NAME
Map::Tube - A very simple perl interface to the London Tube Map.
VERSION
Version 2.02
AWARD
Map::Tube has been granted the "Famous Software Award" by Download.FamousWhy.com on Tue 09 Nov 2010.
http://download.famouswhy.com/map_tube/
SYNOPSIS
B -------- C
/ \ / \
/ \ / \
/ \ / \
A ------ G ------- D
\ / \ /
\ / \ /
\ / \ /
F -------- E
/
/
/
H
\
\
\
I
which can be defined as below:
{ 'A' => ['B','F','G'],
'B' => ['A','C','G'],
'C' => ['B','D','G'],
'D' => ['C','E','G'],
'E' => ['D','F','G'],
'F' => ['A','E','G','H'],
'G' => ['A','B','C','D','E','F'],
'H' => ['F','I'],
'I' => ['H']
}DESCRIPTION
The module intends to provide you as much information as possible from London Tube Map through perl interface. The very first thing anyone would like to know from any map is to find the shortest route between two point. This is exactly what I am trying to solve at the moment. However I would be adding more interesting information very soon. This module covers some of the underground lines managed by Travel for London. It is far from complete and bound to have missing links and incorrect mapping. Please feel free to shout back to me, if you find any error/issue. While trying to find the shortest route, it takes into account the number of stops one has to go through to reach the destination. I do agree, at times, you wouldn't mind going through few extra stops, to avoid changing lines. I might add this behaviour in future. Please note Map::Tube doesn't try to explain Dijkstra's algorithm but to provide a perl interface to the London Tube Map. It covers Bakerloo, Central, Circle, District, DLR, Hammersmith & City, Jubilee, Metropolitan, Northern, Overground, Piccadilly, Victoria and Waterloo & City. Here is the link to the official London Tube Map: http://www.tfl.gov.uk/assets/downloads/standard-tube-map.pdf
CONSTRUCTOR
The constructor expects no parameters. This setup the default node definitions. By default the DEBUG is turned off.
use strict; use warnings;
use Map::Tube;
# Setup the default node with DEBUG turned OFF.
my $map = Map::Tube->new();METHODS
get_shortest_route()
This method accepts FROM and TO node name. It is case insensitive. It returns back the node sequence from FROM to TO.
use strict; use warnings;
use Map::Tube;
# Setup the default node defintion with DEBUG turned OFF.
my $map = Map::Tube->new();
# Find the shortest route from 'Bond Street' to 'Euston'.
my @route = $map->get_shortest_route('Bond Street', 'Euston');get_next_node()
This method accept the current node and list of remaining untouched nodes. It then returns the next node, if possible stay on the same line as the current node's line.
use strict; use warnings;
use Map::Tube;
# This setup the default node ready to be use.
my $map = Map::Tube->new();
# A --- B --- C --- D
# \ /
# \ /
# \ /
# \ /
# E
#
# Suppose the start node is 'A' and the end node is 'D'. Based on the above map
# There are two possible routes either A - B - C - D or A - B - E - D.
# Now lets assume A - B - C - D belongs to Line1 and A - B - E - D belongs to Line2.
#
# Lets assume we have 'C','E' as untouched nodes. and current node is 'B'.
#
# So from node 'B', we could either move to 'B' or 'E', since 'C' belongs to
# Line1 and the parent node of current node is 'A' belongs to Line1, we would
# rather prefer choosing 'C' first as it is on the same Line1.
#
# Therefore, the get_next_node() should return us 'C' from the list ('C','E').
my $node = { 'A' => ['B'],
'B' => ['A','C','E'],
'C' => ['B','D'],
'D' => ['C','E'],
'E' => ['B','D']};
my $line = { 'Line1' => ['A','B','C','D'],
'Line2' => ['B','E','D'] };
# Define user node.
$map->set_node($node);
# Define line.
$map->set_line($line);
# Find the next node from 'B'.
my $next = $map->get_next_node('B', ['C','E']);get_tube_lines()
This method accept node code and returns the line name of the given node code. This applies mainly to the default node definitions. However if user has provided line information then it will use them.
use strict; use warnings;
use Map::Tube;
# This setup the default node ready to be use.
my $map = Map::Tube->new();
# Get tube lines for the node 'Wembley Park'.
my @lines = $map->get_tube_lines('Wembley Park');set_node()
This method accept the node defintion from user. It does some basic check i.e. the node data has to be reference to a HASH and each key has a value which is a reference to an ARRAY. It doesn't, however, checks the mapping currently. Beware if you have any error in mapping, you might see garbage out. Please note key of each node has to be a string.
use strict; use warnings;
use Map::Tube;
# This setup the default node ready to be use.
my $map = Map::Tube->new();
# Define node
my $node = { 'A' => ['B','F','G'],
'B' => ['A','C','G'],
'C' => ['B','D','G'],
'D' => ['C','E','G'],
'E' => ['D','F','G'],
'F' => ['A','E','G','H'],
'G' => ['A','B','C','D','E','F'],
'H' => ['F','I'],
'I' => ['H'],};
# However user can override the node definition.
$map->set_node($node);
# Find the shortest route from 'C' to 'H'
my @route = $map->get_shortest_route('C', 'H');set_default_node()
This method set the default node definition.
use strict; use warnings;
use Map::Tube;
# This setup the default node ready to be use.
my $map = Map::Tube->new();
# Define node
my $node = { 'A' => ['B','F','G'],
'B' => ['A','C','G'],
'C' => ['B','D','G'],
'D' => ['C','E','G'],
'E' => ['D','F','G'],
'F' => ['A','E','G','H'],
'G' => ['A','B','C','D','E','F'],
'H' => ['F','I'],
'I' => ['H'],};
# However user can override the node definition.
$map->set_node($node);
# Find the shortest route from 'C' to 'H'
my @route = $map->get_shortest_route('C', 'H');
# Revert back to the default node definition.
$map->set_default_node();
# Find the shortest route from 'Bond Street' to 'Euston'.
@route = $map->get_shortest_route('Bond Street', 'Euston');get_node()
Returns all the node's map defintions.
use strict; use warnings;
use Map::Tube;
# Setup the default node defintion with DEBUG turned OFF.
my $map = Map::Tube->new();
# Get the node's map definition.
my $node = $map->get_node();get_line()
Returns all the tube line's defintions. For user defined node, it would return line definition provided by the user, if any, otherwise UNDEF.
use strict; use warnings;
use Map::Tube;
# Setup the default node defintion with DEBUG turned OFF.
my $map = Map::Tube->new();
# Get the tube line's definition.
my $line = $map->get_line();set_line()
Set the user defined line defintions.
use strict; use warnings;
use Map::Tube;
# Setup the default node defintion with DEBUG turned OFF.
my $map = Map::Tube->new();
my $node = { 'A' => ['B'],
'B' => ['A','C'],
'C' => ['B','D','F'],
'D' => ['C','E'],
'E' => ['D','F'],
'F' => ['C','E'] };
# Set the user node.
$map->set_node($node);
# Define line.
my $line = { 'Line1' => ['A','B','C','D','E','F'],
'Line2' => ['C','F','E'] };
# Set the user defined line definitions.
$map->set_line($line);get_element()
Returns all the elements i.e. node defintions.
use strict; use warnings;
use Map::Tube;
# Setup the default node defintion with DEBUG turned OFF.
my $map = Map::Tube->new();
# Get all the elements i.e. node definition.
my $element = $map->get_element();get_name()
This method takes a node code and returns its name. If the node belongs to user defined mapping then it simply returns the node code itself.
use strict; use warnings;
use Map::Tube;
# Setup the default node defintion with DEBUG turned OFF.
my $map = Map::Tube->new();
# Get node name for the given node code.
my $name = $map->get_name('BST');set_debug()
This method enables to turn the debug on or off.
use strict; use warnings;
use Map::Tube;
# Setup the default node defintion with DEBUG turned OFF.
my $map = Map::Tube->new();
# Debug is turned on.
$map->set_debug(1);show_map_chart()
This method dumps the map chart used internally to find the shortest route to the STDOUT. This should only be called after get_shortest_route() to get some reasonable data. The map chart is generated by the internal method _process_node() which gets called by the method get_shortest_route(). This method takes no parameter. It has three columns by the title "N" - Node Code, "P" - Path to here and "L" - Length to reach "N" from "P".
use strict; use warnings;
use Map::Tube;
# This setup the default node ready to be use.
my $map = Map::Tube->new();
# Define node
my $node = { 'A' => ['B','F','G'],
'B' => ['A','C','G'],
'C' => ['B','D','G'],
'D' => ['C','E','G'],
'E' => ['D','F','G'],
'F' => ['A','E','G','H'],
'G' => ['A','B','C','D','E','F'],
'H' => ['F','I'],
'I' => ['H'],};
# However user can override the node definition.
$map->set_node($node);
# Find the shortest route from 'C' to 'H'
my @route = $map->get_shortest_route('C', 'H');
# The map chart will have meaningfull data only after you
# have called method get_shortest_route().
$map->show_map_chart();sanity_check()
This method is used for sanity checking of all the data involved in the module. It croaks with appropriate error message if any vital information is missing.
_initialize()
This is an internal method of the module, which sets the default node definition, mapping and line information. This gets called by the method set_default_node() and the constructor new().
_process_node()
This is an internal method of the module, which takes FROM node code only. This assumes all the node definitions are defined and map chart has been initialized.
_initialize_table()
This is an internal method and it simply initialize the map chart. It takes nodes definition as reference to a hash and return the table, which is also reference to a hash.
AUTHOR
Mohammad S Anwar, <mohammad.anwar@yahoo.com>
ACKNOWLEDGEMENTS
BUGS
Please report any bugs or feature requests to bug-map-tube@rt.cpan.org, or through the web interface at http://rt.cpan.org/NoAuth/ReportBug.html?Queue=Map-Tube. I will be notified, and then you'll automatically be notified of progress on your bug as I make changes.
SUPPORT
You can find documentation for this module with the perldoc command.
perldoc Map::TubeYou can also look for information at:
RT: CPAN's request tracker
AnnoCPAN: Annotated CPAN documentation
CPAN Ratings
Search CPAN
LICENSE AND COPYRIGHT
Copyright 2010 Mohammad S Anwar.
This program is free software; you can redistribute it and/or modify it under the terms of either: the GNU General Public License as published by the Free Software Foundation; or the Artistic License.
See http://dev.perl.org/licenses/ for more information.