地圖根據多個坐標點,計算中心點坐標

地圖根據多個坐標點,計算中心點坐標

參考文檔

//參數數組points的每一項為每一個點的：緯度,經度
//如 points = ['30.86660,104.390740', '30.861961,104.386963', '30.842287,104.388079', '點的緯度,點的經度'……];
//返回中心點的數組[緯度,精度]
getPointsCenter(points) {
    var point_num = points.length; //坐標點個數
    var X = 0, Y = 0, Z = 0;
    for(let i = 0; i< points.length; i++) {
      if (points[i] == '') {
        continue;
      }
      let point = points[i].split(',');
      var lat, lng, x, y, z;
      lat = parseFloat(point[0]) * Math.PI / 180;
      lng = parseFloat(point[1]) * Math.PI / 180;
      x = Math.cos(lat) * Math.cos(lng);
      y = Math.cos(lat) * Math.sin(lng);
      z = Math.sin(lat);
      X += x;
      Y += y;
      Z += z;
    }
    X = X / point_num;
    Y = Y / point_num;
    Z = Z / point_num;

    var tmp_lng = Math.atan2(Y, X);
    var tmp_lat = Math.atan2(Z, Math.sqrt(X * X + Y * Y));

    return [tmp_lat * 180 / Math.PI, tmp_lng * 180 / Math.PI];
}

// 例如我的格式是：緯度1,經度1;緯度2,經度2;……
var str = "30.866603259732102,104.39074045163579;30.8619616865538,104.38696390134282;30.842287763333733,104.38807970029302;30.843761605258894,104.43202501279302;30.851572589486928,104.43545824033208;30.874265047548715,104.41202646237798";
var arr = str.split(';');
var tmp_center = this.getPointsCenter(arr);
 
//總之返回的tmp_center[0]就是緯度，tmp_center[1]就是經度
 
//如果是騰訊地圖如下：
//var default_point = new qq.maps.LatLng(tmp_center[0], tmp_center[1]);
//this.map.setCenter(default_point);