NAME

       Geo::Hash::XS - Geo::Hash in XS

SYNOPSIS

           my $gh = Geo::Hash::XS->new();
           my $hash = $gh->encode( $lat, $lon );  # default precision = 32
           my $hash = $gh->encode( $lat, $lon, $precision );
           my ($lat, $lon) = $gh->decode( $hash );

DESCRIPTION

       Geo::Hash::XS encodes and decodes geohash strings, fast.

       Currently this module is alpha quality (especially the "adjacent()" and "negihbors()"
       methods, which I just kind of copied the logic from elsewhere). Please submit tests and
       patches!

METHODS

   $gh = Geo::Hash::XS->new()
   $hash = $gh->encode($lat, $lon[, $precision])
       Encodes the given $lat and $lon to a geohash. If $precision is not given, automatically
       adjusts the precision according the the given $lat and $lon values.

       If you do not want Geo::Hash::XS to spend time calculating this, explicitly specify
       $precision.

   ($lat, $lon) = $gh->decode( $hash )
       Decodes $hash to $lat and $lon

   ($lat_range, $lon_range) = $gh->decode_to_interval( $hash )
       Like "decode()" but "decode_to_interval()" decodes $hash to $lat_range and $lon_range.
       Each range is a reference to two element arrays which contains the upper and lower bounds.

   $adjacent_hash = $gh->adjacent($hash, $where)
       Returns the adjacent geohash. $where denotes the direction, so if you want the block to
       the right of $hash, you say:

           use Geo::Hash::XS qw(ADJ_RIGHT);

           my $gh = Geo::Hash::XS->new();
           my $adjacent = $gh->adjacent( $hash, ADJ_RIGHT );

   @list_of_geohashes = $gh->neighbors($hash, $around, $offset)
       Returns the list of neighbors (the blocks surrounding $hash)

   $precision = $gh->precision($lat, $lon)
       Returns the apparent required precision to describe the given latitude and longitude.

CONSTANTS

   ADJ_LEFT, ADJ_RIGHT, ADJ_TOP, ADJ_BOTTOM
       Used to specify the direction in "adjacent()"

PERFORMANCE

       Here's the output from running benchmark/encode.pl:

           Geo::Hash: 0.02
           Geo::Hash::XS: 0.00014

           precision = auto...
                    Rate  perl    xs
           perl  18332/s    --  -98%
           xs   964744/s 5163%    --

           precision = 5...
                     Rate  perl    xs
           perl   16500/s    --  -98%
           xs   1011557/s 6030%    --

           precision = 10...
                    Rate   perl     xs
           perl   8650/s     --   -99%
           xs   980236/s 11232%     --

           precision = 20...
                    Rate   perl     xs
           perl   4736/s     --   -99%
           xs   858875/s 18035%     --

           precision = 30...
                    Rate   perl     xs
           perl   3050/s     --  -100%
           xs   712136/s 23252%     --

       Obviously, the benefit of doing this calculation in XS becomes larger with higher
       precision, but generaly you don't need precision > 10.

LICENSE

       This program is free software; you can redistribute it and/or modify it under the same
       terms as Perl itself.

       See http://www.perl.com/perl/misc/Artistic.html

AUTHOR

       Copyright (c) 2010 Daisuke Maki <daisuke@endeworks.jp>