google-maps - 检查点是否在多边形( map )中

Question

我正在尝试检查一个点是否在多边形中。
目前我已尝试使用此功能

pointInPolygon:function (point,polygon){
    var i;
    var j=polygon.length-1;
    var inPoly=false;
    var lon = point.longitude;
    var lat = point.latitude;
    for (i=0; i<polygon.length; i++)
    {
        if (polygon[i][0]<lon && polygon[j][0]>=lon|| polygon[j][0]<lon && polygon[i][0]>=lon){
            if (polygon[i][0]+(lon-polygon[i][0])/(polygon[j][0]-polygon[i][0])*(polygon[j][1]-polygon[i][1])<lat){
                inPoly=!inPoly;
            }
        }
        j=i;
    }
    return inPoly;
}

...此功能似乎适用于简单的多边形( http://jsfiddle.net/zTmr7/3/ )，但对我不起作用...
这是多边形的示例数据:

polygon: Array[14]
Array[2]
        0: "-120.190625"
        1: "29.6614549946937"
Array[2]
        0: "-116.87275390625"
        1: "32.6320990313992"
Array[2]
        0: "-116.60908203125"
        1: "34.0363970332393"
Array[2]
        0: "-120.89375"
        1: "41.9203747676428"
Array[2]
        0: "-114.74140625"
        1: "45.784484644005"
Array[2]
        0: "-115.971875"
        1: "48.6489780115889"
Array[2]
        0: "-132.758984375"
        1: "59.9891712248332"
Array[2]
        0: "-162.5099609375"
        1: "68.919753529737"
Array[2]
        0: "-168.6623046875"
        1: "68.9828872543805"
Array[2]
        0: "-168.4865234375"
        1: "64.2551601036027"
Array[2]
        0: "-179.874356794357"
        1: "51.0915874974707"
Array[2]
        0: "-179.999916362762"
        1: "13.1823178795562"
Array[2]
        0: "-143.8771484375"
        1: "19.9962034117847"
Array[2]
        0: "-120.190625"
        1: "29.6614549946937"  

也许你可以帮忙......提前致谢

附注。解决方案必须特别适用于 Bing map 或通用解决方案...

Answer 1

Google map API 尚未提供检查多边形中的点的方法。经过一番研究后，我偶然发现了光线转换算法，该算法将确定 X-Y​​ 坐标是否在绘制的形状内。这将转换为纬度和经度。以下扩展了 google.maps.polygon.prototype 以使用此算法。加载 google.maps 后，只需在代码中的某个点包含此代码:

google.maps.Polygon.prototype.Contains = function(point) {
  var crossings = 0, path = this.getPath();

  // for each edge
  for (var i=0; i < path.getLength(); i++) {
      var a = path.getAt(i),
          j = i + 1;
      if (j >= path.getLength()) {
          j = 0;
      }
      var b = path.getAt(j);
      if (rayCrossesSegment(point, a, b)) {
        crossings++;
      }
  }

  // odd number of crossings?
  return (crossings % 2 == 1);

  function rayCrossesSegment(point, a, b) {
    var px = point.lng(),
        py = point.lat(),
        ax = a.lng(),
        ay = a.lat(),
        bx = b.lng(),
        by = b.lat();
    if (ay > by) {
        ax = b.lng();
        ay = b.lat();
        bx = a.lng();
        by = a.lat();
    }
    // alter longitude to cater for 180 degree crossings
    if (px < 0) { px += 360 };
    if (ax < 0) { ax += 360 };
    if (bx < 0) { bx += 360 };

    if (py == ay || py == by) py += 0.00000001;
    if ((py > by || py < ay) || (px > Math.max(ax, bx))) return false;
    if (px < Math.min(ax, bx)) return true;

    var red = (ax != bx) ? ((by - ay) / (bx - ax)) : Infinity;
    var blue = (ax != px) ? ((py - ay) / (px - ax)) : Infinity;
    return (blue >= red);
  }
};

在这里，我们通过定义一个名为“Contains”的函数来扩展 google.maps.Polygon 的功能，该函数可用于确定函数参数中提供的纬度经度是否在多边形内。在这里，我们使用了 Ray-casting 算法并开发了一个使用它的函数。现在做了这么多练习之后，我们可以检查一个点如下:

var point = new google.maps.LatLng(52.05249047600099, -0.6097412109375); varpolygon = new google.maps.Polygon({path:[INSERT_PATH_ARRAY_HERE]}); if (polygon.Contains(point)) {//点在多边形内 }

完整代码和演示请到: http://counsellingbyabhi.blogspot.in/2013/01/google-map-check-whether-point-latlong.html