将MKCoordinateRegion转换为MKMapRect

时间:2012-02-14 00:50:18

标签: ios mkmapview mkcoordinateregion mkmaprect

我的应用程序中有一个方形MKMapView,我希望设置一个中心点和视图的确切高度/宽度(以米为单位)。

创建MKCoordinateRegion并将地图设置为它(如此代码中所示......

MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance(center_coord, 1000.0, 1000.0);
[self.mapView setRegion:region animated:YES];

..)无法正常工作,因为在这里使用区域只意味着至少显示该区域,通常比区域更多。


我打算使用setVisibleMapRect:animated:方法,因为我相信这会缩放到实际传递的MKMapRect

那么,有没有一种简单的方法可以在MKcoordinateRegion和MKMapRect之间进行转换?也许获得该区域的左上角和右下角坐标,并使用它们来制作MKMapRect?

我在Map Kit Functions Reference中看不到任何方便的东西。

(使用iOS 5,Xcode 4.2)

10 个答案:

答案 0 :(得分:53)

要添加另一个实现:

- (MKMapRect)MKMapRectForCoordinateRegion:(MKCoordinateRegion)region
{
    MKMapPoint a = MKMapPointForCoordinate(CLLocationCoordinate2DMake(
        region.center.latitude + region.span.latitudeDelta / 2, 
        region.center.longitude - region.span.longitudeDelta / 2));
    MKMapPoint b = MKMapPointForCoordinate(CLLocationCoordinate2DMake(
        region.center.latitude - region.span.latitudeDelta / 2, 
        region.center.longitude + region.span.longitudeDelta / 2));
    return MKMapRectMake(MIN(a.x,b.x), MIN(a.y,b.y), ABS(a.x-b.x), ABS(a.y-b.y));
}

注意:有许多方法可以在MKMapRectMKCoordinateRegion之间进行转换。这个肯定是 MKCoordinateRegionMakeWithDistance()的确切倒数,但相当接近它。所以,要小心来回转换,因为信息可能会丢失。

答案 1 :(得分:26)

这是对Leo& amp;的一个Swift版本。巴恩哈特解决方案

func MKMapRectForCoordinateRegion(region:MKCoordinateRegion) -> MKMapRect {
    let topLeft = CLLocationCoordinate2D(latitude: region.center.latitude + (region.span.latitudeDelta/2), longitude: region.center.longitude - (region.span.longitudeDelta/2))
    let bottomRight = CLLocationCoordinate2D(latitude: region.center.latitude - (region.span.latitudeDelta/2), longitude: region.center.longitude + (region.span.longitudeDelta/2))

    let a = MKMapPointForCoordinate(topLeft)
    let b = MKMapPointForCoordinate(bottomRight)

    return MKMapRect(origin: MKMapPoint(x:min(a.x,b.x), y:min(a.y,b.y)), size: MKMapSize(width: abs(a.x-b.x), height: abs(a.y-b.y)))
}

答案 2 :(得分:12)

使用MKMapPointForCoordinate转换区域的2个点(顶部/左侧和底部/右侧),然后使用2个MKMapPoints创建MKMapRect

        CLLocationCoordinate2D coordinateOrigin = CLLocationCoordinate2DMake(latitude, longitude);
        CLLocationCoordinate2D coordinateMax = CLLocationCoordinate2DMake(latitude + cellSize, longitude + cellSize);

        MKMapPoint upperLeft = MKMapPointForCoordinate(coordinateOrigin);
        MKMapPoint lowerRight = MKMapPointForCoordinate(coordinateMax);

        MKMapRect mapRect = MKMapRectMake(upperLeft.x,
                                          upperLeft.y,
                                          lowerRight.x - upperLeft.x,
                                          lowerRight.y - upperLeft.y);

答案 3 :(得分:9)

您可以使用方法将MKCoordinateRegion转换为CGRect

- (CGRect)convertRegion:(MKCoordinateRegion)region toRectToView:(UIView *)view

并使用- (MKMapRect)mapRectForRect:(CGRect)rect

或使用MKMapPointForCoordinate方法首先将坐标转换为MKPoint并使用该方法形成MKMapRect以最终使用setVisibleMapRect:animated:

答案 4 :(得分:9)

@Bogdan

我认为应该是:

 CLLocationCoordinate2D topLeftCoordinate =
CLLocationCoordinate2DMake(coordinateRegion.center.latitude
                           + (coordinateRegion.span.latitudeDelta/2.0),
                           coordinateRegion.center.longitude
                           - (coordinateRegion.span.longitudeDelta/2.0));

MKMapPoint topLeftMapPoint = MKMapPointForCoordinate(topLeftCoordinate);

CLLocationCoordinate2D bottomRightCoordinate =
CLLocationCoordinate2DMake(coordinateRegion.center.latitude
                           - (coordinateRegion.span.latitudeDelta/2.0),
                           coordinateRegion.center.longitude
                           + (coordinateRegion.span.longitudeDelta/2.0));

MKMapPoint bottomRightMapPoint = MKMapPointForCoordinate(bottomRightCoordinate);

MKMapRect mapRect = MKMapRectMake(topLeftMapPoint.x,
                                  topLeftMapPoint.y,
                                  fabs(bottomRightMapPoint.x-topLeftMapPoint.x),
                                  fabs(bottomRightMapPoint.y-topLeftMapPoint.y));

根据apple api reference,MKCoordinateRegion.center代表该地区的中心点; 和MKCoordinateSpan.latitudeDelta表示要在地图上显示的北 - 南距离(以度为单位)的数量; MKCoordinateSpan.longitudeDelta表示要为地图区域显示的东西距离(以度为单位)的数量。

答案 5 :(得分:2)

@ David的回答,在Swift 3中

func mapRect(region: MKCoordinateRegion) -> MKMapRect {
  let topLeft = CLLocationCoordinate2D(
    latitude: region.center.latitude + (region.span.latitudeDelta/2.0),
    longitude: region.center.longitude - (region.span.longitudeDelta/2.0)
  )

  let bottomRight = CLLocationCoordinate2D(
    latitude: region.center.latitude - (region.span.latitudeDelta/2.0),
    longitude: region.center.longitude + (region.span.longitudeDelta/2.0)
  )

  let topLeftMapPoint = MKMapPointForCoordinate(topLeft)
  let bottomRightMapPoint = MKMapPointForCoordinate(bottomRight)

  let origin = MKMapPoint(x: topLeftMapPoint.x,
                          y: topLeftMapPoint.y)
  let size = MKMapSize(width: fabs(bottomRightMapPoint.x - topLeftMapPoint.x),
                       height: fabs(bottomRightMapPoint.y - topLeftMapPoint.y))

  return MKMapRect(origin: origin, size: size)
}

答案 6 :(得分:1)

@David给出的答案(因此,@ onmyway133的Swift 3版本)在东半球(经度0度到180度)到西半球(经度)越过反子午线时会出现重大错误-180度到0度)。 MKMapRect的宽度将大于应有的宽度(通常更大)。

这是修复(对于Swift 3代码):

let topLeftMapPoint = MKMapPointForCoordinate(topLeft)
let bottomRightMapPoint = MKMapPointForCoordinate(bottomRight)
var width = bottomRightMapPoint.x - topLeftMapPoint.x
if width < 0.0 {
    // Rect crosses from the Eastern Hemisphere to the Western Hemisphere
    width += MKMapPointForCoordinate(CLLocationCoordinate2D(latitude: 0.0, longitude: 180.0)).x
}
let height = bottomRightMapPoint.y - topLeftMapPoint.y
let size = MKMapSize(width: width, height: height)
return MKMapRect(origin: topLeftMapPoint, size: size)

使用MKCoordinateRegion,使用上面的代码将其转换为MKMapRect,然后使用MKCoordinateRegionForMapRect()将其转换回MKCoordinateRegion,这使我在地图上的输入区域和输出区域之间达成了很好的一致。

答案 7 :(得分:1)

要经过子午线(以及缠绕两极)还需要更加小心,否则MKMapPointForCoordinate会返回-1,-1:

public func MKMapRectForCoordinateRegion(region:MKCoordinateRegion) -> MKMapRect {
var topLeft = CLLocationCoordinate2D(
    latitude: min(region.center.latitude + (region.span.latitudeDelta/2.0), 90),
    longitude: region.center.longitude - (region.span.longitudeDelta/2.0)
)

if topLeft.longitude < -180 {
    // We wrapped around the meridian
    topLeft.longitude += 360
}

var bottomRight = CLLocationCoordinate2D(
    latitude: max(region.center.latitude - (region.span.latitudeDelta/2.0), -90),
    longitude: region.center.longitude + (region.span.longitudeDelta/2.0)
)

    if bottomRight.longitude > 180 {
        // We wrapped around the medridian
        bottomRight.longitude -= 360
    }

    let topLeftMapPoint = MKMapPointForCoordinate(topLeft)
    let bottomRightMapPoint = MKMapPointForCoordinate(bottomRight)

    var width = bottomRightMapPoint.x - topLeftMapPoint.x
    if width < 0.0 {
        // Rect crosses meridian
        width += MKMapPointForCoordinate(CLLocationCoordinate2D(latitude: 0.0, longitude: 180.0)).x
    }
    let height = bottomRightMapPoint.y - topLeftMapPoint.y
    let size = MKMapSize(width: width, height: height)

    return MKMapRect(origin: topLeftMapPoint, size: size)
}

一些测试用例代码(使用Nimble):

func testMKMapRectForCoordinateRegion() {
    let northWesternRegion = MKCoordinateRegionMake(CLLocationCoordinate2DMake(45.0, -90.0), MKCoordinateSpanMake(20.0, 20.0))
    let northWesternMapRect = MKMapRectForCoordinateRegion(region: northWesternRegion)
    let convertedNWRegion = MKCoordinateRegionForMapRect(northWesternMapRect)
    expect(self.equivalentRegions(northWesternRegion, convertedNWRegion)).to(beTrue())

    let northEasternRegion = MKCoordinateRegionMake(CLLocationCoordinate2DMake(45.0, 90.0), MKCoordinateSpanMake(20.0, 20.0))
    let northEasternMapRect = MKMapRectForCoordinateRegion(region: northEasternRegion)
    let convertedNERegion = MKCoordinateRegionForMapRect(northEasternMapRect)
    expect(self.equivalentRegions(northEasternRegion, convertedNERegion)).to(beTrue())

    let southWesternRegion = MKCoordinateRegionMake(CLLocationCoordinate2DMake(-45.0, -90.0), MKCoordinateSpanMake(20.0, 20.0))
    let southWesternMapRect = MKMapRectForCoordinateRegion(region: southWesternRegion)
    let convertedSWRegion = MKCoordinateRegionForMapRect(southWesternMapRect)
    expect(self.equivalentRegions(southWesternRegion, convertedSWRegion)).to(beTrue())

    let southEasternRegion = MKCoordinateRegionMake(CLLocationCoordinate2DMake(-45.0, 90.0), MKCoordinateSpanMake(20.0, 20.0))
    let southEasternMapRect = MKMapRectForCoordinateRegion(region: southEasternRegion)
    let convertedSERegion = MKCoordinateRegionForMapRect(southEasternMapRect)
    expect(self.equivalentRegions(southEasternRegion, convertedSERegion)).to(beTrue())

    let meridianSpanEastRegion = MKCoordinateRegionMake(CLLocationCoordinate2DMake(0.0, 170.0), MKCoordinateSpanMake(20.0, 20.0))
    let meridianSpanEastMapRect = MKMapRectForCoordinateRegion(region: meridianSpanEastRegion)
    let convertedMeridianSpanEastRegion = MKCoordinateRegionForMapRect(meridianSpanEastMapRect)
    expect(self.equivalentRegions(meridianSpanEastRegion, convertedMeridianSpanEastRegion)).to(beTrue())

    let meridianSpanWestRegion = MKCoordinateRegionMake(CLLocationCoordinate2DMake(0.0, -170.0), MKCoordinateSpanMake(20.0, 20.0))
    let meridianSpanWestMapRect = MKMapRectForCoordinateRegion(region: meridianSpanWestRegion)
    let convertedMeridianSpanWestRegion = MKCoordinateRegionForMapRect(meridianSpanWestMapRect)
    expect(self.equivalentRegions(meridianSpanWestRegion, convertedMeridianSpanWestRegion)).to(beTrue())
}

fileprivate func equivalentRegions(_ regionA: MKCoordinateRegion, _ regionB: MKCoordinateRegion) -> Bool {
    // Allow a small delta between values
    let deltaAllowed: Double = 1.0

    return (fabs(regionA.center.latitude - regionB.center.latitude) < deltaAllowed) &&
            (fabs(regionA.center.longitude - regionB.center.longitude) < deltaAllowed) &&
            (fabs(regionA.span.latitudeDelta - regionB.span.latitudeDelta) < deltaAllowed) &&
            (fabs(regionA.span.longitudeDelta - regionB.span.longitudeDelta) < deltaAllowed)
}

答案 8 :(得分:0)

使用内置函数MKCoordinateRegionForMapRect

MKCoordinateRegion region = MKCoordinateRegionForMapRect(rect);

答案 9 :(得分:0)

Swift 5.1:

func mapRectForCoordinateRegion(_ region: MKCoordinateRegion) -> MKMapRect {
   let topLeftCoordinate = CLLocationCoordinate2DMake(region.center.latitude + (region.span.latitudeDelta / 2.0), region.center.longitude - (region.span.longitudeDelta / 2.0))
   let topLeftMapPoint = MKMapPoint(topLeftCoordinate)
   let bottomRightCoordinate = CLLocationCoordinate2DMake(region.center.latitude - (region.span.latitudeDelta / 2.0), region.center.longitude + (region.span.longitudeDelta / 2.0))
   let bottomRightMapPoint = MKMapPoint(bottomRightCoordinate)
   return MKMapRect(x: topLeftMapPoint.x, y: topLeftMapPoint.y, width: fabs(bottomRightMapPoint.x - topLeftMapPoint.x), height: fabs(bottomRightMapPoint.y - topLeftMapPoint.y))

}