NYCPHP Meetup

[Mark Armendariz]

here's a function i've ben using for a couple years now.  I can honestly say
I have no idea whether or not i wrote it as i'd done a LOT of variations of
it at the time.  From what I know it's worked well for around 2 years now
(for my client).  I've only tested with US values, but i imagine it should
work for other values as well.
 
Good luck!!

function getDistance($fromLatitude, $fromLongitude, $toLatitude,
$toLongitude) {
 
 /* assume your points, in decimal, are in $fromLongitude,$fromLatitude and
$toLongitude,$toLatitude 
 * this can also be useful with the US ZIPcodes at 
 *  <http://ftp.census.gov/geo/www/gazetteer/places.html>
http://ftp.census.gov/geo/www/gazetteer/places.html 
 */ 
 
 $Pi   = 3.1415926535897932384626;
 $Radius  = doubleval($Pi/180.0); 
 
 $fromLongitude  = doubleval($fromLongitude) * $Radius; $fromLatitude =
doubleval($fromLatitude) * $Radius; 
 $toLongitude   = doubleval($toLongitude) * $Radius; $toLatitude =
doubleval($toLatitude) * $Radius; 
 
 $theta = $toLongitude - $fromLongitude; 
 $Distance = acos(sin($fromLatitude) * sin($toLatitude) + cos($fromLatitude)
* cos($toLatitude) * cos($theta)); 
 if ($Distance < 0) {
  $Distance += $Pi;
 } 
 
 $Distance  = $Distance * 6371.2; 
 $Miles   = doubleval($Distance * 0.621);
 $Distance  = sprintf("%.2f", $Distance); 
 $Miles   = sprintf("%.4f", $Miles);
 
 return $Miles;
}
 

  _____  

From: talk-bounces at lists.nyphp.org [mailto:talk-bounces at lists.nyphp.org] On
Behalf Of Daniel Kushner
Sent: Thursday, November 20, 2003 10:54 PM
To: NYPHP Talk
Subject: RE: [nycphp-talk] Hello / Geo coords


Spot,
 
Here's some code that I have from a long time ago that calculates the
distance between airports based on longitude and latitude. You can do the
same with Zip codes once you convert a zip code to long/lat.
 
Best,
Daniel Kushner
 
$db = new My_DB("SELECT * 
      FROM airports AS a 
         WHERE id IN ('$origin', '$destination')");
 
 $db->next_record();
 $a = deg2rad($db->f('latitude'));
 $b = deg2rad($db->f('longitude'));
 $origin_id = $db->f('id');
 $origin_name = $db->f('name');
 
 $db->next_record();
 $c = deg2rad($db->f('latitude'));
 $d = deg2rad($db->f('longitude'));
 $destination_id = $db->f('id');
 $destination_name = $db->f('name');
 
 
 $r=3963.1; //radius of the earth in miles
 
 //calculate the distance between the two points
 $distance = acos(
      (cos($a) * cos($b) * cos($c) * cos($d)) + 
      (cos($a) * sin($b) * cos($c) * sin($d)) + 
      (sin($a) * sin($c))
     ) * $r;
     
 if($origin == $destination) {
  echo "Distance = 0<br>"; 
 } else {
  echo "Origin: ($origin_id) $origin_name<br>";
  echo "Destination: ($destination_id) $destination_name<br>";
  echo "Distance in miles: ", round($distance,4), "<br>";
  echo "Distance in kilometers: ", round(($distance*1.609),4), "<br>";
 }

-----Original Message-----
From: talk-bounces at lists.nyphp.org [mailto:talk-bounces at lists.nyphp.org]On
Behalf Of Spot
Sent: Thursday, November 20, 2003 2:56 PM
To: talk at lists.nyphp.org
Subject: [nycphp-talk] Hello / Geo coords


Hey everyone,
 
Just thought I would introduce myself as new member to the list and pose a
question at the same time.

My name is Spot(yes, legally). I am with deviantART.com. We are the largest
art community in the world with a little under 500,000 artists, almost 3
million pieces of art and close to 80 million hits a month. We move about
55mbit/s average. Running on 37 boxes (last I checked) and two 9 terabyte
fibre enclosures. All on Apache/PHP/Mysql. Except for Zues talking to the
fibre enclosures for raw data (images). All of our code is from the ground
up. No external libraries.

Currently we are employing somewhat of a locational system where we allow
artists to provide their Geo coords (after getting them from Maporama.com)
and then, currently using GeoURL.org, we pull in RSS feeds and allow them to
see lists of artists close to them.

We are interested in bringing as much of this "in-house" as possible.
Especially the GeoURL functionality. Does anyone have any information on
methods for creating "crow flies" distances between artists based on geo
coords? I would be interested in using a third party library if there is
one.
 
 
Thanks!

Spot
Director of Prints
deviantART Inc.
www.deviantart.com

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