如何使用适用于 iOS 的 google maps sdk 设置区域？

Question

如何使用 google maps sdk for iOS 设置区域？ 我想为标记的位置和半径设置缩放。

Answer 1

更新：

以下原始答案在 SDK 1.2 版中已过时 - 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

---

原答案：

MapKit 中的MKMapPoint 类型定义了地图的二维投影。尽管投影的实际值是不透明的，但它们最终等同于缩放级别 20 的像素。这可用于将纬度/经度值转换为像素，从而转换为比例，从而转换为缩放级别。

首先定义两个位置，指定您要显示的区域的边界。这些可能是边界框的对角，也可能只是两个位置，例如：

CLLocationCoordinate2D location1 = 
    CLLocationCoordinate2DMake(-33.8683, 151.2086); // Sydney
CLLocationCoordinate2D location2 = 
    CLLocationCoordinate2DMake(-31.9554, 115.8585); // Perth

如果您要包含两个以上的点，您可以自己计算它们的边界。这也可以使用GMSCoordinateBounds 来完成，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（以磅为单位）。你可以使用这个：

float mapViewWidth = _mapView.frame.size.width;
float mapViewHeight = _mapView.frame.size.height;

但这只有在您已经创建了地图视图时才有效。另外，如果您使用getting started guide 中的示例代码，则将框架设置为CGRectZero，因为稍后将设置实际大小以填充屏幕。在这些情况下，如果您正在创建全屏地图，那么您可能需要这样的东西：

float mapViewWidth = [UIScreen mainScreen].applicationFrame.size.width;
float mapViewHeight = [UIScreen mainScreen].applicationFrame.size.height;

否则，请使用您在创建地图视图时使用的大小。

现在您有了计算相机位置所需的信息：

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];

然后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。

要编译此代码，您需要将 MapKit 框架添加到您的项目中，然后将其导入：

#import <MapKit/MapKit.h>

请注意，如果您的坐标跨越日期线，则此代码不会处理环绕。例如，如果您尝试将此代码用于东京和夏威夷，而不是显示太平洋地区，它将尝试显示几乎整个世界。在纵向模式下，无法缩小到足以看到左侧的夏威夷和右侧的东京，因此地图最终以非洲为中心，两个位置都不可见。如果你愿意，你可以修改上面的代码来处理日期行的环绕。

Answer 2

更新

所有问题都已在最新版本的 Google 地图 (1.5) 中得到修复。现在可以使用标准方法[mapView_ animateWithCameraUpdate:[GMSCameraUpdate fitBounds:bounds]]; 代替下面的代码

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原始答案

[GMSCameraUpdate fitBounds] 在我的 SDK (1.2.0) 版本中没有给出准确的结果。我正在使用下面的代码而不是它。公式取自Mercator Projection。根据Google Documentation，世界在纬度上以 85 度为界。

#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];


}

Answer 3

Saxun Druce 的回答非常好。但此外，如果您想从任何位置计算半径，您可以使用以下代码：

    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];

Answer 4

如果你有谷歌地图的'far-left'和'near-right'角的纬度和经度，你可以使用下面的代码快速显示数据

     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;

This 链接也可能对相关的事情有所帮助。

Answer 5

我目前正在使用这种方法。

self.markers 是一个字典，其标记由位置 ID 存储，self.currentLocation 是一个 CLLocation2D，self.mapView 是一个 GMSMapView。

这里的数学是检查是否匹配宽度或高度上的大小，然后根据 x1 / pow(2, zoom1) = x2 / pow(2, zoom2 )"，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];
}

Answer 6

根据 GoogleMaps iOS sdk 1.9.2 的新版本， 我们可以使用相机的位置、缩放级别、查看角度进行设置。

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];

供进一步参考see this PDF document。

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];

希望这能解决问题。

Answer 7

我翻遍了框架的头文件，只找到了可以用于下面代码的接口，可以作为一个开始。这里的问题是我在其他标题之一中找不到任何 GMSCoordinateBounds 的导入，所以我找不到在 GMSMapView 中显示该区域的方法。

GMSVisibleRegion region;
region.farLeft = CLLocationCoordinate2DMake(farLeftLatitude, farLeftlongitude);
region.farRight = CLLocationCoordinate2DMake(farRightlatitude, farRightlongitude); 

GMSCoordinateBounds *bounds = [[GMSCoordinateBounds alloc] initWithRegion:region];

Answer 8

截至 2014 年 6 月，this answer 是迭代给定标记数组并相应设置边界的最简单方法。

Answer 9

//我发现这个方法对我有用

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;

      }