direction method

double direction(
  1. GeoData target
)

Calculate the direction between tow points.

target: Target geoData.

Implementation

double direction(GeoData target) {
  final y2 = pi * target.longitude / 180.0;
  final y1 = pi * longitude / 180.0;
  final x2 = pi * target.latitude / 180.0;
  final x1 = pi * latitude / 180.0;
  final w = 180 *
      atan2(
        sin(x2 - x1),
        cos(y1) * tan(y2) - sin(y1) * cos(x2 - x1),
      ) /
      pi;
  return w - 90;
}