Find the nearest Taxi to one point

taxi.php

<?php
/* 
* Calculate the distance between 2 coordinates
* By James Roffey - https://jroffey.me
*/
if(isset($_GET["lat"]) && isset($_GET["lon"])){
	$pickup = array($_GET["lat"], $_GET["lon"]);
	
	$taxis = array(
		0 => array ('id' => '1','driverid' => '1','lat' => '51.873675','lon' => '0.544403','online' => '1','number_plate' => 'FE07 RAB'),
		1 => array ('id' => '2','driverid' => '2','lat' => '51.868801','lon' => '0.559987','online' => '1','number_plate' => 'FE07 RDY'),
		2 => array ('id' => '3','driverid' => '3','lat' => '51.873233','lon' => '0.561296','online' => '1','number_plate' => 'FH05 ROS')
	);


	$nearest = null;
	$thetaxi = 0;
	foreach($taxis as $taxi){
		$dist = distance(array($taxi["lat"], $taxi["lon"]), $pickup);
		
		if($dist < $nearest || $nearest == null){
			$nearest = $dist;
			$thetaxi = $taxi;
		}
		
	}

	
	echo "
	Number Plate: {$thetaxi["number_plate"]} Taxi ID: {$thetaxi["id"]}<br />
	<a href='https://www.google.com/maps/search/?api=1&query={$thetaxi["lat"]},{$thetaxi["lon"]}'>Taxi is here</a><br />";

	
}

?>