Question

Marker Movement from source to destination

图像显示标记仅在一个方向上带标记的直线运动。我想沿着折线移动我的标记，标记方向应该与折线方向一起变化。如何实现这一目标。我目前的代码是这样的：

类MapScreenVC：BaseVC {

var path = GMSMutablePath()
var arrayCoordinates : [CLLocationCoordinate2D] = []
var destCoord = CLLocationCoordinate2D()
var marker = GMSMarker()
var mapView : GMSMapView? = nil
override func viewDidLoad() {
    super.viewDidLoad()

    let camera = GMSCameraPosition.camera(withLatitude: 53.4545, longitude: -2.1811, zoom: 14)
    mapView = GMSMapView.map(withFrame: .zero, camera: camera)
    marker = GMSMarker()
    marker.position = CLLocationCoordinate2DMake(53.4387, -2.1827)
    marker.title = "Source"
    marker.snippet = "Source"
    marker.icon = UIImage(named: "car")
    marker.map = mapView



    let DestinationMarker = GMSMarker()
    self.destCoord = CLLocationCoordinate2DMake(53.4645, -2.1873)
    DestinationMarker.position = CLLocationCoordinate2DMake(53.4643, -2.1869)
    DestinationMarker.title = "Destination"
    DestinationMarker.snippet = "Destination"
    DestinationMarker.icon = UIImage(named: "home")
    DestinationMarker.map = mapView

// PolyLine

    path.addLatitude(53.4395, longitude:-2.1834)
    path.addLatitude(53.4403, longitude:-2.1854)
    path.addLatitude(53.4414, longitude:-2.1852)
    path.addLatitude(53.4428, longitude:-2.1832)
    path.addLatitude(53.4442, longitude:-2.1818)
    path.addLatitude(53.4449, longitude:-2.1801)
    path.addLatitude(53.4478, longitude:-2.1793)
    path.addLatitude(53.4504, longitude:-2.1798)
    path.addLatitude(53.4526, longitude:-2.1806)
    path.addLatitude(53.4545, longitude:-2.1811)
    path.addLatitude(53.4564, longitude:-2.1811)
    path.addLatitude(53.4584, longitude:-2.1811)
    path.addLatitude(53.4601, longitude:-2.1811)
    path.addLatitude(53.4617, longitude:-2.1821)
    path.addLatitude(53.4630, longitude:-2.1829)
    path.addLatitude(53.4632, longitude:-2.1851)
    path.addLatitude(53.4635, longitude:-2.1869)
    path.addLatitude(53.4638, longitude:-2.1882)
    path.addLatitude(53.4645, longitude:-2.1873)


    let polyline = GMSPolyline(path: path)
    polyline.strokeColor = .blue
    polyline.strokeWidth = 6.0
    polyline.geodesic = true
    polyline.map = mapView
    updateMarker(coordinates: destCoord)
    view = mapView
}

func updateMarker(coordinates: CLLocationCoordinate2D) {
    CATransaction.begin()
    CATransaction.setAnimationDuration(10.0)
    marker.position = coordinates
    CATransaction.commit()
}

}

Answer 1

我不熟悉可以为您提供此功能的库或类似功能，因此我将概述一种可以轻松实现此操作的手动方法。

要在折线上移动标记，您需要计算标记需要从每个点获取的步数，以便到达下一个点。
一种选择是为定义折线的每条线执行以下操作：
1）为每2个点定义一条线f(x) = ax + b 如果您在计算线的斜率时需要帮助，可以进一步阅读here（a在上面的等式中）

2）定义标记所需的步骤，直到到达该行的末尾。您可以将线的长度除以常数，这将为您提供常量step。这不是理想的，因为跨越短线和长线需要相同数量的步骤，但这是一个开始。另请注意，2个lat / lng点之间的距离在球体上，并不像2维中那么简单。查看https://en.wikipedia.org/wiki/Haversine_formula了解更多信息。

3）将标记放在第一个点(x1,y1)上，然后将其移至(x1+step, f(x1+step)) 您需要确定是否在线上向左或向右移动。

4）每次移动标记后，检查它是否到达当前行的终点，然后重新开始下一行。

如何沿折线精确移动标记？

1 个答案: