raphadasilva / osmnx

Python for street networks: retrieve and construct spatial geometries and street networks from OpenStreetMap.

Home Page:http://geoffboeing.com/2016/11/osmnx-python-street-networks/

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OSMnx

Python for street networks

Retrieve and construct spatial geometries and street networks from OpenStreetMap. Full overview.

OSMnx is a Python 2/3 library that lets you download spatial geometries and construct, project, visualize, and analyze street networks from OpenStreetMap's APIs. Users can download and construct walkable, drivable, or bikable urban networks with a single line of Python code, and then analyze and visualize them:

import osmnx as ox
G = ox.graph_from_place('Berkeley, California', network_type='drive')
stats = ox.basic_stats(G)
ox.plot_graph(G)

For a quick demo overview of OSMnx, see this demo notebook.

Installation

pip install osmnx

If you are on Windows, install geopandas and its dependencies before pip installing OSMnx.

How to use OSMnx

Create place boundary shapefiles from OpenStreetMap

OSMnx lets you download spatial "place boundary" geometries from OpenStreetMap (for cities, counties, states, countries, boroughs, etc.), save them to shapefiles, project them, and plot them. For example, to retrieve, construct, and save a shapefile of Berkeley's administrative boundary:

city = ox.gdf_from_place('Berkeley, California')
ox.save_gdf_shapefile(city)

For a more in-depth demonstration of creating these shapefiles, see this notebook.

Download and construct street networks

OSMnx lets you download street network data and build topologically-corrected street networks, project to UTM and plot the networks, and save the street network as SVGs, GraphML files, or shapefiles for later use. The street networks are directed and preserve one-way directionality. API responses are cached locally so OSMnx doesn't have to request the same data from the API multiple times, saving bandwidth and increasing speed.

For a more in-depth demonstration of creating street networks, see this notebook.

You can download a street network by providing OSMnx any of the following (demonstrated in the examples below):

  • a bounding box
  • a lat-long point plus a distance (either distance along the network, or cardinal)
  • an address plus a distance (either distance along the network, or cardinal)
  • a place name or list of place names (for OSMnx to automatically geocode and get the boundary of)
  • a polygon of the desired street network's boundaries

You can also specify several different network types:

  • drive - get drivable public streets (but not service roads)
  • drive_service - get drivable streets, including service roads
  • walk - get all streets and paths that pedestrians can use (this network type ignores one-way directionality)
  • bike - get all streets and paths that cyclists can use
  • all - download all non-private OSM streets and paths
  • all_private - download all OSM streets and paths, including private-access ones

Correct and simplify street network topology

Simplification is normally done by OSMnx automatically under the hood, but we can break it out to see how it works. OpenStreetMap nodes include intersections, but they also include all the points along a single block where the street curves. The latter are not nodes in the graph theory sense, so we remove them algorithmically and consolidate the set of edges between "true" network nodes into a single edge, but retain the actual spatial geometry. There are two simplification modes, strict and non-strict. The main difference is that unlike strict mode, non-strict mode allows simplification to an "expansion graph". For a more in-depth demonstration of topological simplification with OSMnx, see this notebook.

Save street networks to disk

OSMnx allows users to save street networks to disk as shapefiles to work with in GIS software, as GraphML files to work with in Gephi or NetworkX, and as SVG files to work with in Illustrator. It also allows you to save place boundary geometries as shapefiles. For more examples of saving and loading networks to/from disk, see this notebook.

Analyze and visualize street networks

OSMnx allows you to calculate origin-destination routes along the network and quickly visualize them. You can easily visualize one-way streets, cul de sacs, high/low connectivity intersections, etc. OSMnx provides built-in capabilities to quickly calculate spatial network metrics like intersection density, average intersection degree, edge density, average street segment length, clustering coefficients, betweenness centrality, etc. For more examples of analyzing street networks with OSMnx, see this notebook

For a more complete overview of OSMnx, read this.

Download/cite the paper here.

About

Python for street networks: retrieve and construct spatial geometries and street networks from OpenStreetMap.

http://geoffboeing.com/2016/11/osmnx-python-street-networks/

License:MIT License


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