Polyline Encoder is a simple PHP class that will help you work with polyline encoding / decoding. For more details about the polyline encoder algorithm, please refer to : https://developers.google.com/maps/documentation/utilities/polylinealgorithm
This project is under MIT and GPLv2 Licenses.
Just insert the following line at the top of your PHP file :
#require_once 'PolylineEncoder.php';
To encode a polyline just follow those steps :
$polylineEncoder = new PolylineEncoder();
$polylineEncoder->addPoint(30.5,-120.2);
$polylineEncoder->addPoint(40.7,-120.95);
$polylineEncoder->addPoint(43.252,-126.453);
$encodedString = $polylineEncoder->encodedString();
$decodedPoints = PolylineEncoder::decodeString("_p~iF~ps|U_ulLnnqC_mqNvxq`@");
Please note that the encoding levels are currently not supported.