UK Postcode Proximity....

The_Chancer

Anyone know of a way to do a full UK Postcode Proximity search ? (ie return all postcodes within eg. 5 miles of a certain postcode)

Been looking but can't find owt.... 🙁

Shrike

I had a quick look at this one: http://www.cgi-interactive-uk.com/uk_postcodes.html. It seems to work and the company will provide you with updated grid data each quarter. It costs £300 though, but the updates are free. It's used to find the distance between postcodes but it seems logical that the data could be used to do what you want.

The_Chancer

Managed to find the calculation for this....

3963.0 * arccos[sin(lat1/57.2958) * sin(lat2/57.2958) + cos(lat1/57.2958) * cos(lat2/57.2958) *  cos(lon2/57.2958 -lon1/57.2958)]

Now all I need is the long & lat for each postcode district.... should be able to get those for free from somewhere... (even if a little outdated - means I can show as a display - then get the client to buy the full lot !!!) 🙂

Drakla

You can get a free database, though it's a bit limited, from http://www.jibble.org/ukpostcodes/ but it only has a small resolution.

Tip is if you put them in a database don't do the maths first to turn your search area in a circle, grab back stuff first with WHERE Xcoord BETWEEN $xMin AND $xMax to eliminate 99% of the data so you've got a box, then do your maths on the rest of it.

piersk

Shrike wrote:
I had a quick look at this one: http://www.cgi-interactive-uk.com/uk_postcodes.html. It seems to work and the company will provide you with updated grid data each quarter. It costs £300 though, but the updates are free. It's used to find the distance between postcodes but it seems logical that the data could be used to do what you want.

It seems that you can use it for free, but it displays a banner. I figure since MySQL make it clear they use GeoIP, I figure there may be some companies that don't mind having displaying a banner

The_Chancer

with the "free" limited (2800 ish records) According to the list from GVolt (I think) I am only missing about 200... not many..

<?php
include("db.php");
?>
<html>
<head>
<title>Show Close Postcode Areas</title>
</head>
<body>
<form name="postcode" method="post" action="<?php echo $_SERVER['PHP_SELF'];?>">
Input Postcode (M33 etc only) <input type="text" name="pcode" value="<?php echo $_POST['pcode'];?>"><br />
Input distance <input type="text" name="dist" value="<?php echo $_POST['dist'];?>"><br />
<input type="submit" name="submit" value="submit">
</form>
</body>
</html>
<?
if (isset($_POST['submit']))
{
	$pcode = $_POST['pcode'];
	$dist = $_POST['dist'];
	$query=do_query("SELECT lat,lon FROM postcodes WHERE postcode='".$pcode."'");
	list($lat,$long)=mysql_fetch_row($query);

$query=do_query("SELECT postcode,lat,lon FROM postcodes WHERE postcode!='".$pcode."'");
while(list($pcode2,$lat2,$long2)=mysql_fetch_row($query))
{
	if (3963.0*acos(sin($lat/57.2958)*sin($lat2/57.2958)+cos($lat/57.2958)*cos($lat2/57.2958)*cos(($long2/57.2958)-($long/57.2958)))<=$dist)
	{
		echo $pcode2." is close<br />";
	}
}
}
?>