Google maps coordinate names change with every release, so this code will help to abstract those names away, allowing the processing of the coordinates regardless of their name.

AbstractingGoogleMapsVars.php

<?php
// Abstract the google named variables to that if they change we can still read the values
$coords = [];
foreach ($bounds as $key => $value) {
	$coords[] = $value;
}

$first = get_object_vars($coords[0]);
$second = get_object_vars($coords[1]);

$corners['brLat'] = number_format($first[key($first)], 2);
next($second);
$corners['brLng'] = number_format($second[key($second)], 2);

prev($second);
next($first);
$corners['tlLat'] = number_format($first[key($first)], 2);
$corners['tlLng'] = number_format($second[key($second)], 2);