var polygon = layerMan.NewPolygon(1000, 1);
    polygon.BeginUpdate();
    polygon.AddPoint(centerLL._X + 100, centerLL._Y + 100);
    polygon.AddPoint(centerLL._X + 100, centerLL._Y + 500);
    polygon.AddPoint(centerLL._X + 500, centerLL._Y + 500);
    polygon.AddPoint(centerLL._X + 500, centerLL._Y + 100);

    polygon.SetClosed(1);   // 0: PolyLine, 1: Polygon
    polygon.SetStyle(style);
    polygon.EndUpdate();
    alert(polygon.GetArea()); 

준비중입니다...