Location\Bearing\BearingSpherical

Complexity

Total Complexity

4

Size/Duplication

Total Lines	73
Duplicated Lines	0 %

Coupling/Cohesion

Components	0
Dependencies	1

Importance

Changes	1
Bugs	0	Features	0

3 Methods

Rating	Name	Duplication	Size	Complexity
A	calculateBearing()	0	18	2
A	calculateFinalBearing()	0	6	1
A	calculateDestination()	0	12	1

<?php
/**
 * Calculation of bearing between two points using a
 * simple spherical model of the earth.
 *
 * @author   Marcus Jaschen <mjaschen@gmail.com>
 * @license  https://opensource.org/licenses/GPL-3.0 GPL
 * @link     https://github.com/mjaschen/phpgeo
 */

namespace Location\Bearing;

use Location\Coordinate;

/**
 * Calculation of bearing between two points using a
 * simple spherical model of the earth.
 *
 * @author   Marcus Jaschen <mjaschen@gmail.com>
 * @license  https://opensource.org/licenses/GPL-3.0 GPL
 * @link     https://github.com/mjaschen/phpgeo
 */
class BearingSpherical implements BearingInterface
{
    /**
     * Earth radius in meters.
     */
    const EARTH_RADIUS = 6371009;

    /**
     * This method calculates the initial bearing between the
     * two points.
     *
     * @param \Location\Coordinate $point1
     * @param \Location\Coordinate $point2
     *
     * @return float Bearing Angle
     */
    public function calculateBearing(Coordinate $point1, Coordinate $point2)
    {
        $lat1 = deg2rad($point1->getLat());
        $lat2 = deg2rad($point2->getLat());
        $lng1 = deg2rad($point1->getLng());
        $lng2 = deg2rad($point2->getLng());

        $y = sin($lng2 - $lng1) * cos($lat2);
        $x = cos($lat1) * sin($lat2) - sin($lat1) * cos($lat2) * cos($lng2 - $lng1);

        $bearing = rad2deg(atan2($y, $x));

        if ($bearing < 0) {
            $bearing = fmod($bearing + 360, 360);
        }

        return $bearing;
    }

    /**
     * Calculates the final bearing between the two points.
     *
     * @param \Location\Coordinate $point1
     * @param \Location\Coordinate $point2
     *
     * @return float
     */
    public function calculateFinalBearing(Coordinate $point1, Coordinate $point2)
    {
        $initialBearing = $this->calculateBearing($point2, $point1);

        return fmod($initialBearing + 180, 360);
    }

    /**
     * Calculates a destination point for the given point, bearing angle,
     * and distance.
     *
     * @param \Location\Coordinate $point
     * @param float $bearing the bearing angle between 0 and 360 degrees
     * @param float $distance the distance to the destination point in meters
     *
     * @return Coordinate
     */
    public function calculateDestination(Coordinate $point, $bearing, $distance)
    {
        $D = $distance / static::EARTH_RADIUS;
        $B = deg2rad($bearing);
        $φ = deg2rad($point->getLat());
        $λ = deg2rad($point->getLng());

        $Φ = asin(sin($φ) * cos($D) + cos($φ) * sin($D) * cos($B));
        $Λ = $λ + atan2(sin($B) * sin($D) * cos($φ), cos($D) - sin($φ) * sin($φ));

        return new Coordinate(rad2deg($Φ), rad2deg($Λ));
    }
}