The ability to search for users near a particular zip code would save a lot of browsing time. Example: find all users who live within 5, 10, 25, 50, 100+ miles of zip code 12345.

Maybe the Google Maps CB plugin could be a start for that, though I don't think the API currently makes it wasy to pick up distances between addresses, or anything for that matter.

Might be able to use a geocoder external from Google. Don't know much about how it'd work with a CB profile search, but I can imagine a plugin outputting something like...

"This user is 4,460 miles km/inches from you."

so long as you have fields for your coordinates stored somewhere and a way to geocode the difference between them.

Might be a good feature request for the Google Maps developer.

Another thing is that a ZIP code search using Google Maps doesn't really help a good 90% of the world.

Might be able to use a geocoder external from Google. Don't know much about how it'd work with a CB profile search, but I can imagine a plugin outputting something like...

"This user is 4,460 miles km/inches from you."

Such a plugin would be the solution if the mileage could be sorted, so that the user nearest you is at the top of the "Search User" results. This would happen automatically, requiring no input from the user. I suppose that there would also be a setting in the configuration for sorting preference, just in case there are other ways to sort user lists.

I found this:
www.zend.com/codex.php?id=1486&single=1

[code:1]
<?php
/*******************************************************************************
* ZIP Code and Mileage Claculation Class
*******************************************************************************
* Author: Micah Carrick
* Email: email@micahcarrick.com
* Website: 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 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 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;
}
}

}
[/code:1]

How hard would it be to make this work for community builder?