NAME
Geo::Google - Perform geographical queries using Google Maps
SYNOPSIS
use strict;
use Data::Dumper;
use Geo::Google;
#Allen's office
my $gonda_addr = '695 Charles E Young Dr S, Los Angeles, Los Angeles, California 90024, United States';
#Stan's Donuts
my $stans_addr = '10948 Weyburn Ave, Westwood, CA 90024';
#Roscoe's House of Chicken and Waffles
my $roscoes_addr = "5006 W Pico Blvd, Los Angeles, CA 90019";
#Instantiate a new Geo::Google object.
my $geo = Geo::Google->new();
#Create Geo::Google::Location objects. These contain
#latitude/longitude coordinates, along with a few other details
#about the locus.
my ( $gonda ) = $geo->location( address => $gonda_addr );
my ( $stans ) = $geo->location( address => $stans_addr );
my ( $roscoes ) = $geo->location( address => $roscoes_addr );
print $gonda->latitude, " / ", $gonda->longitude, "\n";
print $stans->latitude, " / ", $stans->longitude, "\n";
print $roscoes->latitude, " / ", $roscoes->longitude, "\n";
#Create a Geo::Google::Path object from $gonda to $roscoes
#by way of $stans.
my ( $donut_path ) = $geo->path($gonda, $stans, $roscoes);
#A path contains a series of Geo::Google::Segment objects with
#text labels representing turn-by-turn driving directions between
#two or more locations.
my @segments = $donut_path->segments();
#This is the human-readable directions for the first leg of the
#journey.
print $segments[0]->text(),"\n";
#Geo::Google::Segment objects contain a series of
#Geo::Google::Location objects -- one for each time the segment
#deviates from a straight line to the end of the segment.
my @points = $segments[1]->points;
print $points[0]->latitude, " / ", $points[0]->longitude, "\n";
#Now how about some coffee nearby?
my @coffee = $geo->near($stans,'coffee');
#Too many. How about some Coffee Bean & Tea Leaf?
@coffee = grep { $_->title =~ /Coffee.*?Bean/i } @coffee;
#Still too many. Let's find the closest with a little trig and
#a Schwartzian transform
my ( $coffee ) = map { $_->[1] }
sort { $a->[0] <=> $b->[0] }
map { [ sqrt(
($_->longitude - $stans->longitude)**2
+
($_->latitude - $stans->latitude)**2
), $_ ] } @coffee;
# Export a location as XML for part of a Google Earth KML file
my $strStansDonutsXML = $stans->toXML();
# Export a location as JSON data to use with Google Maps
my $strRoscoesJSON = $roscoes->toJSON();DESCRIPTION
Geo::Google provides access to the map data used by the popular Google Maps web application.
WHAT IS PROVIDED
- Conversion of a street address to a 2D Cartesian point (latitude/longitude)
- Conversion of a pair of points to a multi-segmented path of driving directions between the two points.
- Querying Google's "Local Search" given a point and one or more query terms.
WHAT IS NOT PROVIDED
- Documentation of the Google Maps map data XML format
- Documentation of the Google Maps web application API
- Functionality to create your own Google Maps web page.
AUTHOR
Allen Day <allenday@ucla.edu>, Michael Trowbridge <michael.a.trowbridge@gmail.com>
COPYRIGHT AND LICENSE
Copyright (c) 2004-2007 Allen Day. All rights reserved. This program is free software; you can redistribute it and/or modify it under the same terms as Perl itself.
BUGS / TODO
Report documentation and software bugs to the author, or better yet, send a patch. Known bugs/issues:
- Lack of documentation.
- JSON exporting is not exactly identical to the original Google JSON response. Some of the Google Maps-specific data is discarded during parsing, and the perl JSON module does not allow for bare keys while exporting to a JSON string. It should still be functionally interchangeable with a Google JSON reponse.
SEE ALSO
http://maps.google.com
http://www.google.com/apis/maps/
http://libgmail.sourceforge.net/googlemaps.htmlCONSTRUCTOR
new()
Usage : my $geo = Geo::Google->new();
Function : constructs and returns a new Geo::Google object
Returns : a Geo::Google object
Args : n/aOBJECT METHODS
error()
Usage : my $error = $geo->error();
Function : Fetch error messages produced by the Google Maps XML server.
Errors can be produced for a number of reasons, e.g. inability
of the server to resolve a street address to geographical
coordinates.
Returns : The most recent error string. Calling this method clears the
last error.
Args : n/alocation()
Usage : my $loc = $geo->location( address => $address );
Function : creates a new Geo::Google::Location object, given a
street address.
Returns : a Geo::Google::Location object, or undef on error
Args : an anonymous hash:
key required? value
------- --------- -----
address yes address to search for
id no unique identifier for the
location. useful if producing
XML.
icon no image to be used to represent
point in Google Maps web
application
infoStyle no unknown. css-related, perhaps?near()
Usage : my @near = $geo->near( $loc, $phrase );
Function : searches Google Local for records matching the
phrase provided, with the constraint that they are
physically nearby the Geo::Google::Location object
provided. search phrase is passed verbatim to Google.
Returns : a list of Geo::Google::Location objects
Args : 1. A Geo::Google::Location object
2. A search phrase.path()
Usage : my $path = $geo->path( $from, $OptionalWaypoints, $to );
Function : get driving directions between two points
Returns : a Geo::Google::Path object
Args : 1. a Geo::Google::Location object (from)
2. optional Geo::Google::Location waypoints
3. a Geo::Google::Location object (final destination)INTERNAL FUNCTIONS AND METHODS
_decode_word()
Usage : my $float = _decode_word($encoded_quintet_word);
Function : turn a quintet word into a float for the _decode() function
Returns : a float
Args : one data word made of ASCII characters carrying
a five-bit number per character from an encoded
Google polyline string_decode()
Usage : my @points = _decode($encoded_points);
Function : decode a polyline into its composite lat/lon pairs
Returns : an array of floats (lat1, long1, lat2, long2 ... )
Args : an encoded google polyline string_encode()
Usage : my $encoded_points = _encode(@points);
Function : encode lat/lon pairs into a polyline string
Returns : a string
Args : an array of coordinates [38.47823, -118.48571, 38.47845, -118.48582, ...]_encode_word()
Usage : my $encoded_quintet_word = _encode_word($signed_floating_point_coordinate);
Function : turn a signed float (either a full coordinate
or a delta) for the _encode() function
Returns : a string containing one encoded coordinate that
will be added to a polyline string
Args : one data word made of ASCII characters carrying
a five-bit number per character from an encoded
Google polyline string_html_unescape()
Usage : my $clean = _html_unescape($dirty);
Function : does HTML unescape of & > < " special characters
Returns : an unescaped HTML string
Args : an HTML string._obj2location()
Usage : my $loc = _obj2location($obj);
Function : converts a perl object generated from a Google Maps
JSON response to a Geo::Google::Location object
Returns : a Geo::Google::Location object
Args : a member of the $obj->{overlays}->{markers}->[]
anonymous array that you get when you read google's
JSON response and parse it using JSON::jsonToObj()_JSONrenderSkeleton()
Usage : my $perlvariable = _JSONrenderSkeleton();
Function : creates the skeleton of a perl data structure used by
the Geo::Google::Location and Geo::Google::Path for
rendering to Google Maps JSON format
Returns : a mildly complex multi-level anonymous hash/array
perl data structure that corresponds to the Google
Maps JSON data structure
Args : none