Square-Mile Street Network Visualization

The heart of Allan Jacobs’ classic book on street-level urban form and design, Great Streets, features dozens of hand-drawn figure-ground diagrams in the style of Nolli maps. Each depicts one square mile of a city’s street network. Drawing these cities at the same scale provides a revealing spatial objectivity in visually comparing their street networks and urban forms.

We can recreate these visualizations automatically with Python and the OSMnx package, which I developed as part of my dissertation. With OSMnx we can download a street network from OpenStreetMap for anywhere in the world in just one line of code. Here are the square-mile diagrams of Portland, San Francisco, Irvine, and Rome created and plotted automatically by OSMnx:

OSMnx: Figure-ground diagrams of one square mile of Portland, San Francisco, Irvine, and Rome shows the street network, urban form, and urban design in these cities

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OSMnx: Python for Street Networks

OSMnx: New York City urban street network visualized and analyzed with Python and OpenStreetMap dataOSMnx is a Python package for downloading administrative boundary shapes and street networks from OpenStreetMap. It allows you to easily construct, project, visualize, and analyze complex street networks in Python with NetworkX. You can get a city’s or neighborhood’s walking, driving, or biking network with a single line of Python code. Then you can simply visualize cul-de-sacs or one-way streets, plot shortest-path routes, or calculate stats like intersection density, average node connectivity, or betweenness centrality. You can download/cite the paper here.

In a single line of code, OSMnx lets you download, construct, and visualize the street network for, say, Modena Italy:

import osmnx as ox
ox.plot_graph(ox.graph_from_place('Modena, Italy'))

OSMnx: Modena Italy networkx street network in Python from OpenStreetMap Continue reading OSMnx: Python for Street Networks

How to Visualize Urban Accessibility and Walkability

Tools like WalkScore visualize how “walkable” a neighborhood is in terms of access to different amenities like parks, schools, or restaurants. It’s easy to create accessibility visualizations like these ad hoc with Python and its pandana library. Pandana (pandas for network analysis – developed by Fletcher Foti during his dissertation research here at UC Berkeley) performs fast accessibility queries over a network. I’ll demonstrate how to use it to visualize urban walkability. My code is in these IPython notebooks in this urban data science course GitHub repo.

First I give pandana a bounding box around Berkeley/Oakland in the East Bay of the San Francisco Bay Area. Then I load the street network and amenities from OpenStreetMap. In this example I’ll look at accessibility to restaurants, bars, and schools. But, you can create any basket of amenities that you are interested in – basically visualizing a personalized “AnythingScore” instead of a generic WalkScore for everyone. Finally I calculate and plot the distance from each node in the network to the nearest amenity:

Berkeley Oakland California street network walking accessibility and walkability Continue reading How to Visualize Urban Accessibility and Walkability

Map Projections That Lie

How big is Greenland? It’s huge, right? At 836,109 square miles in size, Greenland is the largest island and the 12th largest country on Earth. With only 56,000 people living in that enormous area (80% of which is covered by the world’s only extant ice sheet outside of Antarctica), it is also the least densely populated country on Earth.

You can get a sense of how large Greenland is when you look at a map of the world:

world map mercator projection

It’s huge! Greenland is bigger than the entire continent of Africa! Or is it? The map above uses the common Mercator projection to project the 3-D surface of the Earth onto a 2-D surface suitable for a paper map or an image on your computer screen. But it’s not easy to project the curved surface of a sphere onto a rectangular plane. Compromises must be made. In the case of the Mercator projection, the compromise is that objects’ sizes become increasingly distorted the further they are from the equator. At the poles, the scale and distortion become infinite.

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Off the Beaten Path in Myanmar

myanmar-29I recently had the opportunity to travel across Myanmar for the first time. It’s a fascinating country, only recently emerging from decades of isolation. Travelers here today are greeted with the first few baby steps toward a tourism industry, as well some of the kindest people and most spectacular sights in Asia.

Myanmar is not the easiest country to approach. It remains, effectively, a military dictatorship wracked with corruption and abuse. Government officials control the airlines and hotels for personal profit. Large swaths of eastern Myanmar are dedicated to opium plantations funneling foreign currency into the pockets of powerful officials. Even its name is controversial: many foreign governments still officially recognize only its traditional name, Burma, as a political statement against the authoritarian regime that renamed it Myanmar in 1989. 
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Hong Kong at Night

Hong Kong is a remarkable place. It is the 4th-densest sovereign state or self-governing territory in the world (in 1st place is its neighbor across the delta: Macau). Yet this density is fantastically constrained by the mountains and the sea into narrow, snaking corridors of high-rises wherever the terrain permits. At no time is this unique urban development better seen than at night, when Hong Kong lights up like a carnival.

I took these photos from the top of Victoria Peak on Hong Kong island and from the Tsim Sha Tsui promenade on the Kowloon peninsula, using long exposures of between 3 and 12 seconds.

hong-kong-skyline-night-2 Continue reading Hong Kong at Night

LEED-ND and Neighborhood Livability

I recently co-authored a journal article titled LEED-ND and Livability Revisitedwhich won the Kaye Bock award. LEED-ND is a system for evaluating neighborhood design that was developed by CNU, USGBC, and NRDC. Many of its criteria, particularly site location and neighborhood pattern, accordingly reflect New Urbanist and Smart Growth principles and are inspired by traditional neighborhood design.

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The Inside Field Exam and Urban Complexity

I recently completed my inside field exam, one of the many steps involved in advancing to candidacy. The three professors on your inside field committee send you six questions – a pair per professor – and you are given 72 hours total to answer one question from each pair. The answers are to be in the form of a scholarly article with thorough citations. Long story short, you’ve got to write 30 pages of academic scholarship in three days.

The exam questions themselves are very interesting. The professors construct them based on their reading of your inside field statement, trying to probe areas that might be particularly rich or a bit weak in the statement. Here are the questions I answered:

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How Our Neighborhoods Lost Local Food (And How They Can Get It Back)

Healthy-foodThis post is adapted from an article I wrote in Progressive Planning.

Does food matter in neighborhood design? Should it? The answers to these questions are complicated and obscured by decades of perplexing policy and practice. There are many benefits of good food – that is, food which is healthy, affordable, fair, and sustainable. Proper nourishment has been linked in several studies to better classroom performance. Walkable access to healthy food can reduce America’s growing obesity and diabetes epidemics. Locally-sourced food can reinforce better dietary habits as consumers connect with the value chain and see eating as a more natural process.

The benefits are straightforward, but do most American neighborhoods actually support healthy food access?

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Urban Complexity and the March Toward Qualifying Exams

The Department of City and Regional Planning at UC Berkeley has a rather arduous process for advancing to candidacy in the PhD program. It essentially consists of 6 parts:

  1. Take all the required courses
  2. Produce an inside field statement – a sort of literature review and synthesis explaining the niche within urban planning in which you will be positioning your dissertation research
  3. Complete an outside field – sort of like what a minor was in college
  4. Take an inside field written exam
  5. Produce a defensible dissertation prospectus
  6. Take an oral comprehensive exam covering your inside field, your outside field, general planning theory and history, and finally presenting your prospectus.

Whew. Lots to do this year. The good news is I am currently wrapping up my inside field statement and preparing to take the inside field exam. My topic is generally around complexity theory in urban planning. Here is the working abstract from my statement:

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