計算坐標中心點

 

計算給定的坐標的中心點坐標

private QueryEntity getCentPoint(List<QueryEntity> pointlist){
        int total = pointlist.size();  
        double X = 0, Y = 0, Z = 0;  
        for (QueryEntity g : pointlist)  
        {  
            double lat, lon, x, y, z;  
            lat = (Double.parseDouble(g.getY())) * Math.PI / 180;  //緯度
            lon = (Double.parseDouble(g.getX())) * Math.PI / 180;  //經度
            x = Math.cos(lat) * Math.cos(lon);  
            y = Math.cos(lat) * Math.sin(lon);  
            z = Math.sin(lat);  
            X += x;  
            Y += y;  
            Z += z;  
        }  
        X = X / total;  
        Y = Y / total;  
        Z = Z / total;  
        double Lon = Math.atan2(Y, X);  
        double Hyp = Math.sqrt(X * X + Y * Y);  
        double Lat = Math.atan2(Z, Hyp);  
        QueryEntity ql = new QueryEntity();
        ql.setX(Double.toString(Lon * 180 / Math.PI));
        ql.setY(Double.toString(Lat * 180 / Math.PI));
        ql.setName("center");
        
        return ql;
    }

 

計算算的點之間的距離在400km以內的可以使用簡化的 代碼

private QueryEntity getCentPoint(List<QueryEntity> pointlist){
        int total = pointlist.size();  
       double lat, lon, x, y, z;   
        for (QueryEntity g : pointlist)  
        {  
            lat += (Double.parseDouble(g.getY())) * Math.PI / 180;  //緯度
            lon += (Double.parseDouble(g.getX())) * Math.PI / 180;  //經度
         
        }  
        lat /= total;  
        lon /=total; 
        QueryEntity ql = new QueryEntity();
        ql.setX(Double.toString(Lon * 180 / Math.PI));
        ql.setY(Double.toString(Lat * 180 / Math.PI));
        ql.setName("center");
        
        return ql;
    }