounds = [bounds including:
CLLocationCoordinate2DMake(-12.4667, 130.8333)]; // Darwin
CLLocationCoordinate2D location1 = bounds.southWest;
CLLocationCoordinate2D location2 = bounds.northEast;
接下来,您需要获取地图视图的大小(以点为单位)。您可以使用以下代码:
float mapViewWidth = _mapView.frame.size.width;
float mapViewHeight = _mapView.frame.size.height;
但是这只适用于您已经创建了地图视图的情况。另外,如果您正在使用入门指南中的示例代码,则框架被设置为CGRectZero
,因为实际大小将稍后设置以填充屏幕。在这些情况下,如果您要创建全屏地图,则可能需要像这样:
float mapViewWidth = [UIScreen mainScreen].applicationFrame.size.width;
float mapViewHeight = [UIScreen mainScreen].applicationFrame.size.height;
MKMapPoint point1 = MKMapPointForCoordinate(location1);
MKMapPoint point2 = MKMapPointForCoordinate(location2);
MKMapPoint centrePoint = MKMapPointMake(
(point1.x + point2.x) / 2,
(point1.y + point2.y) / 2);
CLLocationCoordinate2D centreLocation = MKCoordinateForMapPoint(centrePoint);
double mapScaleWidth = mapViewWidth / fabs(point2.x - point1.x);
double mapScaleHeight = mapViewHeight / fabs(point2.y - point1.y);
double mapScale = MIN(mapScaleWidth, mapScaleHeight);
double zoomLevel = 20 + log2(mapScale);
GMSCameraPosition *camera = [GMSCameraPosition
cameraWithLatitude: centreLocation.latitude
longitude: centreLocation.longitude
zoom: zoomLevel];
您可以使用此相机初始化地图视图,或将地图视图设置为此相机。
要使此代码编译,您需要将MapKit框架添加到您的项目中,并导入它:
#import <MapKit/MapKit.h>
请注意,如果您的坐标跨越日期线,此代码将无法处理环绕。例如,如果您尝试在东京和夏威夷使用此代码,则不会显示太平洋地区,而会尝试显示几乎整个世界。在纵向模式下,无法缩放到足以在左侧看到夏威夷和右侧看到东京,因此地图最终以非洲为中心,两个地点都不可见。如果您希望处理日期线上的环绕,可以修改上述代码。
更新
所有问题都已在最新版本的Google Maps(1.5)中解决。现在可以使用标准方法[mapView_ animateWithCameraUpdate:[GMSCameraUpdate fitBounds:bounds]];
,而不是下面的代码。
原始答案
[GMSCameraUpdate fitBounds]
在我的SDK版本(1.2.0)中无法给出精确结果。我使用下面的代码代替它。公式来自墨卡托投影。根据Google文档,世界在纬度上的边界为85度。
#import <stdlib.h>
-(void) animateBoundsNorth:(CGFloat)north West:(CGFloat)west South:(CGFloat)south East:(CGFloat)east Padding:(int)padding {
CGFloat northRad = north * M_PI / 180.0;
CGFloat northProj = logf(tanf(M_PI_4 + northRad/2.0));
CGFloat southRad = south * M_PI / 180.0;
CGFloat southProj = logf(tanf(M_PI_4 + southRad/2.0));
CGFloat topRad = 85.0 * M_PI / 180.0;
CGFloat topProj = logf(tanf(M_PI_4 + topRad/2.0));
CGFloat zoomLat = log2f((mapView_.bounds.size.height - padding * 2) * 2 * topProj /(northProj - southProj)) - 8;
CGFloat zoomLon = log2f((mapView_.bounds.size.width - padding * 2) * 360/(east - west)) - 8;
GMSCameraUpdate *update = [GMSCameraUpdate setTarget:CLLocationCoordinate2DMake((north+south)/2.0, (west+east)/2.0) zoom:MIN(zoomLat, zoomLon)];
[mapView_ animateWithCameraUpdate:update];
}
CLLocationCoordinate2D center = CLLocationCoordinate2DMake([currentLocationLat doubleValue],[currentLocationLong doubleValue]);
float radius = 25*1000; //radius in meters (25km)
MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(center, radius*2, radius*2);
CLLocationCoordinate2D northEast = CLLocationCoordinate2DMake(region.center.latitude - region.span.latitudeDelta/2, region.center.longitude - region.span.longitudeDelta/2);
CLLocationCoordinate2D southWest = CLLocationCoordinate2DMake(region.center.latitude + region.span.latitudeDelta/2, region.center.longitude + region.span.longitudeDelta/2);
GMSCoordinateBounds* bounds = [[GMSCoordinateBounds alloc]
initWithCoordinate: northEast
andCoordinate: southWest];
var region:GMSVisibleRegion = GMSVisibleRegion()
region.nearLeft = CLLocationCoordinate2DMake(nearleflat, nearleftlong)
region.farRight = CLLocationCoordinate2DMake(fareastlat,fareastlong)
let bounds = GMSCoordinateBounds(coordinate: region.nearLeft,coordinate: region.farRight)
let camera = googleMapView.cameraForBounds(bounds, insets:UIEdgeInsetsZero)
googleMapView.camera = camera;
这个链接也可能有助于相关事项。
我目前使用的方法如下。
self.markers是一个按位置ID存储标记的字典,self.currentLocation是CLLocation2D类型,self.mapView是GMSMapView类型。
这里的数学计算是检查是否匹配宽度或高度的大小,然后根据x1 / pow(2, zoom1) = x2 / pow(2, zoom2)的事实进行缩放计算,导致zoom2 = log2(x2 * pow(2, self.mapView.camera.zoom) / x1)。
- (void)fitMarkers
{
if (2 > self.markers.count)
{
[self.mapView animateToCameraPosition:[GMSCameraPosition cameraWithTarget:self.currentLocation.coordinate zoom:kZoom]];
return;
}
NSArray* markers = self.markers.allValues;
GMSCoordinateBounds* markerBounds = [[GMSCoordinateBounds alloc] initWithCoordinate:((id<GMSMarker>)markers[0]).position andCoordinate:((id<GMSMarker>)markers[1]).position];
for (id<GMSMarker> marker in markers)
{
markerBounds = [markerBounds including:marker.position];
}
// get marker bounds in points
CGPoint markerBoundsTopLeft = [self.mapView.projection pointForCoordinate:CLLocationCoordinate2DMake(markerBounds.northEast.latitude, markerBounds.southWest.longitude)];
CGPoint markerBoundsBottomRight = [self.mapView.projection pointForCoordinate:CLLocationCoordinate2DMake(markerBounds.southWest.latitude, markerBounds.northEast.longitude)];
// get user location in points
CGPoint currentLocation = [self.mapView.projection pointForCoordinate:self.currentLocation.coordinate];
CGPoint markerBoundsCurrentLocationMaxDelta = CGPointMake(MAX(fabs(currentLocation.x - markerBoundsTopLeft.x), fabs(currentLocation.x - markerBoundsBottomRight.x)), MAX(fabs(currentLocation.y - markerBoundsTopLeft.y), fabs(currentLocation.y - markerBoundsBottomRight.y)));
// the marker bounds centered on self.currentLocation
CGSize centeredMarkerBoundsSize = CGSizeMake(2.0 * markerBoundsCurrentLocationMaxDelta.x, 2.0 * markerBoundsCurrentLocationMaxDelta.y);
// inset the view bounds to fit markers
CGSize insetViewBoundsSize = CGSizeMake(self.mapView.bounds.size.width - kMarkerSize / 2.0 - kMarkerMargin, self.mapView.bounds.size.height - kMarkerSize / 2.0 - kMarkerSize);
CGFloat x1;
CGFloat x2;
// decide which axis to calculate the zoom level with by comparing the width/height ratios
if (centeredMarkerBoundsSize.width / centeredMarkerBoundsSize.height > insetViewBoundsSize.width / insetViewBoundsSize.height)
{
x1 = centeredMarkerBoundsSize.width;
x2 = insetViewBoundsSize.width;
}
else
{
x1 = centeredMarkerBoundsSize.height;
x2 = insetViewBoundsSize.height;
}
CGFloat zoom = log2(x2 * pow(2, self.mapView.camera.zoom) / x1);
GMSCameraPosition* camera = [GMSCameraPosition cameraWithTarget:self.currentLocation.coordinate zoom:zoom];
[self.mapView animateToCameraPosition:camera];
}
GMSCameraPosition* camera = [GMSCameraPosition cameraWithLatitude:28.6100
longitude:77.2300
zoom:14.0
bearing:0
viewingAngle:0.00];
self.mapView = [GMSMapView mapWithFrame:CGRectMake(0, 45, self.view.frame.size.width, self.view.frame.size.height - 45) camera:camera];
mapView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;
mapView.delegate = self;
mapView.myLocationEnabled = YES;
mapView.mapType = kGMSTypeTerrain;
mapView.settings.compassButton = YES;
mapView.settings.myLocationButton = YES;
[self.mapView setMinZoom:10 maxZoom:18];
GMSMarker* marker = [[GMSMarker alloc] init];
marker.position = CLLocationCoordinate2DMake(28.6100, 77.2300);
marker.title = @"New Delhi";
marker.snippet = @"Capital Of India";
marker.map = self.mapView;
marker.appearAnimation = kGMSMarkerAnimationPop;
marker.icon = [GMSMarker markerImageWithColor:[UIColor grayColor]];
[self.view addSubview:self.mapView];
如需进一步参考,请查看此PDF文档。
您还可以根据需要设置最小和最大缩放级别:
[self.mapView setMinZoom:10 maxZoom:30];
// 我找到了适合我的方法
func setMapZoomToRadius(lat:Double, lng:Double, var mile:Double)
{
let center = CLLocationCoordinate2DMake(lat, lng)
let radius: Double = (mile ) * 621.371
let region = MKCoordinateRegionMakeWithDistance(center, radius * 2.0, radius * 2.0)
let northEast = CLLocationCoordinate2DMake(region.center.latitude - region.span.latitudeDelta, region.center.longitude - region.span.longitudeDelta)
let southWest = CLLocationCoordinate2DMake(region.center.latitude + region.span.latitudeDelta, region.center.longitude + region.span.longitudeDelta)
print("\(region.center.longitude) \(region.span.longitudeDelta)")
let bounds = GMSCoordinateBounds(coordinate: southWest, coordinate: northEast)
let camera = googleMapView.cameraForBounds(bounds, insets:UIEdgeInsetsZero)
googleMapView.camera = camera;
}
我在框架的头文件中搜索,只找到了以下代码可以使用的接口,这可能是一个开始。问题在于我找不到任何其他头文件中GMSCoordinateBounds的导入,因此我找不到在GMSMapView中显示此区域的方法。
GMSVisibleRegion region;
region.farLeft = CLLocationCoordinate2DMake(farLeftLatitude, farLeftlongitude);
region.farRight = CLLocationCoordinate2DMake(farRightlatitude, farRightlongitude);
GMSCoordinateBounds *bounds = [[GMSCoordinateBounds alloc] initWithRegion:region];
MKMapPoint
相当于缩放级别为20的像素。如果您的边界非常小,则mapScale
最终会大于1.0,因此zoomLevel
将最终大于20。如果缩放级别大于SDK的限制,则它将将缩放级别夹紧到其支持的范围内。 - Saxon Druce