destinationPointByDistanceAndBearing static method

LatLng destinationPointByDistanceAndBearing(LatLng l, num distance, num bearing, [ num? radius, ])

Calculates the coordinates of a destination point based on a starting point, a distance, a direction (bearing), and optionally a radius.

l - The LatLng coordinates of the starting point.

distance - The distance in meters to travel from the starting point.

bearing - The direction or bearing in degrees (0 to 360) from the starting point (0 degrees points north, 90 degrees points east, etc.).

radius - The radius of the Earth or the sphere being considered. It is an optional parameter and defaults to the Earth's radius (6371e3 meters).

Returns a new LatLng object representing the coordinates of the destination point.

Implementation

static LatLng destinationPointByDistanceAndBearing(
    LatLng l, num distance, num bearing,
    [num? radius]) {
  radius = radius ?? 6371e3;
  final num angularDistanceRadius = distance / radius;
  final num bearingRadians = degToRadian(bearing as double);

  final num latRadians = degToRadian(l.latitude);
  final num lngRadians = degToRadian(l.longitude);

  final num sinLatRadians = sin(latRadians);
  final num cosLatRadians = cos(latRadians);
  final num sinAngularDistanceRadius = sin(angularDistanceRadius);
  final num cosAngularDistanceRadius = cos(angularDistanceRadius);
  final num sinBearingRadians = sin(bearingRadians);
  final num cosBearingRadians = cos(bearingRadians);

  final sinLatRadians2 = sinLatRadians * cosAngularDistanceRadius +
      cosLatRadians * sinAngularDistanceRadius * cosBearingRadians;
  final num latRadians2 = asin(sinLatRadians2);
  final y = sinBearingRadians * sinAngularDistanceRadius * cosLatRadians;
  final x = cosAngularDistanceRadius - sinLatRadians * sinLatRadians2;
  final num lngRadians2 = lngRadians + atan2(y, x);

  return LatLng(radianToDeg(latRadians2.toDouble()),
      (radianToDeg(lngRadians2.toDouble()) + 540.0) % 360.0 - 180.0);
}