private static function isOnSegmentGC($lat1, $lng1, $lat2, $lng2, $lat3, $lng3, $havTolerance)
{
$havDist13 = MathUtil::havDistance($lat1, $lat3, $lng1 - $lng3);
if ($havDist13 <= $havTolerance) {
return true;
}
$havDist23 = MathUtil::havDistance($lat2, $lat3, $lng2 - $lng3);
if ($havDist23 <= $havTolerance) {
return true;
}
$sinBearing = self::sinDeltaBearing($lat1, $lng1, $lat2, $lng2, $lat3, $lng3);
$sinDist13 = MathUtil::sinFromHav($havDist13);
$havCrossTrack = MathUtil::havFromSin($sinDist13 * $sinBearing);
if ($havCrossTrack > $havTolerance) {
return false;
}
$havDist12 = MathUtil::havDistance($lat1, $lat2, $lng1 - $lng2);
$term = $havDist12 + $havCrossTrack * (1 - 2 * $havDist12);
if ($havDist13 > $term || $havDist23 > $term) {
return false;
}
if ($havDist12 < 0.74) {
return true;
}
$cosCrossTrack = 1 - 2 * $havCrossTrack;
$havAlongTrack13 = ($havDist13 - $havCrossTrack) / $cosCrossTrack;
$havAlongTrack23 = ($havDist23 - $havCrossTrack) / $cosCrossTrack;
$sinSumAlongTrack = MathUtil::sinSumFromHav($havAlongTrack13, $havAlongTrack23);
return $sinSumAlongTrack > 0;
// Compare with half-circle == PI using sign of sin().
}
/**
* Returns distance on the unit sphere; the arguments are in radians.
*/
private static function distanceRadians($lat1, $lng1, $lat2, $lng2)
{
return MathUtil::arcHav(MathUtil::havDistance($lat1, $lat2, $lng1 - $lng2));
}
