distancecalculator.php

<?php
 
namespace Bitrix\Location\Entity\Location;
 
use Bitrix\Location\Entity\Location;
 
class DistanceCalculator
{
    private const EARTH_RADIUS = 6371;
 
    public function calculate(Location $location1, Location $location2)
    {
        if(
            empty($location1->getLatitude())
            || empty($location1->getLongitude())
            || empty($location2->getLatitude())
            || empty($location2->getLongitude())
        )
        {
            return false;
        }
 
        $lat1 = $location1->getLatitude() / 180 * M_PI;
        $lat2 = $location2->getLatitude() / 180 * M_PI;
        $lon1 = $location1->getLongitude() / 180 * M_PI;
        $lon2 = $location2->getLongitude() / 180 * M_PI;
 
        return (float)acos(sin($lat1)*sin($lat2)
            + cos($lat1)*cos($lat2)
            * cos($lon2-$lon1))
            * self::EARTH_RADIUS;
    }
}