如何获取当前用户的经纬度并计算与位置 B 的距离？

Question

我可以知道如何获取当前用户位置并计算位置 B 之间的距离（以公里为单位）吗？

我尝试了下面的代码，但似乎不起作用。

<?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);

    }

    ?>

如何在 $point1 = array("lat" => $latitude, "long" => $longitude);以便我可以计算用户位置和位置 B 之间的距离？

请帮忙。谢谢。

Answer 1

Eddy 目前您正计划将 javascript 变量分配给 PHP 变量，这不是做事的正确方法，因为一个在客户端，另一个在服务器端。 Reference.

我已更改您的代码以查找用户位置与商家位置之间的距离。

<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>

在上面的代码中，您会将数据库值传递给merch_longitude 和merch_latitude，目前它是硬编码的。我们将使用 Javascript 的地理位置获取用户的当前位置，然后showPosition() 将计算距离。

距离函数有 5 个参数 lat1, long1, lat2, long2, unit。

默认单位是Miles，K表示KM，N表示NM。