/**
* testCalculateDestinationForBearingAndDistanceReturnsExpectedValue
*
* @param LatLong $latLong The starting point.
* @param float $bearing The initial bearing.
* @param float $distance The distance in metres to travel.
* @param LatLong $expected The expected destination.
*
* @dataProvider getLatLongWithInitialBearingDistanceAndDestination
*/
public function testCalculateDestinationForBearingAndDistanceReturnsExpectedValue(LatLong $latLong, $bearing, $distance, LatLong $expected)
{
$actual = $latLong->calculateDestinationForBearingAndDistance($bearing, $distance);
$tolerance = 0.3;
$this->assertEqualsWithinTolerance($expected->getLatitude(), $actual->getLatitude(), $tolerance);
$this->assertEqualsWithinTolerance($expected->getLongitude(), $actual->getLongitude(), $tolerance);
$this->assertEquals($latLong->getHeight(), $actual->getHeight());
// Height remains constant.
$this->assertEquals($expected->getDatum(), $actual->getDatum());
}
/**
* Calculate the initial bearing (forward azimuth) to follow from this point to arrive at the given destination.
*
* @param LatLong $destination The destination.
*
* @return float The bearing in decimal degrees.
*/
public function calculateInitialBearing(LatLong $destination)
{
$latRad = $this->getLatitudeRadians();
$destLatRad = $destination->getLatitudeRadians();
$diffLongRad = deg2rad($destination->getLongitude() - $this->getLongitude());
$x = cos($latRad) * sin($destLatRad) - sin($latRad) * cos($destLatRad) * cos($diffLongRad);
$y = sin($diffLongRad) * cos($destLatRad);
$bearing = atan2($y, $x);
return fmod(rad2deg($bearing) + 360, 360);
}