Here is a module that I wrote for that purpose. It will have to be modified for your needs, but should give you a good starting point for further development. Someday I will get around to making it an independent module. HTH

package Zips;
use strict;
use Time::HiRes qw(gettimeofday);

sub get_coords {
    my ($s) = shift;
    my $dbh = $s->dbh;
    my ($zip) = @_;
    my $sth = $dbh->prepare(qq! SELECT lat,lng FROM zipcodes WHERE zip
+='$zip' !);
    $sth->execute();
    my ($lat,$lng) = $sth->fetchrow();
    $sth->finish();
    return ($lat,$lng);
}

sub radius_select {
    my ($s) = shift;
    my $dbh = $s->dbh;
    my ($zip,$m) = @_;
    my ($lat, $lng) = $s->get_coords($zip);
    if (($lat)&&($lng)) {
        print "<div align=center>Lat: $lat Long: $lng</div>\n";
        my $d = $m / 3958.75;
        my $div = 57.2958;
        my $sth = $dbh->prepare(qq!
                                   SELECT zip,cname,state, ( 3958.75 *
+ ACOS( COS($lat/$div
) * COS(lat/$div)
                                   + SIN($lat/$div) * SIN(lat/$div)
                                   * COS($lng/$div - lng/$div) ) ) as 
+dist  FROM zipcodes
                                   WHERE (ACOS( COS($lat/$div) * COS(l
+at/$div)
                                   + SIN($lat/$div) * SIN(lat/$div)
                                   * COS($lng/$div - lng/$div) )) < $d
                                   ORDER BY dist
                                !) || die "Can't select from zipcodes:
+ ", $dbh->errstr;
        #$s->write_log($sth->{Statement});
        my $b = gettimeofday;
        $sth->execute() || die "Can't execute select on zipcodes: ", $
+sth->errstr;
        $s->e->{'qtime'} = gettimeofday-$b;
        my $r_all = $sth->fetchall_arrayref();
        $sth->finish();
        return $r_all;
    } else {
        print "Invalid Zip Code.\n";
    }
}

sub get_limit_byzip {
    my ($s) = shift;
    my $dbh = $s->dbh;
    my ($zip,$m) = @_;

    my $d = 200 / 3958.75;
    my ($lat, $lng) = $s->get_coords($zip);
    if (($lat)&&($lng)) {
        print "<div align=center>Lat: $lat Long: $lng</div>\n";
        my $d = $m / 3958.75;
        my $div = 57.2958;
        my $sth = $dbh->prepare(qq!
                                   SELECT zip,cname,state, ( 3958.75 *
+ ACOS( COS($lat/$div
) * COS(lat/$div)
                                   + SIN($lat/$div) * SIN(lat/$div)
                                   * COS($lng/$div - lng/$div) ) ) as 
+dist  FROM zipcodes
                                   WHERE (ACOS( COS($lat/$div) * COS(l
+at/$div)
                                   + SIN($lat/$div) * SIN(lat/$div)
                                   * COS($lng/$div - lng/$div) )) < $d
                                    Group by dist limit $m
                                !) || die "Can't select from zipcodes:
+ ", $dbh->errstr;
        #$s->write_log($sth->{Statement});
        my $b = gettimeofday;
        $sth->execute() || die "Can't execute select on zipcodes: ", $
+sth->errstr;
        $s->e->{'qtime'} = gettimeofday-$b;
        my $r_all = $sth->fetchall_arrayref();
        $sth->finish();
        return $r_all;
    } else {
        print "Invalid Zip Code.\n";
    }
}

sub get_dist_byzip {
    my ($s)             = shift;
    my ($zip, $zip2)    = @_;
    my ($lat, $lng)     = $s->get_coords($zip);
    my ($lat2,$lng2)    = $s->get_coords($zip2);
    my $div             = 57.2958;
    my $dist = (3958.75 * acos( cos($lat/$div) * cos($lat2/$div)
                             + sin($lat/$div) * sin($lat2/$div)
                             * cos($lng/$div - $lng2/$div) ) );
    return $dist;
}

sub get_zips_bycity {
    my ($s) = shift;
    my ($city,$state,$dist) = @_;
    my $sth = $s->dbh->prepare(qq! SELECT zip FROM zipcodes WHERE cnam
+e='$city' and state=
'$state' !);
    $sth->execute();
    my $zip = $sth->fetchrow();
    $sth->finish();
    return $s->radius_select($zip,$dist);
}

sub acos { atan2( sqrt(1 - $_[0] * $_[0]), $_[0] ); }

1;

__END__

=pod

=head1 NAME

    Zips.pm

=head1 METHODS AVAILABLE

$s->get_zips($zip, $dist)

$s->get_coords($zip)    => ($lat,$lng);

$s->radius_select($zip,$m)  => $r_all;

$s->dist_select_byzip($zip, $zip2)  => $dist;

$s->acos()

=head1 AUTHOR

Stephen T. Walker <swalker@ssdw.com>

August 2000

=cut
[download]

---

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