Thursday, December 31, 2015

Thursday, December 24, 2015

Tuesday, December 22, 2015

Quote of the Day: Anxiety

Friday, December 18, 2015

How the most segregated cities in the US and Brazil compare

Using the Dissimilarity Index to measure racial segregation, this his is how the most segregated cities in the US and Brazil compare. A remarkable difference, which I would love to understand more before making any comments.

This chart comes from a great piece on racial segregation in Brazil [only in Portuguese], via Maurício Santoro

[image credit: Nexo, Daniel Mariani, Murilo Roncolato, Simon Ducroquet e Ariel Tonglet]

Tuesday, December 15, 2015

Journal Spatial Demography

I'm not sure if I have mentioned here in the blog the relatively new journal Spatial Demography. In any case, it promises to be a great journal for population studies, with an incredible editoral board and some very interesting publications.

The journal also brings some more practical publications, like how to use R for Spatial Analysis (parts 1 and 2) and how to Measure Residential Segregation, these two tutorials authored by Corey Sparks.

Monday, December 14, 2015

Urban Picture

A nice little piece of Rio, by Flavio Veloso

Soundtrack: Black Rio

Wednesday, December 9, 2015

Monday, December 7, 2015

Brazil Racial Dotmap

A few weeks ago, we made a blog post about the racial dot map of Rio de Janeiro, inspired by Bill Rankin's maps on segregation and the racial dot map of the US.

Fábio Vasconcellos has just pointed out on his twitter to the Racial Dotmap of Brazil, with 190 million dots distributed distributed within Brazilian census tracts. The map was created using a Python script in QGIS, which is available on GitHub.

Each dot represents a person. Blue dots represent white people, while green and red dots represent brown and black people.
[credit: Pata]

Here is the US racial dot map. The two maps are not 100% comparable since the racial categories used in both maps are not exactly the same, but they give a rough comparison of how white and black populations are spatially distributed in both countries.

[credit: Dustin Cable]

India expected to overtake China′s population by 2026

Aron Strandberg has a great series of tweets on demographic trends.

Nigeria is also expected to overtake the US population at some point after 2050.

Saturday, December 5, 2015

32 Laps around the Sun

Hi all,

it's my birthday today. I'm completing my 32nd lap around the Sun, so I just dropped by to say thanks. Life has been wonderful and I'm truly grateful for being so lucky about so many things, specially about having so many amazing people around me.

image credit: ?

Friday, December 4, 2015

Tracking global bicycle ownership patterns

 Weighted mean percentage household bicycle ownership

click on the image to enlarge it

This map comes from a new paper:  Oke, O., et al. (2015). Tracking global bicycle ownership patterns. Journal of Transport & Health.

Over the past four decades, bicycle ownership has been documented in various countries but not globally analyzed. This paper presents an effort to fill this gap by tracking household bicycle possession. First, we gather survey data from 150 countries and extract percentage household bicycle ownership values. Performing cluster analysis, we determined four groups with the weighted mean percentage ownership ranging from 20% to 81%. Generally, bicycle ownership was highest in Northern Europe and lowest in West, Central and North Africa, and Central Asia. We determine worldwide household ownership patterns and demonstrate a basis for understanding the global impact of cycling as a sustainable transit mode. Furthermore, we find a lower-bound estimate of the number of bicycles available to the world׳s households. We establish that at the global level 42% of households own at least one bicycle, and thus there are at least 580 million bicycles in private household ownership. Our data are publicly available and amenable for future analyses.

The data and supporting code (in Python) are available here.


Thursday, December 3, 2015

Thursday, November 26, 2015

Revise and Resubmit

How motivated I am with a 'revise/resubmit' decision after six months of submitting the paper.

credit: Kostas Siozios

Wednesday, November 25, 2015

Thursday, November 19, 2015

Exploring 1.1 Billion NYC Taxi and Uber Trips

Todd Schneider has posted a thorough analysis of 1.1 Billion NYC Taxi and Uber Trips where he explores the city's neighbourhoods, night-life, airport traffic etc. You can replicated all that using publicly available data, R, PostgreSQL and PostGIS. GitHub repository here.

Tuesday, November 17, 2015

Programming Music with Punched Cards

I've just learned this 'instrument' is called a fairground organ. This is as hipster as you can get with coding.

ps. in case you're under 30, there is a high chance you don't know what a Punched Card is. You might like reading this.

Monday, November 16, 2015

Walking Tube map, or the most important map when you are in London

Map of the  last  week: Transport for London (TFL) has recently published new map that shows how long it takes to walk between stations on the London Tube (a.k.a. underground or subway).

Saturday, November 14, 2015

Thursday, November 12, 2015

Spatial + Temporal patterns of bike sharing in Moscow

Urbica (a design company based in Moscow) have done a great job in analyzing the spatial and temporal patterns of bike sharing in Moscow (ht Andrey Karmatsky). To our delight, their source code is available on GitHub.

I would highly recommend you to  procrastinate on  check their website. You can also read a nice summary of their results here.

ps. You might want to check a few related links at the bottom of this post.

Quote of the Day

"Each of us knows that some of our opinions are wrong, and none of us know which they are. For if we did, they would not be our opinions."
John Stuart Mill

Monday, November 9, 2015

Measuring segregation using patterns of daily travel behavior

Mental note: New paper in my reading list. Big names from transport/geography studies pushing the boundaries of segregation research by going beyond the debate on residential segregation. 

Farber, S., O'Kelly, M., Miller, H. J., & Neutens, T. (2015). Measuring segregation using patterns of daily travel behavior: A social interaction based model of exposure. Journal of Transport Geography, 49, 26-38.

Recent advances in transportation geography demonstrate the ability to compute a metropolitan scale metric of social interaction opportunities based on the time-geographic concept of joint accessibility. The method we put forward in this article decomposes the social interaction potential (SIP) metric into interactions within and between social groups, such as people of different race, income level, and occupation. This provides a novel metric of exposure, one of the fundamental spatial dimensions of segregation. In particular, the SIP metric is disaggregated into measures of inter-group and intra-group exposure. While activity spaces have been used to measure exposure in the geographic literature, these approaches do not adequately represent the dynamic nature of the target populations. We make the next step by representing both the source and target population groups by space–time prisms, thus more accurately representing spatial and temporal dynamics and constraints. Additionally, decomposition of the SIP metric means that each of the group-wise components of the SIP metric can be represented at zones of residence, workplace, and specific origin–destination pairs. Consequently, the spatial variation in segregation can be explored and hotspots of segregation and integration potential can be identified. The proposed approach is demonstrated for synthetic cities with different population distributions and daily commute flow characteristics, as well as for a case study of the Detroit–Warren–Livonia MSA.

Thursday, November 5, 2015

The Racial Dot Map of Rio de Janeiro

A while ago, I've posted some of Bill Rankin's maps on segregation for different cities in the USA. Those maps got a lot public attention because they were innovative in the way they depicted racial segregation by  representing each individual as one single dot and each ethnicity as a different color. Needless to say this approach gives a much better visual effect than traditional choropleth maps.

Inspired in Rankin's map, Nicolau de Gusmão (geography student from Sao Paulo) has created in a racial dot map of Rio. Pretty neat. He used data from the 2010 population census and he created the map using QGIS. His post is written in Portuguese, but you don't need to speak the language to appreciate the maps and get your own conclusion about segregation levels in Rio.

The difference between economic migrants and refugees

Monday, October 12, 2015

Build and they will come, or The Black Hole Theory of Highway Investment

These incredible scenes reminded me of a quote by Plane (1995) about the Black Hole Theory of Highway Investment:
"Initial investments in improved highway facilities result in greater ease of travel and hence altered travel patterns, including an increase in average trip length and in the number of trips being made. Over time, as shown in Figure 18.1, this increased demand stimulated by the initial investment in increased transport supply fuels the need for even more facilities, and the feedback process repeat itself. This familiar phenomenon has been called the black-hole theory because some people claim that investing in highways is like throwing money into a black hole" (Plane, 1995 p.439)

photo credit: Rafael Pereira

  • Plane, D. A. (1995). Urban transportation: policy alternatives. In Hanson & Giuliano (Eds.) The geography of urban transportation. (2nd ed.) New York ; London: Guilford Press.

Sunday, October 11, 2015

Thursday, October 8, 2015

Compare the subway systems of Rio and Shanghai between 1979 and 2014

A nice GIF comparing the expansion of the subway systems in Rio de Janeiro and Shanghai between 1979 and 2014.

[image credit: ? via Lucas Gaspar on FB]

We've seen this before, but I couldn't resist posting this GIF (it covers a wider time span, it is quite straightforward and I love gifs

The hidden inequality of who dies in car crashes

Emily Badger has written an interesting piece on The Washington Post covering a recent study that discuss socioeconomic inequalities in car crashes in the US between 1995 and 2010.

Friday, October 2, 2015

off-topic: feeling of the day

When you're arguing with someone online
source: somewhere on facebook

Thursday, September 24, 2015

How much do Americans drive compared to other countries?

This comes from a new report published by LSE Cities. Commentary  by Richard Florida and Aria Bendix here.

Annual vehicle kilometres per person against wealth levels: 1970-2008

click on the image to enlarge it

Wednesday, September 23, 2015

Urban Picture

Delirious New York, by Ezra Stoller.

Headquarters of the United Nations, NYC

soundtrack: one of my favourites from Kermit

Saturday, September 19, 2015

The Human Hemisphere

We have seen Bill Rankin's inventive map of the World Population Distribution by lat long. More recently Bill has come with other ways of thinking our hemispheres. Here is my favourite one.

ps. On a related topic, here is map showing how geographically unbalanced the distribution of the world population is.

[image credit: Bill Rankin, 2015]

Redefining Urban Futures

Nice presentation by Kent Larson summarizing some of the projects they have been developing at MIT Media Lab and that are contributing to redefine the future of our cities, in some way.

I wouldn't say these ideas are new, revolutionary or even disruptive in a way that will solve the most pressing issues in most cities for every one. However, the work of Kent and his team make an enormous difference in bringing these ideas closer to reality.

Friday, September 18, 2015

Before there was ggplot

Before Hadley Wickham was born, when there was no ggplot, this is how people used to create maps using small multiples (nice example here).

Results of the US Presidential Election from 1789 to 1876, published in 1877

Wednesday, September 16, 2015

Transport disruptions, big data and travel behavior

A new discussion paper shows how a strike in the underground system of London could actually improve general welfare and make individuals' travel behavior more efficient. (via Tyler Cowen).

Larcomy, S., Rauch, F., Willems, T. The benefits of forced experimentation: striking evidence from the London underground network. University of Oxford. Department of Economics Discussion Paper Series (Ref: 755 )
Abstract: We estimate that a significant fraction of commuters on the London underground do not travel their optimal route. Consequently, a tube strike (which forced many commuters to experiment with new routes) taught commuters about the existence of superior journeys -- bringing about lasting changes in behaviour. This effect is stronger for commuters who live in areas where the tube map is more distorted, thereby pointing towards the importance of informational imperfections. We argue that the information produced by the strike improved network-efficiency. Search costs are unlikely to explain the suboptimal behaviour. Instead, individuals seem to under-experiment in normal times, as a result of which constraints can be welfare-improving.

The researchers examined 20 days' worth of anonymised Oyster card data, containing more than 200 million data points, in order to see how individual tube journeys changed during the London tube strike in February 2014.


Tuesday, September 15, 2015

The shifting patterns of how Londoners live and work

Here is an interesting piece about passenger trends in London’s Underground system since 2001 and how this piece of information helps us better understand how the city's economy is changing (I saw this via Iain Docherty).

One obvious change in passenger patterns captured by this chart shows the notion of 'peak time' has widened over the past fifteen years or so. As the article suggest, this is likely a reflex of some of the changes observed both in the labor market (with the increase in the number of workers that are self-employed and have more flexible time shifts) and in the housing market, where the prohibitive housings costs of London are pushing people farther from the city.

Wednesday, September 9, 2015

Returners and explorers dichotomy in human mobility

Pappalardo, L., Simini, F., Pedreschi, D., Barabasi, L. et al. (2015). Returners and explorers dichotomy in human mobility. Nature Communications, 6. doi:10.1038/ncomms9166

The availability of massive digital traces of human whereabouts has offered a series of novel insights on the quantitative patterns characterizing human mobility. In particular, numerous recent studies have lead to an unexpected consensus: the considerable variability in the characteristic travelled distance of individuals coexists with a high degree of predictability of their future locations. Here we shed light on this surprising coexistence by systematically investigating the impact of recurrent mobility on the characteristic distance travelled by individuals. Using both mobile phone and GPS data, we discover the existence of two distinct classes of individuals: returners and explorers. As existing models of human mobility cannot explain the existence of these two classes, we develop more realistic models able to capture the empirical findings. Finally, we show that returners and explorers play a distinct quantifiable role in spreading phenomena and that a correlation exists between their mobility patterns and social interactions.
[image credit: Pappalardo et al. 2015]

Tuesday, September 8, 2015

The recent story of my life

I saw this via Arthur Charpentier, who has remarkably good twitter and blog you might like.

[image credit: the unmistakable xkcd]

Friday, September 4, 2015

Where Are the Syrian Refugees Today?

Hans Rosling (aka the Mick Jagger of statistics) in an informative three-minute video about the Syrian Refugees.

Thursday, August 27, 2015

Data visualization with R: geographic networks

I just bumped into this blog from a team at SNAP, where Matthew Leonawicz and his colleagues share some great data visualizations they've been creating with R (and some code snippets). Here are two nice examples of geographic networks on a flat map and on a 3D model of the Earth

This is very similar to the work of James Cheshire (UCL) on mapping the World’s Biggest Airlinesglobal migration and commuting patterns. Neat stuff. I've just added their blog to my feedly

[image credit: Matthew Leonawicz]

Quote of the Day

"The social sciences makes something everyone understands but no one is interested in and turns it into something no one understands and everyone seems interested in." 
(Tony King on a lecture titled "The Tale of Three Cities") ht Kelsi Nagy 

Tuesday, August 25, 2015

The Globe of Economic Complexity

The Atlas of Economic Complexity is a project born from the collaboration between Cesar Hidalgo (MIT) and Ricardo Hausmann (Harvard). The Atlas has an online tool with interactive chars and maps that enables users to visualize a country’s total trade, track how these dynamics change over time and explore growth opportunities for more than a hundred countries worldwide.

More recently, the project has resealed a new visualization tool, the Globe of Economic Complexity (created by Owen Cornec and Romain Vuillemot.). The Start Intro is quite hypnotic, perfect for a few hours of curious procrastination. 

Tuesday, August 18, 2015