How to use geofencing in php?

This is the grogram to find latitude and longitude .

$filter_address =  "{$address_1'},{$'city'},{$'state'},{$'country'},{$'postcode'}";

$prepAddress = str_replace(' ', '+', $filter_address);

$output = json_decode(file_get_contents("http://maps.google.com/maps/api/geocode/json?address={$prepAddress}&sensor=false"));

$v_lat = $output->results[0]->geometry->location->lat;

$v_long = $output->results[0]->geometry->location->lng;