Mander

A Python package and command line utility for calculating compactness metrics of electoral districts.

Example

What scores are available?

import mander
mander.getListOfScores()

Getting scores for GeoJSON:

import mander

geojson_data = """{ "type": "FeatureCollection", "features": [{"type": "Feature","properties": {},"geometry": { "type": "Polygon", "coordinates": [ [ [ -30.585937499999996, 27.68352808378776 ], [ -2.8125, 27.68352808378776 ], [ -2.8125, 46.800059446787316 ], [ -30.585937499999996, 46.800059446787316 ], [ -30.585937499999996, 27.68352808378776 ] ] ] } } ] }"""

mander.getScoresForGeoJSON(geojson_data)

Augmenting an existing shapefile with compactness scores:

import mander
mander.augmentShapefileWithScores("us_electoral_districts.shp")

Compactness Metrics

Compactness scores are calculated using the underlying compactnesslib a list of the scores available and how they are calculated is available here.

Developer Setup

Requirements:

• Python 2.7
• pip
• A compiler that supports C++ 11.
  • If using GCC, must use version 4.9 or greater.

Recommended

• virtualenv

Steps:

• Fork this repo

• Clone your fork

  git clone git@github.com:YOUR_USERNAME_HERE/python-mander.git
  

• Add the original repo as a remote

  git remote add upstream git@github.com:gerrymandr/python-mander.git
  

• This project depends upon a C++ library sourced from a git submodule. Initialize and update the git submodule.

  git submodule init
  git submodule update
  

• Optionally create and activate a Python virtual environment. On Linux or Mac

  virtualenv env
  source env/bin/activate
  

  On Windows

  virtualenv env
  env\Scripts\activate
  

  On any platform, you may exit the virtual environment by running

  deactivate
  

• Install the dependencies

  pip install -r requirements.txt
  

• Build the project

  python setup.py build
  

  • If you need to specify a C compiler other than the default one on your system, you may add an inline environment variable CC and set it to the other compiler. For example, on a system with both gcc 4 and gcc 7 installed:

    CC=gcc-7 python setup.py build
    

Credits

This package was created for the Metric Geometry And Gerrymandering Group as part of a hack-a-thon on August 10-11, 2017.