How to get current user latitude and longitude and calculate distance with location B?

Question

May I know how to get current user location and calculate distance between location B in kilometer?

I tried below codes but seems like does not work.

<?php               
echo "<script type = 'text/javascript'>
function showPosition(){
    if(navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(function(position){
            var latitude = position.coords.latitude;
            var longitude = position.coords.longitude; 
        });
    } else {
        alert(\"Sorry, your browser does not support HTML5 geolocation.\");
    }
}
</script>";

$point1 = array("lat" => $latitude, "long" => $longitude); 
$point2 = array("lat" => $row_Merchant['latitude'], "long" => $row_Merchant['longitude']); 
$km = distanceCalculation($point1['lat'], $point1['long'], $point2['lat'], $point2['long']); // Calculate distance in kilometres (default)
echo "$km km";
?>


    <?php

    function distanceCalculation($point1_lat, $point1_long, $point2_lat, $point2_long, $unit = 'km', $decimals = 2)
    {
    // Calculate the distance in degrees

    $degrees = rad2deg(acos((sin(deg2rad($point1_lat)) * sin(deg2rad($point2_lat))) + (cos(deg2rad($point1_lat)) * cos(deg2rad($point2_lat)) * cos(deg2rad($point1_long - $point2_long)))));


    // Convert the distance in degrees to the chosen unit (kilometres, miles or nautical miles)

    switch ($unit) {

    case 'km':

    $distance = $degrees * 111.13384; // 1 degree = 111.13384 km, based on the average diameter of the Earth (12,735 km)

    break;

    case 'mi':

    $distance = $degrees * 69.05482; // 1 degree = 69.05482 miles, based on the average diameter of the Earth (7,913.1 miles)

    break;

    case 'nmi':

    $distance =  $degrees * 59.97662; // 1 degree = 59.97662 nautic miles, based on the average diameter of the Earth (6,876.3 nautical miles)

    }

    return round($distance, $decimals);

    }

    ?>

How can I pass in value latitude and longitude in $point1 = array("lat" => $latitude, "long" => $longitude); so that I can calculate distance between user location and lcoation B?

Please help. Thank you.

Please provide more detail.. what do you mean by does not work? you are getting any error? and also paste code of `distanceCalculation()` . — Touheed Khan, May 21 '19 at 03:07
@TouheedKhan, please find updated code as above for your information. Invalid distance KM will show if using above code. — AD Tee, May 21 '19 at 03:23

Touheed Khan · Accepted Answer · 2019-11-29T08:31:25.607

Eddy currently you're planning to assign javascript variable to PHP variable which is not the right way to do things as one in Client-side and other is Server-side. Reference.

I have changed your code to find distance between user's location and merchant's location.

<script type = 'text/javascript'>
    function distance(lat1, lon1, lat2, lon2, unit) {
            var radlat1 = Math.PI * lat1/180;
            var radlat2 = Math.PI * lat2/180;
            var radlon1 = Math.PI * lon1/180;
            var radlon2 = Math.PI * lon2/180;
            var theta = lon1-lon2;
            var radtheta = Math.PI * theta/180;
            var dist = Math.sin(radlat1) * Math.sin(radlat2) + Math.cos(radlat1) * Math.cos(radlat2) * Math.cos(radtheta);
            dist = Math.acos(dist);
            dist = dist * 180/Math.PI;
            dist = dist * 60 * 1.1515;
            if (unit=="K") { dist = dist * 1.609344; }
            if (unit=="N") { dist = dist * 0.8684; }
            return dist;
    }

    function showPosition(dest_lon, dest_lat){
        if(navigator.geolocation) {
            console.log('hhhh');
            navigator.geolocation.getCurrentPosition(function(position){
                latitude = position.coords.latitude;
                longitude = position.coords.longitude; 
                console.log(latitude+','+longitude+','+ dest_lat+','+ dest_lon);
                dist = distance(latitude, longitude, dest_lat, dest_lon, 'K');
                console.log(dist);  //final distance present in dist variable          
            });
        } else {
            alert("Sorry, your browser does not support HTML5 geolocation.");
        }
    }

    var merch_longitude = 47.683277;
    var merch_latitude = 3.210482;
    showPosition(merch_longitude, merch_longitude);
</script>

In above code you'll pass database value to merch_longitude and merch_latitude currently it is hard coded. We will get current location of user using geolocation of Javascript, then showPosition() will calculate distance.

Distance function takes 5 parameter lat1, long1, lat2, long2, unit.

By default unit is Miles, you can pass K for KM and N for NM.

How to get current user latitude and longitude and calculate distance with location B?

1 Answers1