NAME

Geo::Hash - Encode / decode geohash.org locations.

VERSION

This document describes Geo::Hash version 0.02

SYNOPSIS

    use Geo::Hash;

    my $gh = Geo::Hash->new;
    my $hash = $gh->encode( $lat, $lon );
    my ( $lat, $lon ) = $gh->decode( $hash );

DESCRIPTION

Geohash is a latitude/longitude geocode system invented by Gustavo Niemeyer when writing the web service at geohash.org, and put into the public domain.

This module encodes and decodes geohash locations.

See http://en.wikipedia.org/wiki/Geohash and http://geohash.org for more information.

INTERFACE

new

Create a new Geo::Hash object.

    my $gh = Geo::Hash->new;

precision

Infer a suitable precision (number of character in hash) for a given lat, lon pair.

    my $prec = $gh->precision( $lat, $lon );

encode

Encode a lat, long pair into a geohash.

    my $hash = $gh->encode( $lat, $lon );

You may optionally supply the length of the desired geohash:

    # Very precise
    my $hash = $gh->encode( $lat, $lon, 10 );

If the precision argument is omitted precision will be used to provide a default.

decode_to_interval

Like decode but instead of returning a pair of coordinates returns the interval for each coordinate. This gives some indication of how precisely the original hash specified the location.

The return value is a pair of array refs. Each referred to array contains the upper and lower bounds for each coordinate.

    my ( $lat_range, $lon_range ) = $gh->decode_to_interval( $hash );
    # $lat_range and $lon_range are references to two element arrays

decode

Decode a geohash into a lat, long pair.

    my ( $lat, $lon ) = $gh->decode( $hash );

CONFIGURATION AND ENVIRONMENT

Geo::Hash requires no configuration files or environment variables.

DEPENDENCIES

None.

INCOMPATIBILITIES

None reported.

BUGS AND LIMITATIONS

No bugs have been reported.

Please report any bugs or feature requests to bug-geo-hash@rt.cpan.org, or through the web interface at http://rt.cpan.org.

AUTHOR

Andy Armstrong <andy@hexten.net>

http://geohash.org/gcwrdtsvrfgr

LICENCE AND COPYRIGHT

Copyright (c) 2008, Andy Armstrong <andy@hexten.net>.

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