如何创建多段线上的标记，与多段线上的另一个标记相距一定距离 - GoogleMaps API Javascript V3 [英] How to create a marker that would be on a polyline, at a certain distance from another marker on the polyline- GoogleMaps API Javascript V3

问题描述

我试图在已经创建的折线上的起始点的某个距离处添加一个标记。
（我有一个多段线，起点和终点在这些点上有标记。我想在距离起始点特定距离处添加标记。我尝试使用方法poly.GetPointsAtDistance（distance），但显然它是我已经看过不同的帖子和谷歌地图Api，但没有成功使它的工作。
我有

I am trying to add a marker at a certain distance form the starting point on the polyline I already created. (I have a polyline with start point and end point with markers at those points.I want to add markers at specific distances from the start point. I tried to use the method poly.GetPointsAtDistance(distance) but apparently it is not in use anymore. I have looked at different posts and google Maps Api but haven't succeeded to make it work. I have

 var line = new google.maps.Polyline({
 map: map, 
 path: [location1, location2],
 strokeWeight: 7,
 strokeOpacity: 0.8,
 strokeColor: "#FFAA00"
});

折线的长度

 var line_length = google.maps.geometry.spherical.computeLength(line.getPath());)

我有一个函数来创建标记：

I have a function to create the marker:

 function createMarker(map, latlng, title){
 var marker = new google.maps.Marker({
    position:latlng,
    map:map,
      title: title
      });

我希望能够通过给出距离（new_distance）从起点创建标记。
类似于：

I would like to be able to create the marker by giving the distance (new_distance) From start point. In something like:

createMarker(map, line.GetPointAtDistance(new_distance), title);

任何有关如何取代GetPointAtDistance的建议

Any suggestion to what to use to replace GetPointAtDistance

推荐答案

函数.GetPointAtDistance是Mike Williams的用于v2的epoly库。这里有一个版本移植到v3：
http://www.geocodezip.com/ scripts / v3_epoly.js

The function .GetPointAtDistance is part of Mike Williams' epoly library for v2. There is a version ported to v3 here: http://www.geocodezip.com/scripts/v3_epoly.js

例子在v3上使用它

代码：

// === A method which returns a google.maps.LatLng of a point a given distance along the path ===
// === Returns null if the path is shorter than the specified distance ===
google.maps.Polyline.prototype.GetPointAtDistance = function(metres) {
  // some awkward special cases
  if (metres == 0) return this.getPath().getAt(0);
  if (metres < 0) return null;
  if (this.getPath().getLength() < 2) return null;
  var dist=0;
  var olddist=0;
  for (var i=1; (i < this.getPath().getLength() && dist < metres); i++) {
    olddist = dist;
    dist += google.maps.geometry.spherical.computeDistanceBetween(
              this.getPath().getAt(i),
              this.getPath().getAt(i-1)
            );
  }
  if (dist < metres) {
    return null;
  }
  var p1= this.getPath().getAt(i-2);
  var p2= this.getPath().getAt(i-1);
  var m = (metres-olddist)/(dist-olddist);
  return new google.maps.LatLng( p1.lat() + (p2.lat()-p1.lat())*m, p1.lng() + (p2.lng()-p1.lng())*m);
}

需要 google.maps.geometry库。

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