Calculating Average Coordinates

July 01, 2021

The logic below was taken from the site: https://carto.com/blog/center-of-points/

Where the $coordinates argument is a collection of Coordinates objects. This Coordinates class, should be something like:

    class Coordinates {
        public function __construct(private float $latitude, private float $longitude)
        {}
        
        public function getLat(): float
        {
            return $this->latitude;
        }
        
        public function getLat(): float
        {
            return $this->longitude;
        }
    }

With this set, you can send this data to the method below to get the center of the coordinates in the collection.

    public static function average(Collection $coordinates): array
    {
        $coordinates = $slots->map(function ($coordinates) {
            $latitude = $coordinates->getLat();
            $longitude = $coordinates->getLng();

            return [
                'zeta' => sin(pi() * $longitude / 180),
                'xi' => cos(pi() * $longitude / 180),
                'latitude' => $latitude,
            ];
        });

        $zeta = $coordinates->average('zeta');
        $xi = $coordinates->average('xi');

        $latitude = $coordinates->average('latitude');
        $longitude = 180 * atan2($zeta, $xi) / pi();

        return new Coordinates($latitude, $longitude);
    }