Question

我已经尝试这样做了几天但还没到任何地方。

这适用于使用Phonegap Build构建的混合应用程序。

我正在尝试使用我的地理定位应用来计算出行进的距离。到目前为止，我已经拥有了它，所以它返回A和B之间的值，但我需要它来解决当前位置更新（观察位置）所以它反复迭代，所以如果我进行了10次循环它就不会＃39 ; t只是圆的半径。

这是我到目前为止所拥有的...... 请原谅代码，我对Javascript相对较新，并且很难理解参数并完全返回。

 Starting Latitude: <span id="starting_lat">0</span><br>
 Starting Longitude: <span id="starting_long">0</span><br>
 Current Latitude: <span id="current_lat">0</span><br>
 Current Longitude: <span id="current_long">0</span><br>
 Speed: <span id="speed">0</span><br>
 My Distance: <span id="myDistance">0</span><br>


 <script>

 var startingLat;
 var startingLong;
 var currentLat;
 var currentLong;


 startApp(); //Start the Application


 function startApp() {

 getStartingPosition(); //Get my starting position
 startTracking(); // Start watching the location


 }



 function getStartingPosition(){


 var getStartingLocation = function(position) {

 startingLat=position.coords.latitude; 
 startingLong=position.coords.longitude;
 document.getElementById('starting_lat').innerHTML=(startingLat);
 document.getElementById('starting_long').innerHTML=(startingLong);

 };

 // onError Callback receives a PositionError object
 //
 function displayError(frror) {
 alert('code: '    + frror.code    + '\n' +
  'message: ' + frror.message + '\n');
 }

 navigator.geolocation.getCurrentPosition(getStartingLocation, displayError);


 }





 function startTracking(){


function onSuccess(position) {

 currentLat=position.coords.latitude;
 currentLong=position.coords.longitude;
 document.getElementById('current_lat').innerHTML=(currentLat);
 document.getElementById('current_long').innerHTML=(currentLong);


 getDistance()

 }




 function onError(error) {

 alert('code: '    + error.code    + '\n' +
 'message: ' + error.message + '\n');
 }




 // Options: throw an error if no update is received every 30 seconds.
 //
 var watchID = navigator.geolocation.watchPosition(onSuccess, onError, {      timeout: 30000 });


 }



 // Take the starting longitude and  latitude, along with current latitude and longitude to work out the distance and output it to the myDistance div.


 function getDistance(){

  var lat1 = startingLat;
  var lon1 = startingLong;
  var lat2 = currentLat;
  var lon2 = currentLong;

 var R = 6371; // Radius of the earth in km
 var dLat = deg2rad(lat2-lat1);  // deg2rad below
 var dLon = deg2rad(lon2-lon1); 
 var a = 
 Math.sin(dLat/2) * Math.sin(dLat/2) +
 Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * 
 Math.sin(dLon/2) * Math.sin(dLon/2)
 ; 
 var c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1-a)); 
 var d = R * c; // Distance in km

 d=d.toFixed(2);


 document.getElementById('myDistance').innerHTML=(d); 



 function deg2rad(deg) {
 return deg * (Math.PI/180)
 }



 }



 </script>

我尝试在这里使用另一个例子来添加一个数组的距离，但结构与我所做的略有不同，所以我发现它令人困惑。任何人都可以推荐一种简单的方法来应用迭代距离的数组吗？

再次提一下，这是针对使用Phonegap Build的移动应用程序。

谢谢。

Answer 1

This page by Movable Type包含地理空间计算的公式，更好的是，大多数公式已经written in Javascript。

所以使用他们的库和你的例子，我会做这样的事情：

Starting Latitude: <span id="starting_lat">0</span><br>
Starting Longitude: <span id="starting_long">0</span><br>
Current Latitude: <span id="current_lat">0</span><br>
Current Longitude: <span id="current_long">0</span><br>
Speed: <span id="speed">0</span><br>
Direct Distance (km): <span id="directDistance">0</span><br>
Cumulative Distance (km): <span id="cumulativeDistance">0</span><br>


<script>
    var startPos;
    var prevPos;
    var currentPos;
    var watchID;
    var cumulativeDist = 0;

    document.addEventListener("deviceready", startApp, false); //Start the Application


    function startApp() {
      // Start watching the location
      watchID = navigator.geolocation.watchPosition(onSuccess, onError, {timeout: 30000, maxAge:0, enableHighAccuracy: false }); // enableHighAccuracy=false => No GPS
    }


    function onSuccess(position) {

      if(currentPos){
        prevPos = currentPos;
      )

      currentPos = new LatLon(position.coords.latitude, position.coords.longitude);
      document.getElementById('current_lat').innerHTML=(currentPos.lat());
      document.getElementById('current_long').innerHTML=(currentPos.lon());

      if(!startPos){
        startPos = currentPos;
        document.getElementById('starting_lat').innerHTML=(startPos.lat());
        document.getElementById('starting_long').innerHTML=(startPos.lon())
      }

      if(prevPos){
        getDistance();
      }
    }


    function onError(error) {
      alert('code: '    + error.code    + '\n' +
        'message: ' + error.message + '\n');
    }


    function getDistance(){

      cumulativeDist += currentPos.distanceTo(prevPos);
      document.getElementById('cumulativeDistance').innerHTML=(cumulativeDist);

      var directDist = currentPos.distanceTo(startPos);
      document.getElementById('directDistance').innerHTML=(directDist);
    }
</script>

使用数组的地理定位总距离

1 个答案: