Calculate the Distance Between Two Points in PHP

There are a lot of applications where it is useful to know the distance between two coordinates. Here, you'll find a PHP function that takes the latitude and longitude of two points and returns the distance between them in both miles and metric units.

You can also use this to find the distance between two addresses by taking advantage of the Google Geotargetting API.

Here's the function:

1.   function get_distance_between_points($latitude1, $longitude1, $latitude2, $longitude2) {
2.   	$theta = $longitude1 - $longitude2;
3.   	$miles = (sin(deg2rad($latitude1)) * sin(deg2rad($latitude2))) + (cos(deg2rad($latitude1)) * cos(deg2rad($latitude2)) * cos(deg2rad($theta)));
4.   	$miles = acos($miles);
5.   	$miles = rad2deg($miles);
6.   	$miles = $miles * 60 * 1.1515;
7.   	$feet = $miles * 5280;
8.   	$yards = $feet / 3;
9.   	$kilometers = $miles * 1.609344;
10.  	$meters = $kilometers * 1000;
11.  	return compact('miles','feet','yards','kilometers','meters'); 
12.  }

And here's an example of the function in action, using two coordinates in New York City:

1.   $point1 = array('lat' => 40.770623, 'long' => -73.964367);
2.   $point2 = array('lat' => 40.758224, 'long' => -73.917404);
3.   $distance = getDistanceBetweenPointsNew($point1['lat'], $point1['long'], $point2['lat'], $point2['long']);
4.   foreach ($distance as $unit => $value) {
5.   	echo $unit.': '.number_format($value,4).'<br />';
6.   }

The example returns the following:

miles: 2.6025
feet: 13,741.4350
yards: 4,580.4783
kilometers: 4.1884
meters: 4,188.3894


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This post was published on April 26th, 2011 by Robert James Reese in the following categories: Maps and PHP. Before using any of the code or other content in this post, you must read and agree to our terms of use.