PHP: GMAP distance Class

gmap.php

<?php
/**
 * @package Distance
 * @license GPL
 * 
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA 
 * 
 * @uses Distance calculating Class, using Google Maps API for getting Latitude and Longitude. Distance calculation based on the Haversine Formula
 * @author	Csanad Novak <csanad@novak.net.nz> 
 * @copyright Csanad Novak <http://csanad.novak.net.nz>
 * @version 1.0
 * @since 10.2011
 */

class Distance 
{

	private $earthRadiusinKM = 6371.00; # in km
	private $earthRadiusinMiles = 3960.00; # in miles
	
	private $dLatitude = "";
	private $dLongitude = "";
	
	public $firstCoordinates = array();
	public $secondCoordinates = array();
	
	public $resultArray = array();
	

public function setEarthRadius($metric='km')
{
		if ($metric != 'km')
		{
			$this->earthRadius = $this->earthRadiusinMiles;	
		
		} else {
			
			$this->earthRadius = $this->earthRadiusinKM;	
		} 
}

/**
 *  @method Calculating distance between two address
 *  @access public
 *  @param 	$address1 is string passed to the Google Maps API Geocoding endpoint
 *  @param 	$address2 is string passed to the Google Maps API Geocoding endpoint
 *  @return string, contains the distance in km.
 */
public function distance_two_point ($address1, $address2)
{
	$this->firstCoordinates = $this->getAddressCoordinates($address1);
	$this->firstLatitude = $this->firstCoordinates[1];
	$this->firstLongitude = $this->firstCoordinates[0];
	
	$this->secondCoordinates = $this->getAddressCoordinates($address2);
	$this->secondLatitude = $this->secondCoordinates[1];
	$this->secondLongitude = $this->secondCoordinates[0];
	
	$this->resultDistance = $this->distance_haversine($this->firstLatitude, $this->firstLongitude, $this->secondLatitude, $this->secondLongitude);
	
	return $this->resultDistance;
}

/**
 *  @method Retriving geo coordinates for an address
 *  @access public
 *  @param 	$address is string passed to the Google Maps API Geocoding endpoint
 *  @return array. First element [0] is longitude, the second element [1] is the latitude
 */
public function getAddressCoordinates($address)
{
	 if (!is_string($address))
	 {
			die ("All Addresses must be passed as a string");
	 }
	  
			$apiURL = "http://maps.google.com/maps/geo?&output=xml&key=ABQIAAAAJUqzkGTwxHyfr_AFlet6FRSqiy-aFjcz-2DijvkBG8XEujeXPxSyYk3YLvgZJq0HyHrB2gCTJJRVAg&q=";
			$addressData = file_get_contents($apiURL.urlencode($address));
		
		$results = $this->xml2array($addressData);
		
		if (empty($results['Point']['coordinates']))
		{
			$result = "Error: Invalid address or missing coordinates";
			
		} else {
		  	
		  	$result = explode (",",$results['Point']['coordinates']);
		}
		
		return $result;
}

/**
 * 
 * @method Take a target address, check the distances with every address was defined in the $options array, then return result the closest - $sortorder = 'asc' - or the farest - $sortorder = 'desc'
 * @access public
 * @param string: $target, the first address
 * @param array: $options, multidimension array of addresses you want to get the distance (example: $options = array ('0' => array ('id' => 2, 'address' => '285-299 Havelock Street, Ashburton'))
 * @param string: $order, possibel values: 'asc' or 'desc'
 * @return array
 */
public function getAddressesDistances($target, $options, $sortorder)
{
	if (!is_string($target))
	{
			die ("All addresses must be passed as a string");
	}
	if (!is_array($options))
	{
			die ("All option addresses must be passed as an array");
	}
	
	$this->firstCoordinates = $this->getAddressCoordinates($target);
	$this->firstLatitude = $this->firstCoordinates[1];
	$this->firstLongitude = $this->firstCoordinates[0];
	
	foreach ($options as $key=>$value)
	{
		$this->secondCoordinates = $this->getAddressCoordinates($value['address']);
		$this->secondLatitude = $this->secondCoordinates[1];
		$this->secondLongitude = $this->secondCoordinates[0];
		
		$this->resultDistance = $this->distance_haversine($this->firstLatitude, $this->firstLongitude, $this->secondLatitude, $this->secondLongitude);
		
		$this->resultArray[$key]['id'] = $value['id'];
		$this->resultArray[$key]['distance'] = $this->resultDistance;
	}
	
	$this->resultArray = $this->sortmulti($this->resultArray, 'distance', $sortorder);
	
	return $this->resultArray[0];
}

/**
 * @method Calculating distance between two geo coordinates defined point, using the Haversine Formula
 * @link http://en.wikipedia.org/wiki/Haversine_formula
 * @access protected
 * @param $latitude1: float, the latitude coordinate for the first point
 * @param $longitude1: float, the longitude coordinate for the first point
 * @param $latitude2: float, the latitude coordinate for the second point
 * @param $longitude2: float, the longitude coordinate for the second point
 * @return float, the distance in km
 */
protected function distance_haversine($latitude1, $longitude1, $latitude2, $longitude2) 
{
	$this->dLatitude = $latitude2 - $latitude1 ;
	$this->dLongitude = $longitude2 - $longitude1 ;
  
	$alpha = $this->dLatitude/2;
	$beta = $this->dLongitude/2;
	  
	$a = sin(deg2rad($alpha)) * sin(deg2rad($alpha)) + cos(deg2rad($latitude1)) * cos(deg2rad($latitude2)) * sin(deg2rad($beta)) * sin(deg2rad($beta)) ;
	$c = asin(min(1, sqrt($a)));
	  
	$distance = 2*$this->earthRadius * $c;
	$distance = round($distance, 3);
	 
	return $distance;
}

/**
 * @method Sort multidemsional array based on an array index
 * @access protected
 * @param array: $array, must be multidimensional
 * @param string: $index, one of the $array indexes
 * @param string: $order, possibel values: 'asc' or 'desc'
 * @param binary: $natsort, natural sorting (check: http://php.net/manual/en/function.natsort.php)
 * @param binary: $case_sensitive
 * @return array, sorted
 */
protected function sortmulti ($array, $index, $order, $natsort=FALSE, $case_sensitive=FALSE) 
{
        
    	if(is_array($array) && count($array)>0) {
            foreach(array_keys($array) as $key)
            $temp[$key]=$array[$key][$index];
            if(!$natsort) {
                if ($order=='asc')
                    asort($temp);
                else   
                    arsort($temp);
            }
            else
            {
                if ($case_sensitive===true)
                    natsort($temp);
                else
                    natcasesort($temp);
            if($order!='asc')
                $temp=array_reverse($temp,TRUE);
            }
            foreach(array_keys($temp) as $key)
                if (is_numeric($key))
                    $sorted[]=$array[$key];
                else   
                    $sorted[$key]=$array[$key];
            return $sorted;
        }
    return $sorted;
}

/**
 *  The below functionality comes from PHPCLASS.ORG, Roger Veciana - Associative array to XML Class
 *  Transform an XML string to associative array "XML Parser Functions"
 */
protected function xml2array($xml)
{
		$this->depth=-1;
		$this->xml_parser = xml_parser_create();
		xml_set_object($this->xml_parser, $this);
		xml_parser_set_option ($this->xml_parser,XML_OPTION_CASE_FOLDING,0);//Don't put tags uppercase
		xml_set_element_handler($this->xml_parser, "startElement", "endElement");
		xml_set_character_data_handler($this->xml_parser,"characterData");
		xml_parse($this->xml_parser,$xml,true);
		xml_parser_free($this->xml_parser);
		return $this->arrays[3];
}

protected function startElement($parser, $name, $attrs)
{
	   $this->keys[]=$name; //We add a key
	   $this->node_flag=1;
	   $this->depth++;
}

protected function characterData($parser,$data)
{
	   $key=end($this->keys);
	   $this->arrays[$this->depth][$key]=$data;
	   $this->node_flag=0; //So that we don't add as an array, but as an element
}

protected function endElement($parser, $name)
{
	   $key=array_pop($this->keys);
	   //If $node_flag==1 we add as an array, if not, as an element
	   if($this->node_flag==1){
	     $this->arrays[$this->depth][$key]=$this->arrays[$this->depth+1];
	     unset($this->arrays[$this->depth+1]);
	   }
	   $this->node_flag=1;
	   $this->depth--;
} 
/**
 *  End of Roger Veciana - Associative array to XML Class
 */
	
}	
?>