怎么存储google地图经度纬度比较好

$coord = array (
    0=>array (
        "x" => "102.00001",
        "y" => "20.12321"
    ),
    1=>array (
        "x" => "300.22",
        "y" => "111.22"
    ),
    2=>array (
        "x" => "202.1121",
        "y" => "30.2122"
    )
);
$str = json_encode($coord);
echo $str;
//[{"x":"102.00001","y":"20.12321"},{"x":"300.22","y":"111.22"},{"x":"202.1121","y":"30.2122"}]