echo '<h3>A sample getting all the zip codes withing a range: 2 miles from 97214</h3>';


$zips = $z->get_zips_in_range('97214', 2, _ZIPS_SORT_BY_DISTANCE_ASC, true); 


if ($zips === false) echo 'Error: '.$z->last_error;
else {
   
   foreach ($zips as $key => $value) {
      echo "Zip code <b>$key</b> is <b>$value</b> miles away from <b>97214</b>.<br />";


   }

// constants for setting the $units data member
define('_UNIT_MILES', 'm');
define('_UNIT_KILOMETERS', 'k');

// constants for passing $sort to get_zips_in_range()
define('_ZIPS_SORT_BY_DISTANCE_ASC', 1);
define('_ZIPS_SORT_BY_DISTANCE_DESC', 2);
define('_ZIPS_SORT_BY_ZIP_ASC', 3);
define('_ZIPS_SORT_BY_ZIP_DESC', 4);

// constant for miles to kilometers conversion
define('_M2KM_FACTOR', 1.609344);

class zipcode_class {

   var $last_error = "";            // last error message set by this class
   var $last_time = 0;              // last function execution time (debug info)
   var $units = _UNIT_MILES;        // miles or kilometers
   var $decimals = 2;               // decimal places for returned distance

   function get_distance($zip1, $zip2) {

      // returns the distance between to zip codes.  If there is an error, the 
      // function will return false and set the $last_error variable.
      
      $this->chronometer();         // start the clock
      
      if ($zip1 == $zip2) return 0; // same zip code means 0 miles between. :)
   
   
      // get details from database about each zip and exit if there is an error
      
      $details1 = $this->get_zip_point($zip1);
      $details2 = $this->get_zip_point($zip2);
      if ($details1 == false) {
         $this->last_error = "No details found for zip code: $zip1";
         return false;
      }
      if ($details2 == false) {
         $this->last_error = "No details found for zip code: $zip2";
         return false;
      }     


      // calculate the distance between the two points based on the lattitude
      // and longitude pulled out of the database.
      
      $miles = $this->calculate_mileage($details1[0], $details2[0], $details1[1], $details2[1]);
      
      $this->last_time = $this->chronometer();
 
      if ($this->units == _UNIT_KILOMETERS) return round($miles * _M2KM_FACTOR, $this->decimals);
      else return round($miles, $this->decimals);       // must be miles
      
   }   

   function get_zip_details($zip) {
      
      // This function pulls the details from the database for a 
      // given zip code.
 
      $sql = "SELECT lat AS lattitude, lon AS longitude, city, county, state_prefix, 
              state_name, area_code, time_zone
              FROM zip_code 
              WHERE zip_code='$zip'";
              
      $r = mysql_query($sql);
      if (!$r) {
         $this->last_error = mysql_error();
         return false;
      } else {
         $row = mysql_fetch_array($r, MYSQL_ASSOC);
         mysql_free_result($r);
         return $row;       
      }
   }

   function get_zip_point($zip) {
   
      // This function pulls just the lattitude and longitude from the
      // database for a given zip code.
      
      $sql = "SELECT lat, lon from zip_code WHERE zip_code='$zip'";
      $r = mysql_query($sql);
      if (!$r) {
         $this->last_error = mysql_error();
         return false;
      } else {
         $row = mysql_fetch_array($r);
         mysql_free_result($r);
         return $row;       
      }      
   }

   function calculate_mileage($lat1, $lat2, $lon1, $lon2) {
 
      // used internally, this function actually performs that calculation to
      // determine the mileage between 2 points defined by lattitude and
      // longitude coordinates.  This calculation is based on the code found
      // at http://www.cryptnet.net/fsp/zipdy/
       
      // Convert lattitude/longitude (degrees) to radians for calculations
      $lat1 = deg2rad($lat1);
      $lon1 = deg2rad($lon1);
      $lat2 = deg2rad($lat2);
      $lon2 = deg2rad($lon2);
      
      // Find the deltas
      $delta_lat = $lat2 - $lat1;
      $delta_lon = $lon2 - $lon1;
	
      // Find the Great Circle distance 
      $temp = pow(sin($delta_lat/2.0),2) + cos($lat1) * cos($lat2) * pow(sin($delta_lon/2.0),2);
      $distance = 3956 * 2 * atan2(sqrt($temp),sqrt(1-$temp));

      return $distance;
   }
   
   function get_zips_in_range($zip, $range, $sort=1, $include_base) {
       
      // returns an array of the zip codes within $range of $zip. Returns
      // an array with keys as zip codes and values as the distance from 
      // the zipcode defined in $zip.
      
      $this->chronometer();                     // start the clock
      
      $details = $this->get_zip_point($zip);  // base zip details
      if ($details == false) return false;
      
      // This portion of the routine  calculates the minimum and maximum lat and
      // long within a given range.  This portion of the code was written
      // by Jeff Bearer (http://www.jeffbearer.com). This significanly decreases
      // the time it takes to execute a query.  My demo took 3.2 seconds in 
      // v1.0.0 and now executes in 0.4 seconds!  Greate job Jeff!
      
      // Find Max - Min Lat / Long for Radius and zero point and query
      // only zips in that range.
      $lat_range = $range/69.172;
      $lon_range = abs($range/(cos($details[0]) * 69.172));
      $min_lat = number_format($details[0] - $lat_range, "4", ".", "");
      $max_lat = number_format($details[0] + $lat_range, "4", ".", "");
      $min_lon = number_format($details[1] - $lon_range, "4", ".", "");
      $max_lon = number_format($details[1] + $lon_range, "4", ".", "");

      $return = array();    // declared here for scope

      $sql = "SELECT zip_code, lat, lon FROM zip_code ";
      if (!$include_base) $sql .= "WHERE zip_code <> '$zip' AND ";
      else $sql .= "WHERE "; 
      $sql .= "lat BETWEEN '$min_lat' AND '$max_lat' 
               AND lon BETWEEN '$min_lon' AND '$max_lon'";
             
      $r = mysql_query($sql);
      
      if (!$r) {    // sql error

         $this->last_error = mysql_error();
         return false;
         
      } else {
          
         while ($row = mysql_fetch_row($r)) {
   
            // loop through all 40 some thousand zip codes and determine whether
            // or not it's within the specified range.
            
            $dist = $this->calculate_mileage($details[0],$row[1],$details[1],$row[2]);
            if ($this->units == _UNIT_KILOMETERS) $dist = $dist * _M2KM_FACTOR;
            if ($dist <= $range) {
               $return[str_pad($row[0], 5, "0", STR_PAD_LEFT)] = round($dist, $this->decimals);
            }
         }
         mysql_free_result($r);
      }
      
      // sort array
      switch($sort)
      {
         case _ZIPS_SORT_BY_DISTANCE_ASC:
            asort($return);
            break;
            
         case _ZIPS_SORT_BY_DISTANCE_DESC:
            arsort($return);
            break;
            
         case _ZIPS_SORT_BY_ZIP_ASC:
            ksort($return);
            break;
            
         case _ZIPS_SORT_BY_ZIP_DESC:
            krsort($return);
            break; 
      }
      
      $this->last_time = $this->chronometer();
      
      if (empty($return)) return false;
      return $return;
   }

   function chronometer()  {
 
   // chronometer function taken from the php manual.  This is used primarily
   // for debugging and anlyzing the functions while developing this class.  
  
   $now = microtime(TRUE);  // float, in _seconds_
   $now = $now + time();
   $malt = 1;
   $round = 7;
  
   if ($this->last_time > 0) {
       /* Stop the chronometer : return the amount of time since it was started,
       in ms with a precision of 3 decimal places, and reset the start time.
       We could factor the multiplication by 1000 (which converts seconds
       into milliseconds) to save memory, but considering that floats can
       reach e+308 but only carry 14 decimals, this is certainly more precise */
      
       $retElapsed = round($now * $malt - $this->last_time * $malt, $round);
      
       $this->last_time = $now;
      
       return $retElapsed;
   } else {
       // Start the chronometer : save the starting time
    
       $this->last_time = $now;
      
       return 0;
   }
}

}

<!DOCTYPE HTML PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
   <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
   <title>Zip Code Range and Distance Calculation Demo</title>
   <style type="text/css" lang="en">
   BODY, P { font-family: sans-serif; font-size: 9pt; }
   H3 { font-family: sans-serif; font-size: 14pt; }
   </style>
</head>
<body>

<?php

/*  
   DEMO for using the zipcode PHP class. By: Micah Carrick 
   Questions?  Comments?  Suggestions?  email@micahcarrick.com
*/

require_once('zipcode.class.php');      // zip code class


// Open up a connection to the database.  The sql required to create the MySQL
// tables and populate them with the data is in the /sql subfolder.  You can
// upload those sql files using phpMyAdmin or a MySQL prompt.  You will have to
// modify the below information to your database information.  
mysql_connect('localhost','php_user','php_user') or die(mysql_error()); 
mysql_select_db('test') or die(mysql_error()); 



// Below is an example of how to calculate the distance between two zip codes.

echo '<h3>A sample calculating the distance between 2 zip codes: 93001 and 60618</h3>';

$z = new zipcode_class;
$miles = $z->get_distance(97214, 98501);

if ($miles === false) echo 'Error: '.$z->last_error;
else echo "Zip code <b>97214</b> is <b>$miles</b> miles away from <b>98501</b>.<br />";



// Below is an example of how to return an array with all the zip codes withing
// a range of a given zip code along with how far away they are.  The array's
// keys are assigned to the zip code and their value is the distance from the
// given zip code.  

echo '<h3>A sample getting all the zip codes withing a range: 2 miles from 97214</h3>';

$zips = $z->get_zips_in_range('97214', 2, _ZIPS_SORT_BY_DISTANCE_ASC, true); 


if ($zips === false) echo 'Error: '.$z->last_error;
else {
   
   foreach ($zips as $key => $value) {
      echo "Zip code <b>$key</b> is <b>$value</b> miles away from <b>97214</b>.<br />";
   }
   
   // One thing you may want to do with this is create SQL from it. For example, 
   // iterate through the array to create SQL that is something like:
   // WHERE zip_code IN ('93001 93002 93004')
   // and then use that condition in your query to find all pizza joints or 
   // whatever you're using it for. Make sense? Hope so.
   
   echo "<br /><i>get_zips_in_range() executed in <b>".$z->last_time."</b> seconds.</i><br />";
}

// And one more example of using the class to simply get the information about
// a zip code.  You can then do whatever you want with it.  The array returned
// from the function has the database field names as the keys.  I just do a 
// couple string converstions to make them more readable.

echo '<h3>A sample getting details about a zip code: 97214</h3>';

$details = $z->get_zip_details('97214');

if ($details === false) echo 'Error: '.$z->last_error;
else {
   foreach ($details as $key => $value) {
      $key = str_replace('_',' ',$key);
      $key = ucwords($key);
      echo "$key: $value<br />";
   } 
}
?>