JavaScript实现计算多边形质心的方法示例

function Area(p0,p1,p2){  var area = 0.0 ;  area = p0.lng * p1.lat + p1.lng * p2.lat + p2.lng * p0.lat - p1.lng * p0.lat - p2.lng * p1.lat - p0.lng * p2.lat;  return area / 2 ;}//line 249 计算polygon的质心function getPolygonAreaCenter(points) {  var sum_x = 0;  var sum_y = 0;  var sum_area = 0;  var p1 = points[1];  debugger;  for (var i = 2; i < points.length; i++) {    p2=points[i];    area = Area(points[0],p1,p2) ;    sum_area += area ;    sum_x += (points[0].lng + p1.lng + p2.lng) * area;    sum_y += (points[0].lat + p1.lat + p2.lat) * area;    p1 = p2 ;  }  var xx = sum_x / sum_area / 3;  var yy = sum_y / sum_area / 3;  return new BMap.Point(xx, yy);}