Weblog of Alif

Exploring the Web: An Apple a day

Getting Lat and Lon from Address in Google Maps Using PHP

December 29, 2010 -- alif

Recently, I am working on an application where I have to convert addresses to their corresponding Lat and Lon. So, I decided to write on how to get Latitude and Longitude in Google Maps using only PHP.

To use the technique explained below, you need to have a Google Maps Key.

I have posted another article, where you do not even need a Google Maps API Key to get the Lat and Lon. Read here

The idea is simple. Make a request to Google Maps server, and it will return an XML (or JSON). Then, parse the XML to get the Lat and Lon. I use DomDocument and DomXPath for processing it.

Below I have used the address: 100 City Centre Dr., Mississauga, Ontario.


$key  = "....."; // your Google Maps key

$address = urlencode('100 City Centre Dr., Mississauga, ON');

$url = 'http://maps.google.com/maps/geo?q='.$address.'&output=xml&oe=utf8&key='.$key;
$dom = new DomDocument();
$dom->load($url);

At this point, the XML is loaded into the $dom. Now, its about processing it and getting the Lat and Lon

The XML looks like below (it has been shortened):


  100 City Centre Dr., Mississauga, ON
  200geocode
  
    
100 City Centre Dr, Mississauga, ON L5B 2G6, Canada
....... -79.6422503,43.5931076,0
..........

As can be seen, it has lots of data. However, we are only interested in the coordinates and the Status code. On coordinates, the first floating number is Lon and the second is Lat. We need to extract those two separately.

So, I load the XML in a DomXPath, and run an XPath query to extract the Lat and Lon from it


$xpath = new DomXPath($dom);
$xpath->registerNamespace('ge', 'http://earth.google.com/kml/2.0');
	
$statusCode = $xpath->query('//ge:Status/ge:code');

// Check if statusCode = 200	
if ($statusCode->item(0)->nodeValue == '200') {
	
	$pointStr = $xpath->query('//ge:coordinates');
	$point = explode(",", $pointStr->item(0)->nodeValue);
	
	$lat = $point[1];
	$lon = $point[0];

	echo '
';
	echo 'Lat: '.$lat.', Lon: '.$lon;
	echo '
'; }

Thats about it :). I have attached a sample file. Please insert your key there and rename .txt to .php and you should be good to go!.

AttachmentSize
latlon.php_.txt896 bytes

Comments

Submitted by Ashif (not verified) on

hey thanks for this great work. I am a student and looking for some help. How do you make this work with the google maps api version 3.0? Please advice.

Thanks,

Ashif

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