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Map-Metro-0.1804
River stage two • 19 direct dependents • 19 total dependents
/ Map::Metro

NAME

Map::Metro - Public transport graphing

 

SYNOPSIS

    # Install a map
    $ cpanm Map::Metro::Plugin::Map::Stockholm

    # And then
    my $graph = Map::Metro->new('Stockholm', hooks => ['PrettyPrinter'])->parse;

    my $routing = $graph->routing_for('Universitetet', 'Kista');

prints

    From Universitetet to Kista
    ===========================

    -- Route 1 (cost 15) ----------
    [   T14 ] Universitetet
    [   T14 ] Tekniska högskolan
    [   T14 ] Stadion
    [   T14 ] Östermalmstorg
    [   T14 ] T-Centralen
    [ * T11 ] T-Centralen
    [   T11 ] Rådhuset
    [   T11 ] Fridhemsplan
    [   T11 ] Stadshagen
    [   T11 ] Västra skogen
    [   T11 ] Solna centrum
    [   T11 ] Näckrosen
    [   T11 ] Hallonbergen
    [   T11 ] Kista

    T11  Blue line
    T14  Red line

    *: Transfer to other line
    +: Transfer to other station

DESCRIPTION

The purpose of this distribution is to find the shortest unique route/routes between two stations in a transport network.

Methods

new($city, hooks => [])

$city

The name of the city you want to search connections in. Mandatory, unless you are only going to call "available_maps".

$hooks

Array reference of Hooks that listens for events.

parse()

Returns a Map::Metro::Graph object containing the entire graph.

available_maps()

Returns an array reference containing the names of all Map::Metro maps installed on the system.

What is a unique path?

The following rules are a guideline:

If the starting station and finishing station...

...is on the same line there will be no transfers to other lines.

...shares multiple lines (e.g., both stations are on both line 2 and 4), each line constitutes a route.

...are on different lines a transfer will take place at a shared station. No matter how many shared stations there are, there will only be one route returned (but which transfer station is used can differ between queries).

...has no shared stations, the shortest route/routes will be returned.

MORE INFORMATION

Map::Metro::Graph - How to use graph object.

Map::Metro::Plugin::Map - How to make your own maps.

Map::Metro::Hook - How to extend Map::Metro via hooks/events.

Map::Metro::Cmd - A guide to the command line application.

Map::Metro::Graph::Connection - Defines a MMG::Connection.

Map::Metro::Graph::Line - Defines a MMG::Line.

Map::Metro::Graph::LineStation - Defines a MMG::LineStation.

Map::Metro::Graph::Route - Defines a MMG::Route.

Map::Metro::Graph::Routing - Defines a MMG::Routing.

Map::Metro::Graph::Segment - Defines a MMG::Segment.

Map::Metro::Graph::Station - Defines a MMG::Station.

Map::Metro::Graph::Step - Defines a MMG::Step.

Map::Metro::Graph::Transfer - Defines a MMG::Transfer.

Hierarchy

The following is a conceptual overview of the various parts of a graph:

At first, the map file is parsed. The four types of blocks (stations, transfers, lines and segments) are translated into their respective object.

Next, lines and stations are put together into LineStations. Every two adjacent LineStations are put into two Connections (one for each direction).

Now the network is complete, and it is time to start traversing it.

Once a request to search for paths between two stations is given, we first search for the starting Station given either a station id or station name. Then we find all LineStations for that station.

Then we do the same for the destination station.

And then we walk through the network, from LineStation to LineStation, finding their Connections and turning them into Steps, which we then add to the Route.

All Routes between the two Stations are then put into a Routing, which is returned to the user.

PERFORMANCE

During development of the Berlin map it was discovered that performance on large maps suffered badly.

One stopgap measure to deal with this is to use Sereal to serialize the graph object. Included are two commands, serealize and deserealize. On my machine the time spent searching for a route is reduced by 50-85%. Larger maps, larger savings. It is currently not possible to add hooks to serealizing graphs; the deserealize command works as if PrettyPrinter was attached.

STATUS

This is somewhat experimental. I don't expect that the map file format will break, but it might be extended. Only the documented api should be relied on, though breaking changes might occur.

For all maps in the Map::Metro::Plugin::Map namespace (unless noted):

These maps are not an official source. Use accordingly.
Each map should state its own specific status with regards to coverage of the transport network.

COMPATIBILITY

Currently only Perl 5.20+ is supported.

Map::Tube works with Perl 5.6.

Included in this distribution is a script to convert Map::Metro maps into Map::Tube maps, if Map::Tube misses one you need.

BUGS & ISSUES

The repository and issue tracker is at: https://github.com/Csson/p5-Map-Metro

SEE ALSO

Map::Tube

AUTHOR

Erik Carlsson <info@code301.com>

COPYRIGHT

Copyright 2014 - Erik Carlsson

LICENSE

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