function geo_douglaspeucker_simplify(&$data, $tolerance = 0.0001)
{
$geopoints = array();
$simplified = array();
foreach ($data as $dot) {
$geopoints[] = new GeoPoint($dot['latitude'], $dot['longitude'], $dot);
}
$reducer = new PolylineReducer($geopoints);
foreach ($reducer->SimplerLine($tolerance) as $dot) {
$simplified[] = $dot;
}
return $simplified;
}
function simplePolyline($points)
{
$reducer = new PolylineReducer($points);
$simple = $reducer->SimplerLine(0.001);
$p = new PolylineEncoder();
$pl = $p->dpEncode($simple);
return $pl[2];
}