$re = '/^(-?[1-8]?\d(?:\.\d{1,18})?|90(?:\.0{1,18})?),\s*?(-?(?:1[0-7]|[1-9])?\d(?:\.\d{1,18})?|180(?:\.0{1,18})?)$/mi';
$str = '47.338388, 0.990228
-47.338388, -0.990228
47.338388,0.990228
-47.338388,-0.990228';
preg_match_all($re, $str, $matches, PREG_SET_ORDER, 0);
// Print the entire match result
var_dump($matches);
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for PHP, please visit: http://php.net/manual/en/ref.pcre.php