php - Get driving distance between two points using Google Maps API

Question

I'm trying to get driving distance between two points using Google Maps API. Now, I have code which get direct distance:

This function get lat and lng:

function get_coordinates($city, $street, $province)
{
    $address = urlencode($city.','.$street.','.$province);
    $url = "http://maps.google.com/maps/api/geocode/json?address=$address&sensor=false&region=Poland";
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_PROXYPORT, 3128);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    $response = curl_exec($ch);
    curl_close($ch);
    $response_a = json_decode($response);
    $return = array('lat' => $response_a->results[0]->geometry->location->lat, 'long' => $long = $response_a->results[0]->geometry->location->lng);

    return $return;
}

This function calculate distance between two points based on lat & lng:

function getDistanceBetweenPoints($lat1, $lon1, $lat2, $lon2) {
    $theta = $lon1 - $lon2;
    $miles = (sin(deg2rad($lat1)) * sin(deg2rad($lat2))) + (cos(deg2rad($lat1)) * cos(deg2rad($lat2)) * cos(deg2rad($theta)));
    $miles = acos($miles);
    $miles = rad2deg($miles);
    $miles = $miles * 60 * 1.1515;
    $kilometers = $miles * 1.609344;
    return $kilometers;
}

This function print distance by kilometers:

function get_distance($lat1, $lat2, $long1, $long2)
{
    /* These are two points in New York City */
    $point1 = array('lat' => $lat1, 'long' => $long1);
    $point2 = array('lat' => $lat2, 'long' => $long2);

    $distance = getDistanceBetweenPoints($point1['lat'], $point1['long'], $point2['lat'], $point2['long']);
    return $distance;
}

Usage:

$coordinates1 = get_coordinates('Katowice', 'Korfantego', 'Katowicki');
$coordinates2 = get_coordinates('Tychy', 'Jana Paw?a II', 'Tyski');

echo 'Distance: <b>'.round(get_distance($coordinates1['lat'], $coordinates2['lat'], $coordinates1['long'], $coordinates2['long']), 1).'</b> km';

But this code get direct distance. I need driving distance. How I can get driving distance using google maps API?

Thanks for your help!

Answer 1

OK, I found solution using distance matrix: https://developers.google.com/maps/documentation/distancematrix/#DistanceMatrixRequests

This function get lat & lng from city, adress, province:

function get_coordinates($city, $street, $province)
{
    $address = urlencode($city.','.$street.','.$province);
    $url = "http://maps.google.com/maps/api/geocode/json?address=$address&sensor=false&region=Poland";
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_PROXYPORT, 3128);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    $response = curl_exec($ch);
    curl_close($ch);
    $response_a = json_decode($response);
    $status = $response_a->status;

    if ( $status == 'ZERO_RESULTS' )
    {
        return FALSE;
    }
    else
    {
        $return = array('lat' => $response_a->results[0]->geometry->location->lat, 'long' => $long = $response_a->results[0]->geometry->location->lng);
        return $return;
    }
}

This function calculate driving distance and travel time duration:

function GetDrivingDistance($lat1, $lat2, $long1, $long2)
{
    $url = "https://maps.googleapis.com/maps/api/distancematrix/json?origins=".$lat1.",".$long1."&destinations=".$lat2.",".$long2."&mode=driving&language=pl-PL";
    $ch = curl_init();
    curl_setopt($ch, CURLOPT_URL, $url);
    curl_setopt($ch, CURLOPT_RETURNTRANSFER, 1);
    curl_setopt($ch, CURLOPT_PROXYPORT, 3128);
    curl_setopt($ch, CURLOPT_SSL_VERIFYHOST, 0);
    curl_setopt($ch, CURLOPT_SSL_VERIFYPEER, 0);
    $response = curl_exec($ch);
    curl_close($ch);
    $response_a = json_decode($response, true);
    $dist = $response_a['rows'][0]['elements'][0]['distance']['text'];
    $time = $response_a['rows'][0]['elements'][0]['duration']['text'];

    return array('distance' => $dist, 'time' => $time);
}

Usage:

$coordinates1 = get_coordinates('Tychy', 'Jana Paw?a II', '?l?skie');
$coordinates2 = get_coordinates('L?dziny', 'L?dzińska', '?l?skie');
if ( !$coordinates1 || !$coordinates2 )
{
    echo 'Bad address.';
}
else
{
    $dist = GetDrivingDistance($coordinates1['lat'], $coordinates2['lat'], $coordinates1['long'], $coordinates2['long']);
    echo 'Distance: <b>'.$dist['distance'].'</b><br>Travel time duration: <b>'.$dist['time'].'</b>';
}

Return:

Distance: 11,2 km Travel time duration: 15 min