Question

嗨，我正在通过将Javascript与地理位置结合使用来创建步行跟踪器网络应用。除了必须使用旧的latlong和新的latlong来计算距离的那部分以外，其他所有东西都工作正常。

代码：

function updateLocation(position) {
   var latitude = position.coords.latitude;
   var longitude = position.coords.longitude;
   var accuracy = position.coords.accuracy;
   var timestamp = position.timestamp;

   document.getElementById("latitude").innerHTML = latitude;
   document.getElementById("longitude").innerHTML = longitude;
   document.getElementById("accuracy").innerHTML = accuracy.toFixed(2) + " meter";
   document.getElementById("timestamp").innerHTML = new Date(timestamp).toLocaleString();


   if (accuracy >= 500) {
     updateStatus("Need more accurate values to calculate distance.");
     return;
   }

   if ((lastLat != null) && (lastLong != null)) {
     var currentDistance = distance(latitude, longitude, lastLat, lastLong);
     document.getElementById("currDist").innerHTML =
       "Current distance traveled: " + currentDistance.toFixed(2) + " km";

     totalDistance += currentDistance;

     document.getElementById("totalDist").innerHTML =
       "Total distance traveled: " + currentDistance.toFixed(2) + " km";
   }


   lastLat = latitude;
   lastLong = longitude;

   updateStatus("Location successfully updated.");
}

添加了距离功能*

Number.prototype.toRadians = function() {
return this * Math.PI / 180;

}

function distance(latitude1, longitude1, latitude2, longitude2) {
// R is the radius of the earth in kilometers
var R = 6371;

var deltaLatitude = (latitude2-latitude1).toRadians();
var deltaLongitude = (longitude2-longitude1).toRadians();
latitude1 = latitude1.toRadians(), latitude2 = latitude2.toRadians();

var a = Math.sin(deltaLatitude/2) *
        Math.sin(deltaLatitude/2) +
        Math.cos(latitude1) *
        Math.cos(latitude2) *
        Math.sin(deltaLongitude/2) *
        Math.sin(deltaLongitude/2);

var c = 2 * Math.atan2(Math.sqrt(a),
                       Math.sqrt(1-a));
var d = R * c;
return d;

}

希望有人能发现我做错了什么。谢谢

更新：

我发现了为什么地理位置不能更新我的距离的问题..因为我声明的变量 lastlong 和 lastlat 没有给我以前的位置，它为我提供了纬度和经度的当前位置，这些位置是我在updateLocation中声明的，并为这些变量分配了lastlat和last long。

我的问题是现在我该如何使用新位置，找不到任何解决方案。

新更新：

找到了解决此问题的方法。用于计算先前距离我将坐标存储在数组中并获得最后的位置计算当前位置的距离。

代码：

 var coords = []; var distance = 0.0;



function calculateDistance(fromPos, toPos) {
    var radius = 6371;
    var toRad = function(number) {
        return number * Math.PI / 180;
    };

    var latDistance = toRad(toPos.latitude - fromPos.latitude);
    var lonDistance = toRad(toPos.longitude - fromPos.longitude);
    var a = Math.sin(latDistance / 2) * Math.sin(latDistance / 2) + 
            Math.cos(toRad(fromPos.latitude)) * Math.cos(toRad(toPos.latitude)) * 
            Math.sin(lonDistance / 2) * Math.sin(lonDistance / 2);

    return radius * (2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a))); 
}


var lastPos = coords[coords.length-1];
    if(lastPos) {

        distance += calculateDistance(lastPos, position.coords);
        document.getElementById("currDist").innerHTML =
    "Current distance traveled: " + distance.toFixed(2) + " km";
    }


    coords.push(position.coords);

我不明白的一件事是为什么数组中的时间戳未定义？因为经久耐用，我可以轻松自在地生活。

Answer 1

有关完整的工作旅程记录器示例，请参见Google Drive或GitHub。

请注意TravelManagerPolyfil.js中的filterLocation函数，因为您可能只是获得许多零距离读数，并且需要限制watchPosition。

此代码有效：-

<!DOCTYPE html>
<html>
<body>

<p>Click the button to get your coordinates.</p>

<button onclick="getLocation()">Try It</button>

<p id="demo"></p>

<script>
    var perthLat = 31.9505;
    var perthLon = 115.8605;
    var freoLat = 32.0569;
    var freoLon = 115.7439;
    const EARTH_RADIUS = 6378137; 
    var toRad = 
        function (num) {
            return num * Math.PI / 180;
        };  
    var calculateDistance =
        function(lat1, lon1, lat2, lon2){
            var dLat = toRad(lat2 - lat1);
            var dLon = toRad(lon2 - lon1);
            var a = Math.sin(dLat / 2) * Math.sin(dLat / 2) + Math.cos(this.toRad(lat1)) * 
                    Math.cos(toRad(lat2)) * Math.sin(dLon / 2) * Math.sin(dLon / 2);
            var distance = EARTH_RADIUS * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
            return distance;
        }

var x = document.getElementById("demo");

function getLocation() {
    if (navigator.geolocation) {
        navigator.geolocation.getCurrentPosition(showPosition);
    } else { 
        x.innerHTML = "Geolocation is not supported by this browser.";
    }
}

function showPosition(position) {
    x.innerHTML = "Distance = " + 
        calculateDistance(perthLat, perthLon,
                          freoLat, freoLon) / 1000;
}
</script>

</body>
</html>

地理位置不会更新我的步行距离

1 个答案: