Distance between 2 points in a map

Question

Hello everyone i am searching for a php function to calculate the distance between two points in a google map without the need to use a package /api

your help will be much appreciated and thank you in advance

Answer 1

Here’s a pair of PHP functions that make the calculation easy.

In the first, we find the distance between the two points in meters by assuming that the Earth is a perfectly round sphere with a radius of 6,371,008 meters. (Note that the Earth isn’t actually a perfect sphere; its radius at the poles is about 21 meters shorter than its radius at the equator. This will result in very slight inaccuracies in our calculations.)

In the second, we convert from meters to miles, yards, feet, and kilometers so that you can get your distance in whatever units are needed.

Here they are:

function get_meters_between_points($latitude1,$longitude1,$latitude2,$longitude2) 
{
    if (($latitude1 == $latitude2) && ($longitude1 == $longitude2)){
        return 0; 
    } // distance is zero because they're the same point

    $p1 = deg2rad($latitude1);
    $p2 = deg2rad($latitude2);

    $dp = deg2rad($latitude2 - $latitude1);
    $dl = deg2rad($longitude2 - $longitude1);

    $a = (sin($dp/2) * sin($dp/2)) + (cos($p1) * cos($p2) * sin($dl/2) * sin($dl/2));
    $c = 2 * atan2(sqrt($a),sqrt(1-$a));
    $r = 6371008; // Earth's average radius, in meters
    $d = $r * $c;

    return $d; // distance, in meters
}

function get_distance_between_points($latitude1, $longitude1, $latitude2, $longitude2) 
{
    $meters = get_meters_between_points($latitude1, $longitude1, $latitude2, $longitude2);
    $kilometers = $meters / 1000;
    $miles = $meters / 1609.34;
    $yards = $miles * 1760;
    $feet = $miles * 5280;
    return compact('miles','feet','yards','kilometers','meters');
}

Here’s an example of the function in action, using two coordinates in New York City:

$point1 = array(40.713008, -74.013169);
$point2 = array(40.829643, -73.926175);
$distance = get_distance_between_points($point1['0'], $point1['1'], 
$point2['0'], $point2['1']);
echo '<p>The two points are '.round($distance['miles'],2).' miles apart.</p>';