<?php
/*******************************************************************************
* ZIP Code and Mileage Claculation Class
*******************************************************************************
* Author: Micah Carrick
* Email: email@micahcarrick.com
* Website: http://www.micahcarrick.com
*
* File: zipcode.class.php
* Version: 1.00
* Copyright: (c) 2005 - Micah Carrick
* You are free to use, distribute, and modify this software
* under the terms of the GNU General Public License. See the
* included license.txt file.
*
*******************************************************************************
* VERION HISTORY:
*
* v1.00 [04.12.2005] - Initial Version
*
*******************************************************************************
* DESCRIPTION:
*
* This is a class used to do various zipcode calculations such as distance
* and finding the zip codes within range of another zip code. It uses
* a mySQL database based on the text file found for free on the internet
* at http://www.cfdynamics.com/cfdynamics/zipbase/index.cfm. Visit that
* page for additional information on that data.
*
*******************************************************************************
*/
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 = "m"; // m = miles, k = 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 -1 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 (empty($details1)) {
$this->last_error = "No details found for zip code: $zip1";
return -1;
}
if (empty($details2)) {
$this->last_error = "No details found for zip code: $zip2";
return -1;
}
// 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 == 'k') return round($miles * 1.609344, $this->decimals);
else return round($miles, $this->decimals); // assumed $units = 'm'
}
function get_zip_details($zip) {
// This function pulls the details from the database for a
// given zip code.
$sql = "SELECT lattitude, longitude, city, state.state_prefix, state_name,
zip_class from zip_code, state
WHERE zip_code=$zip
AND zip_code.state_prefix=state.state_prefix";
$r = mysql_query($sql);
if (!$r) {
$this->last_error = mysql_error();
return;
} 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.
$sql = "SELECT lattitude, longitude from zip_code WHERE zip_code=$zip";
$r = mysql_query($sql);
if (!$r) {
$this->last_error = mysql_error();
return;
} else {
$row = mysql_fetch_array($r);
mysql_free_result($r);
return $row;
}
}
function calculate_mileageA($lat1, $lat2, $lon1, $lon2) {
// This function is not used right now. This is based on code found
// all over the internet such as 4guysfromrolla.com. It's not clear
// who the original author was.
$dist = sin(deg2rad($lat1)) * sin(deg2rad($lat2));
$dist = $dist+cos(deg2rad($lat1))*cos(deg2rad($lat2))*cos(deg2rad($lon1 - $lon2));
$dist = acos($dist);
$dist = rad2deg($dist);
return $dist * 60 * 1.1515;
}
function calculate_mileage($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) {
// 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 (empty($details)) return;
$return = array(); // declared here for scope
$sql = "SELECT zip_code, lattitude, longitude FROM zip_code
WHERE zip_code <> $zip";
$r = mysql_query($sql);
if (!$r) { // sql error
$this->last_error = mysql_error();
return;
} else {
while ($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 == 'k') $dist = $dist * 1.609344;
if ($dist <= $range) {
$return[str_pad($row[0], 5, "0", STR_PAD_LEFT)] = round($dist, $this->decimals);
}
}
mysql_free_result($r);
}
$this->last_time = $this->chronometer();
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;
}
}
}
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