Your fellow monks worked quite hard to help you out with this very same question over at this post: Zip code distance search. Please do not add a second post with a slightly different angle on the same question. We can't really give you the best possible help without seeing the whole history of answers and your response to them in one place.

Over there you provided an attempt at Perl code and that was a good thing. If you are still confused, add a reply to your original post explaining (a) what was helpful so far and (b) what you still aren't sure about. Doing so will keep the original post on the Recently Active Threads list for another day. If you think posting the original PHP code will help, add it to your replay to your original post over there

To further understand why this is a bad idea, please see this post by another user today who double posted a slightly different take on the same question.

Best, beth

Search CPAN for Math and you will find modules like Math::Trig that have all the functions like acos and deg2rad available in perl. The rest of the conversion seems trivial (like replacing "sub" for "function")

use strict;

sub distance {
    my ( $lat1, $lon1, $lat2, $lon2, $unit ) = @_;
    my $theta = $lon1 - $lon2;
    my $dist
        = sin( deg2rad($lat1) ) * sin( deg2rad($lat2) )
        + cos( deg2rad($lat1) ) * cos( deg2rad($lat2) ) *
        cos( deg2rad($theta) );
    $dist = acos($dist);
    $dist = rad2deg($dist);
    my $miles = $dist * 60 * 1.1515;
    $unit = uc $unit;
    if ( $unit eq "K" ) {
        return ( $miles * 1.609344 );
    } ## end if ( $unit eq "K" )
    elsif ( $unit eq "N" ) {
        return ( $miles * 0.8684 );
    } ## end elsif ( $unit eq "N" )
    else {
        return $miles;
    } ## end else [ if ( $unit eq "K" )
} ## end sub distance

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

sub deg2rad { $_[0] * 0.0174532925 }

sub rad2deg { $_[0] * 57.2957795 }
[download]

print distance(60.1843160, -128.5069940, 29.46786, -98.53506, "M"), " 
+miles\n";
print distance(32.9697, -96.80322, 29.46786, -98.53506, "K"), " kilome
+ters\n";
print distance(32.9697, -96.80322, 29.46786, -98.53506, "N"), " nautic
+al miles\n";
[download]

2535.33852270174 miles
422.738930838725 kilometers
228.109395841006 nautical miles
[download]

And if you go all the way and make use of the existing modules at CPAN:

use GIS::Distance;
my $gis = GIS::Distance->new();
$gis->formula('Cosine');
print $gis->distance( 60.1843160, -128.5069940 => 29.46786, -98.53506 
+)
    ->value('mile'), " miles\n";
print $gis->distance( 32.9697, -96.80322 => 29.46786, -98.53506 )
    ->value('kilometer'), " kilometers\n";
print $gis->distance( 32.9697, -96.80322 => 29.46786, -98.53506 )
    ->value('nautical_mile'), " nautical miles\n";
[download]

PHP is like "Perl light

I'd say it's more like Perl--. :P

And you didn't even know bears could type.