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Network Scenario Generator (GeNet)

DOI

Table of Contents

Overview

GeNet provides tools to represent and work with a multi-modal transport network with public transport (PT) services. It is based on MATSim's representation of such networks. The underlying network available to PT services (roads, railways, but also ferry/flight connections) uses a networkx.MultiDiGraph with additional methods for 'links' which are unique in genet.Network (networkx.MultiDiGraph accepts multiple edges between the same from and to node pair; referring to an edge in networkx.MultiDiGraph and genet.Network has the same effects, i.e. the result is a dictionary indexed by the multi edge index). The PT services are represented through genet.Schedule class which relies on other genet classes: the Schedule relies on a list of genet.Service's, which in turns consists of a list of genet.Route's. Each Route class object has an attribute stops which consists of genet.Stops objects. The Stops carry spatial information for the PT stop.

The goal of GeNet is to:

  • Provide a formalised in-memory data structure for representing a multi-modal network with a PT service
  • Enable using the data structure for tasks such as generating auxiliary MATSim files e.g. Road Pricing
  • Simplify the process of modifying a network and provide simple change log to track the differences between the input and output networks.
  • Provide validation methods to check for simple errors such as: whether a Route has more than one Stop or that the underlying graph doesn't have any dead-ends or sources (a place which you can leave but cannot get back to).

Setup

To run pre-baked scripts that use GeNet in a number of different scenarios you can use docker, which will save you the work of installing GeNet locally:

Using Docker

Docker is the recommended way to use GeNet if you do not plan to make any code changes.

Build the image

docker build -t "genet" .

Running a container with a pre-baked script

docker run genet reproject_network.py -h

usage: reproject_network.py [-h] -n NETWORK [-s SCHEDULE] [-v VEHICLES] -cp
                            CURRENT_PROJECTION -np NEW_PROJECTION
                            [-p PROCESSES] -od OUTPUT_DIR

Reproject a MATSim network

optional arguments:
  -h, --help            show this help message and exit
  -n NETWORK, --network NETWORK
                        Location of the network.xml file
  -s SCHEDULE, --schedule SCHEDULE
                        Location of the schedule.xml file
  -v VEHICLES, --vehicles VEHCILES
  							  Location of the vehicles.xml file
  -cp CURRENT_PROJECTION, --current_projection CURRENT_PROJECTION
                        The projection network is currently in, eg.
                        "epsg:27700"
  -np NEW_PROJECTION, --new_projection NEW_PROJECTION
                        The projection desired, eg. "epsg:27700"
  -p PROCESSES, --processes PROCESSES
                        The number of processes to split computation across
  -od OUTPUT_DIR, --output_dir OUTPUT_DIR
                        Output directory for the reprojected network

Otherwise, you can install genet as a python package, in your base installation of python or a virtual environment. Run the pre-baked scripts, write your own scripts or use IPython shell or Jupyter Notebook to load up a network, inspect or change it and save it out to file. Check out the wiki pages and example jupyter notebooks for usage examples.

Installation as a Python Package

Note: if you plan only to use GeNet rather than make code changes to it, you can avoid having to perform any local installation by using GeNet's Docker image. If you are going to make code changes, or you don't want to use Docker for some reason...

Native dependencies

GeNet uses some Python libraries that rely on underlying native libraries for things like geospatial calculations and linear programming solvers. Before you install GeNet's Python dependencies, you must first install these native libraries.

A note on the mathematical solver

Note: The default CBC solver is pre-installed inside GeNet's Docker image, which can save you some installation effort

To use methods which snap public transit to the graph, GeNet uses a mathematical solver. If you won't be using such functionality, you do not need to install this solver. Methods default to CBC, an open source solver. Another good open source choice is GLPK. The solver you use needs to support MILP - mixed integer linear programming.

Installing the native dependencies

The commands for installing the necessary native libraries vary according to the operating system you are using, for example:

OS Commands
Mac OS brew install spatialindex
brew install gdal --HEAD
brew install gdal
brew tap coin-or-tools/coinor
brew install coin-or-tools/coinor/cbc
Ubuntu sudo apt install libspatialindex-dev
sudo apt install libgdal-dev
sudo apt install coinor-cbc

Install dev prereqs

(Use equivalent linux or Windows package management as appropriate for your environment)

brew install python3.7
brew install virtualenv

Install Python dependencies

Create and activate a Python virtual environment

virtualenv -p python3.7 venv
source venv/bin/activate

Install GeNet in to the virtual environment

Finally install GeNet's Python dependencies

pip install -e .

Install Kepler dependencies

Please follow kepler's installation instructions to be able to use the visualisation methods. To see the maps in a jupyter notebook, make sure you enable widgets.

jupyter nbextension enable --py widgetsnbextension

Developing GeNet

We welcome community contributions to GeNet; please see our guide to contributing and our community code of conduct. If you are making changes to the codebase, you should use the tools described below to verify that the code still works. All of the following commands assume you are in the project's root directory.

Unit tests

python -m pytest -vv tests

Generate a unit test code coverage report

To generate an HTML coverage report at reports/coverage/index.html:

./bash_scripts/code-coverage.sh

Lint the python code

./bash_scripts/lint-check.sh

Smoke test the Jupyter notebooks

./bash_scripts/notebooks-smoke-test.sh