统一GPS坐标到(X,Y,Z)，向北旋转

Question

我正在用Unity3D制作一个应用程序，它使用GPS坐标在3D世界中放置一个"东西"，当你在现实世界中靠近它时，你会发现它越来越近。有点像PokemonGO

所以问题是:我设法将物体放置在正确的位置和距离上，使用函数dist(lat1,lon1,lat2,lon2)，它给了我两个坐标之间的距离(见下文)。

接下来我想做的是让场景围绕Y轴转向北方(Z轴+应该指向北方)。我该怎么做呢?

我所做的是:

float xx = dist (0, Tlon, 0, lon), zz = dist (Tlat, 0, lat, 0);
Vector3 position = new Vector3 (xx, 0, zz);
position.Normalize ();
float beta = Mathf.Acos(position.z) * Mathf.Rad2Deg;
position = Quaternion.Euler (0,beta-Input.compass.trueHeading,0)*position;
transform.position = position;

但是它做了一些奇怪的事情，"右"的位置既在我的右边又在我的左边(为什么?idk)

{dist函数，用于计算两个坐标之间的距离:}

float dist(float lat1, float lon1, float lat2, float lon2){  // generally used geo measurement function
    var R = 6378.137; // Radius of earth in KM
    var dLat = (lat2 - lat1) * Mathf.PI / 180;
    var dLon = (lon2 - lon1) * Mathf.PI / 180;
    var a = Mathf.Sin(dLat/2) * Mathf.Sin(dLat/2) +
        Mathf.Cos(lat1 * Mathf.PI / 180) * Mathf.Cos(lat2 * Mathf.PI / 180) *
        Mathf.Sin(dLon/2) * Mathf.Sin(dLon/2);
    var c = 2 * Mathf.Atan2(Mathf.Sqrt(a), Mathf.Sqrt(1-a));
    var d = R * c;
    return (float)(d * 1000); // meters
}

Answer 1

最简单的方法是将每个map对象赋值为empty作为父对象，然后旋转。这样，您只需要将transform.rotation = Quaternion.Euler (0,Input.compass.trueHeading,0)设置为空

Input.compass.trueHeading -标题相对于地理北极

看看你的代码应该是这样的:

float xx = dist (0, Tlon, 0, lon), zz = dist (Tlat, 0, lat, 0);
Vector3 position = new Vector3 (xx, 0, zz);
position.Normalize ();
position = Quaternion.AngleAxis(Input.compass.trueHeading, Vector3.up) * position;
transform.position = position;

编辑。我不知道为什么在例子中是一个减号，也许它也应该在我的代码中。

变换。旋转=四元数。欧拉(0 -Input.compass.trueHeading

0);

Answer 2

我实际上找到了一个解决我自己问题的方法，那就是:

我取delta(单位北(z=轴)和实际地理北之间的差)

if (delta == 0 && (gcb.activeSelf||head.transform.eulerAngles.y!=0)) {
    Vector3 fwd = new Vector3 (0, 0, 1);
    Vector3 north = Quaternion.Euler (0, Input.compass.trueHeading, 0) * fwd;
    delta = SignedAngle(fwd,north) + (360-head.transform.eulerAngles.y);
}

然后我计算unityNorth和元素应该放置的位置之间的角度:

float xx = dist (0, Tlon, 0, lon), zz = dist (Tlat, 0, lat, 0);
Vector3 position = new Vector3 (xx, 0, zz); //the position of the target if unityNorth and actual geoNorth were the same
position.Normalize ();
Vector3 unityN = new Vector3 (0,0,1); // unity north
angoloTrgt = Vector3.Angle (unityN, position);
position *= MIN_CUBE_DIST;
target.transform.position = new Vector3 (0,0,MIN_CUBE_DIST);

然后将对象放置在直角

bollettino.transform.RotateAround (Vector3.zero, Vector3.up,  angoloTrgt - old_compass-delta);

其中old_compass是场景加载时Input.compass.trueHeading的值