offset static method

ILatLong offset(
  1. ILatLong from,
  2. double distanceInMeter,
  3. double bearing
)

Returns a destination point based on the given distance and bearing

Given a from (start) point, initial bearing, and distance, this will calculate the destination point and final bearing travelling along a (shortest distance) great circle arc.

final Haversine distance = const Haversine();

final num distanceInMeter = (EARTH_RADIUS * math.PI / 4).round();

final p1 = new LatLng(0.0, 0.0);
final p2 = distance.offset(p1, distanceInMeter, 180);

Implementation

//@override
static ILatLong offset(
    final ILatLong from, final double distanceInMeter, double bearing) {
  assert(bearing >= 0 && bearing <= 360);
// bearing: 0: north, 90: east, 180: south, 270: west
  //bearing = 90 - bearing;

  // 0: east, 90: north, +/- 180: west, -90: south
  final double h = bearing / 180 * pi;

  final double a = distanceInMeter / EQUATORIAL_RADIUS;

  final double lat2 = asin(sin(degToRadian(from.latitude)) * cos(a) +
      cos(degToRadian(from.latitude)) * sin(a) * cos(h));

  final double lng2 = degToRadian(from.longitude) +
      atan2(sin(h) * sin(a) * cos(degToRadian(from.latitude)),
          cos(a) - sin(degToRadian(from.latitude)) * sin(lat2));

  return new LatLong(radianToDeg(lat2), radianToDeg(lng2));
}