Get distance in Km between two lat lan address using Google Maps API

Question

When running this code it did not give any value. But when replace lat lan value with (37.910689 ,-97.250977),(16.110560, -94.174805) then it returns result in meters. It shows blank output when passed any other lat lan value then the USA address.

function location(){

    $url="https://maps.googleapis.com/maps/api/distancematrix/json?units=metric&origins=28.666585,-77.229059&destinations=28.667053%2C-77.219898&key=Api key";

    $json_string = $url; 
    $jsondata = file_get_contents($json_string);
    $obj = json_decode($jsondata, TRUE); // Set second argument as TRUE

    //print_r($obj['rows']); // Now this will works!
    $prn=$obj['rows'];  
    foreach($prn as $row)
    { 
        $ele=$row['elements'];
        foreach($ele as $k)
        { 
            $dis=$k['distance'];
            foreach($dis as $l=> $lvalue){
                $meter= $lvalue  ;
            }
        }
    }   

    return $meter ;
}

Answer 1

The two points you specified in your code are in the Atlantic ocean. You can verify by entering 28.667053,-77.219898 in search box at https://www.google.com. Google responds with ZERO_RESULTS, because it cannot calculate the distance between 2 points in ocean.

UPDATE: Note that what the google map api gives you is NOT the aerial or the shortest distance between 2 points or "as the crow flies" distance. It is the driving distance or walking distance. So it has to know about the 2 points before it can give you a distance. If it does not know the 2 points or cannot calculate the route to the 2 points it will not give results. https://maps.googleapis.com/maps/api/distancematrix/json?units=metric&origins=20.254916,76.715059&destinations=20.3127202,76.6839331 - these points are close but driving / walking distance is large. Goole maps gives the driving / walking distance.

{
"destination_addresses": [
"28.667053,-77.219898"
],
"origin_addresses": [
"28.666585,-77.229059"
],
"rows": [
{
"elements": [
{
"status": "ZERO_RESULTS"
}
]
}
],
"status": "OK"
}

Google responds with correct distance for 2 points within US e.g https://maps.googleapis.com/maps/api/distancematrix/json?units=metric&origins=42.025819,-88.0854497&destinations=41.910088,-87.6929887