谷歌地图圈到多段线坐标数组 [英] google maps circle to polyline coordinate array

问题描述

如何从 google.maps.Circle 的对象获取多段线坐标数组
$ b

解决方案

google.maps.Circle不包含坐标数组。如果你想要一个圆形的google.maps.Polygon，你需要创建一个。

 函数drawCircle（point ，radius，dir）{
 var d2r = Math.PI / 180; //度数为弧度
 var r2d = 180 / Math.PI; //弧度到度
 var earthsradius = 3963; // 3963是以英里为单位的地球半径
 
 var points = 32; 
 
 //找到lat / lon中的raidus 
 var rlat =（radius / earthsradius）* r2d; 
 var rlng = rlat / Math.cos（point.lat（）* d2r）; 
 
 var extp = new Array（）; 
 if（dir == 1）{
 var start = 0; 
 var end = points + 1; //这里另外一个确保我们连接路径
} else {
 var start = points + 1; 
 var end = 0; 
 
 for（var i = start;（dir == 1？i< end：i> end）; i = i + dir）
 {
 var theta = Math.PI *（i /（points / 2））; 
 ey = point.lng（）+（rlng * Math.cos（theta））; //中心a +半径x * cos（theta）
 ex = point.lat（）+（rlat * Math.sin（theta））; // center b + radius y * sin（theta）
 extp.push（new google.maps.LatLng（ex，ey））; 
} 
 return extp; 
} 
 
 var circle = new google.maps.Polygon（{
 map：map，
 paths：[drawCircle（new google.maps.LatLng（-33.9 ，151.2），100,1）]，
 strokeColor：＃0000FF，
 strokeOpacity：0.8，
 strokeWeight：2，
 fillColor：＃FF0000，
 fillOpacity：0.35 
}）; 
  

例子

how to get array of polyline coordinates from google.maps.Circle's object

there is no api doc entry about that

解决方案

A google.maps.Circle doesn't contain an array of coordinates. If you want a google.maps.Polygon that is shaped like a circle, you need to make one.

function drawCircle(point, radius, dir) { 
  var d2r = Math.PI / 180;   // degrees to radians 
  var r2d = 180 / Math.PI;   // radians to degrees 
  var earthsradius = 3963; // 3963 is the radius of the earth in miles

  var points = 32; 

  // find the raidus in lat/lon 
  var rlat = (radius / earthsradius) * r2d; 
  var rlng = rlat / Math.cos(point.lat() * d2r); 

  var extp = new Array(); 
  if (dir==1) {
     var start=0;
     var end=points+1; // one extra here makes sure we connect the path
  } else {
     var start=points+1;
     var end=0;
  }
  for (var i=start; (dir==1 ? i < end : i > end); i=i+dir)  
  { 
     var theta = Math.PI * (i / (points/2)); 
     ey = point.lng() + (rlng * Math.cos(theta)); // center a + radius x * cos(theta) 
     ex = point.lat() + (rlat * Math.sin(theta)); // center b + radius y * sin(theta) 
     extp.push(new google.maps.LatLng(ex, ey)); 
  } 
  return extp;
}

var circle = new google.maps.Polygon({
               map: map,
               paths: [drawCircle(new google.maps.LatLng(-33.9,151.2), 100, 1)],
               strokeColor: "#0000FF",
               strokeOpacity: 0.8,
               strokeWeight: 2,
               fillColor: "#FF0000",
               fillOpacity: 0.35
});

Example

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