Sunday, August 19, 2018

The urban landscape of Hong Kong

Johnny Harris (Vox) has filmed a great series of short-videos that helps us understand the urban landscape of Hong Kong. In one of these videos, Johnny talks about how one of the most unaffordable housing markets in the world is driven by government's land-use regulations. The videos also cover the decline of Hong Kong's neon nightscape and even how feng shui shapes the city skyline. There is also a very informative one about the changing relationship between Hong Kong and China. You can check the list of videos below.



Monday, August 13, 2018

Urban Picture

Barcelona at day and night, by the talented Henry Do (ht Architecture)


Saturday, August 11, 2018

Assorted R Packages for Spatial Analysis

  1. RgeoProfile is an R package for carrying out geographic profiling - a technique derived from criminology that uses the spatial locations of linked crimes to infer the home location (or locations) from which the criminal is operating, by Steve LeComber

  2. rayshader is a package for producing hillshaded maps of elevation matrices with raytracing and spherical texture mapping, by Tyler Mogan.

  3. dodgr: fast calculations of pairwise distances on directed graphs in R, by Mark Padgham

  4. rmapshaper: a simple way to simplify shape files, by Andy Teucher

  5. rpostgis: Linking R with a PostGIS Spatial Database, by David Bucklin and Mathieu Basille

  6. osrmr: a wrapper around the OSRM API, a super fast routing engine for OpenStreetMaps, by Adrian Stämpfli-Schmid

  7. stplanr is a package providing various functions and data access for transport research, by Robin Lovelace. This is the core package underneath The Propensity to Cycle Tool

Monday, August 6, 2018

Tuesday, July 31, 2018

PhD Thesis submitted !

After  4 years, 9 months and 18 days  quite some time, I have finally submitted my thesis to the Examination School of Oxford University. The thesis is entitled “Distributive Justice and Transportation Equity: Inequality in accessibility in Rio de Janeiro”. You can read the abstract below.

Thank you Christine Moore , Homero Paltán and Kevin Wheeler for being there for me, literally !



I will soon share the thesis manuscript. For now, here is the abstract:

   Public transport policies play a key role in shaping the social and spatial structure of cities. These policies influence how easily people can access opportunities, including health and educational services and job positions. The accessibility impacts of transport policies thus have important implications for social inequalities and for the promotion of just and inclusive cities. However, in the transportation literature, there is still little theoretically informed understanding of justice and what it means in the context of transport policies. Moreover, few studies have moved beyond descriptive analyses of accessibility inequalities to evaluate how much those inequalities result from transport policies themselves. This is particularly true in cities from the global South, where accessibility and equity have so far remained marginal concerns in the policy realm. 
   This thesis builds on theories of distributive justice and examines how they can guide the evaluation of transport policies and plans. It points to pathways for rigorous assessment of the accessibility impacts of transport policies and it contributes to current discussions on transportation equity. A justice framework is developed to assess the distributional effects of transport policies. This framework is then applied to evaluate recent transport policies developed in Rio de Janeiro (Brazil) in preparation to host sports mega-events, such as the 2014 FIFA World Cup and the 2016 Olympic Games, which included substantial expansion of the rail and Bus Rapid Transit (BRT) infrastructure. This research presents ex-post analyses of the policies implemented between 2014 and 2017 and ex-ante analysis of an as yet unfinished BRT project. It evaluates how the planned transport legacy of those mega-events impacted accessibility to sports venues, healthcare facilities, public schools and job opportunities for different income groups. 
   The results show that there were overall accessibility benefits from the expansion in transport infrastructure between 2014 and 2017, but these were generally offset by the reduction in bus service levels that followed an economic crisis that hit the city after the Olympics. Quasi-counterfactual analysis suggests that, even if the city had not been hit by the economic crisis, recent transport investments related to mega-events would have led to higher accessibility gains for wealthier groups and increased inequalities in access to opportunities. Results suggest that those investments had, or would have had, greater impact on inequalities of access to jobs than in access to schools and healthcare facilities. The evaluation of the future accessibility impacts of the unfinished BRT corridor, nonetheless, indicates that such project could significantly improve access to job opportunities for a large share of Rio’s population, particularly lower-income groups. Spatial analysis techniques show that the magnitude and statistical significance of these results depend on the spatial scale and travel time threshold selected for cumulative opportunity accessibility analysis. These results demonstrate that the ad-hoc methodological choices of accessibility analysis commonly used in the academic and policy literature can change the conclusions of equity assessments of transportation projects.



Monday, July 23, 2018

Mapping the diversity of population ageing across Europe with a ternary colour scheme

Ilya Kashnitsky and Jonas Schöley have recently published this correspondence in The Lancet where they show a very clever way to visualize the spatial heterogeneity of population age structures using choropleth map with ternary colour scheme. The data wrangling was done in R, and the code to replicate get the data and replicate the figure is available on Github.

Needless to say that, if you're interested in demography, R and data, you should be following the work and twitter accounts of Ilya and Jonas.

click on to image to enlarge it

image credit: Ilya Kashnitsky and Jonas Schöley.

Monday, July 16, 2018

Tuk Tuk Uber

While I was in Dar es Salaam a few weeks ago, Manuel Santana drew my attention to these three-wheeler tuk tuks with "Uber" written at the back (photo below). At first, I thought that was just a marketing strategy or perhaps a funny joke. Little did I knew that those tuk tuks are regular service providers registered with Uber. This is quite telling of Uber's flexibility to adapt to the particularities of each local context (for better or worse).

ps. In case you're wondering, we didn't take Tuk Tuk Uber... We wouldn't be able to squeeze four people in a Tuk Tuk after dinner.



photo credit: Manuel Santana

Sunday, July 15, 2018

Friday, July 6, 2018

Chart of the day: The rich cultural diversity of 200 Years of US immigration

The accumulated history of US immigration visualized as rings in a growing tree trunk. The chart was created by Pedro M. Cruz and John Wihbey using IPUMS data. It's the first time I see migration data depicted in this way and it does a really terrific job drawing attention to composition diversity and population history.

UPDATE: Leah Boustan has just drawn my attention on Twitter for an important shortcoming of this cart. Leah has rightly pointed that:
"This graphic is great for visualizing changes in composition of immigrant flow to US over time but obscures dramatic fluctuations in magnitude. ~1 mil immigrants entered per year in 1910, down to 100k by 1930 — yet the concentric circles makes it seem like entry grows over time"