用JavaScript计算2分之间的轴承

Question

我想从点1到第2点计算轴承输入格式为52.070564-4.407116

无论我尝试什么，我都无法获得正确的输出。

我使用的公式是：

// koers berekenen
var y = Math.sin(ln-ln1) * Math.cos(lt);
var x = Math.cos(lt1)*Math.sin(lt) -
        Math.sin(lt1)*Math.cos(lt)*Math.cos(ln-ln1);
var radians = Math.atan2(y, x);
var bearing = Math.round(radians * (180/Math.PI));
/* >>>>>> original <<<<<<<
var y = Math.sin(λ2-λ1) * Math.cos(φ2);
var x = Math.cos(φ1)*Math.sin(φ2) -
        Math.sin(φ1)*Math.cos(φ2)*Math.cos(λ2-λ1);
var brng = Math.atan2(y, x).toDegrees();
φ1,λ1 is the start point, φ2,λ2 the end point (Δλ is the difference in longitude)
*/

Answer 1

您可以使用此功能计算轴承：

// Converts from degrees to radians.
function toRadians(degrees) {
  return degrees * Math.PI / 180;
};
 
// Converts from radians to degrees.
function toDegrees(radians) {
  return radians * 180 / Math.PI;
}
function bearing(startLat, startLng, destLat, destLng){
  startLat = toRadians(startLat);
  startLng = toRadians(startLng);
  destLat = toRadians(destLat);
  destLng = toRadians(destLng);
  y = Math.sin(destLng - startLng) * Math.cos(destLat);
  x = Math.cos(startLat) * Math.sin(destLat) -
        Math.sin(startLat) * Math.cos(destLat) * Math.cos(destLng - startLng);
  brng = Math.atan2(y, x);
  brng = toDegrees(brng);
  return (brng + 360) % 360;
}

Answer 2

start_latitude  = 12.9389352
start_longitude = 77.6994306
stop_latitude   = 12.939103
stop_longitude  = 77.705825
var y = Math.sin(stop_longitude-start_longitude) * Math.cos(stop_latitude);
var x = Math.cos(start_latitude)*Math.sin(stop_latitude) -
        Math.sin(start_latitude)*Math.cos(stop_latitude)*Math.cos(stop_longitude-start_longitude);
var brng = Math.atan2(y, x) * 180 / Math.PI;
alert("Bearing in degreee:  " + brng);

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