Get coordinates for a bounding box by providing center coordinates and a distance

boundingbox.php

<?php

   /**
     * This function was inspired by this mysql tutorial https://www.youtube.com/watch?v=QgnCB8X_sN4
     * @param  float   $latitude
     * @param  float   $longitude
     * @param  int     $bearing     0 = north, 180 = south, 90 = east, 270 = west
     * @param  int     $distance    m = miles or km = kilometer
     * @param  string  $distance_unit
     *
     *
     * @return array
     */
    public function getBoundingBoxCoords(float $latitude, float $longitude, int $bearing, int $distance, string $distance_unit = 'km'): array
    {

        $radius = match ($distance_unit) {
            'm'     => 3963.1676,
            default => 6378.1,
        };

    //	New latitude in degrees.
    $new_latitude = rad2deg(asin(sin(deg2rad($latitude)) * cos($distance / $radius) + cos(deg2rad($latitude)) * sin($distance / $radius) * cos(deg2rad($bearing))));

    //	New longitude in degrees.
    $new_longitude = rad2deg(deg2rad($longitude) + atan2(sin(deg2rad($bearing)) * sin($distance / $radius) * cos(deg2rad($latitude)), cos($distance / $radius) - sin(deg2rad($latitude)) * sin(deg2rad($new_latitude))));

   $coord = [];
   $coord['lat'] = $new_latitude;
   $coord['lng'] = $new_longitude;

   return $coord;

}