After a first super succesful session in May 2023, from which we developed a package for radial analysis with the team of Rouen (UMR Idees), Port-Louis (Morbihan, France) will welcome our 2nd coding retreat from February 26th to March 1st.

The retreat is aimed as a team building moment where uni.lu geographers and associated researchers spend time together consolidating their code.

This is mostly an R spatial training, peppered with some Py spatial analytics.

Rationale: we do all have our “own” pieces of code on our personal machines, on a server and/ on our own Git repos, which we fine tune along various projects and need. Then we quickly discover other colleagues have done similar, sometimes better, would benefit from similar lines, or, when reproducing, that some parts do not lead to the exact same results for some reasons (parameters, cut-offs, pre-processing of data,…)

In view of (i) reproducibility, (ii) improving, and (iii) sharing our codes, the retreat is a moment to take stock, compare and develop further our scripts and data.

The program is super simple:

• Intense mornings: 8AM to 2PM Monday to Friday including a quick sandwich lunch,
• Some more relax time up to 4.30PM (a walk outside before sunset)
• And further reading/correcting in the evening 5PM-7PM before enjoying a creperie or a nice
• … starting anew the next day…

For the venue, we joint-venture with the Gîtes de Kerouzec (https://gitesdekerouzec.fr/) so we are housed together, and live for and eat for coding 24/7 (well…24/5) while enjoying a view, a beach and a small but fully serviced town where all our needs are fulfiled in under 5min walk! No time wasted!

Organizer: Geoffrey Caruso, University of Luxembourg.

Venue: 5 Place au Bois, 56290 Port-Louis FR

Abstract

Air pollution is of increasing concern to urban residents and urban planners are struggling to find interventions which tackle the trade‐off between environmental, health, and economic impacts arising from this. We analyze within a spatially explicit theoretical residential choice model how different urban interventions can reduce exposure to endogenous traffic‐induced air pollution at residential locations. We model a city of fixed population size, where households are averse to localized pollution and examine how a flat commuting tax, an urban growth boundary, a cordon toll, and the optimal distance‐based tax compare to an urban scenario without any planner’s intervention. We find that an urban intervention to optimally address exposure concerns needs to achieve steep density gradients near the urban fringe and flat gradients near the center. We show the deficiencies of the alternative interventions to achieve optimal population distributions within the city and in a scenario where peoples’ aversion to pollution increases. We then discuss these interventions in light of resulting spatial patterns of exposure and spatial equity that is households’ assessment of their own exposure to air pollution relative to their responsibility for the exposure of others depending on their spatial location within the city. Our results show that, when equity is also a concern, compensations are needed from households who live in the periphery and our simulations suggest that a cordon toll can then achieve a more balanced outcome.

https://doi.org/10.1111/gean.12288

HUB #1 will have some focus on cities and air pollution with 2 inputs, by Yufei Wei and Hichem Omrani. See below.

When? 22nd of Oct 2019 14h00-16h00. Where? Map Room (next to GIS room) 1st floor MSH, Belval.

Yufei Wei : Scaling of urban heat island and nitrogen dioxide with urban population: a meta-analysis.

In this research, at the beginning a qualitative synthesis is performed to collect literature introducing the relations of urban heat island intensity and nitrogen dioxide concentration with urban population. We then find and validate the linearity of urban heat island intensity and nitrogen dioxide concentration with urban population size by ANOVA test and linear regression, based on the selected literature from qualitative synthesis.

Hichem Omrani : Spatio-temporal Data on the air pollutant nitrogen dioxide derived from Sentinel satellite

Submissions are welcome for any topic of interest in quantitative and theoretical geography. In addition, 10 specifically organised sessions have been accepted, which we encourage you to consider while submitting your abstract. See the list of Special Sessions. You will notice that a new short video submission session, specifically dedicated to PhD students, is also launched to foster interactivity with younger scientists and promote creativity – See details at PhD180

Abstracts submission is via the EasyChair platform: https://easychair.org/conferences/?conf=ectqg2019 (you will need to use/create an account). Each abstract should have between 400 and 800 words. A speaker must be indicated among the listed authors and there is a limit on 2 proposals as a speaker.

In addition, we are particularly pleased to announce the following plenary talks:

Prof. Elsa Arcaute (UCL, United Kingdom)

Prof. Isabelle Thomas (UCLouvain, Belgium)

Prof. Luc Anselin (University of Chicago, USA)

Prof. Sara Fabrikant (University of Zurich, Switzerland)

More information about their talk will be communicated here. We are very grateful to the 4 of them for having accepted our invitation and supporting the ECTQG.

We are looking forward to seeing many of you in Luxembourg.
Should you have any question related to the submission, please do not hesitate to contact us by email at 2019@ectqg.eu
Happy submissions!
The ECTQG2019 organisers2019@ectqg.euhttp://www.ectqg.eu/ectqg-2019/

An exciting read at http://doi.org/10.1111/gean.12191 !

Alonso and the Scaling of Urban Profiles

Abstract: How urban characteristics change with total population, their scaling behavior, has become an important research field since one needs to better understand the challenges of urban densification. Yet urban scaling research is largely disconnected from intra‐urban structure, and this seriously limits its operationalization. In contrast, the monocentric model of Alonso provides a residential choice‐based theory to urban density profiles. However, dedicated comparative static analyses do not completely solve how the model scales with population. This article bridges this gap by simultaneously introducing power laws for land, income and transport cost in the Alonso model. We show that the equilibrium urban structure of this augmented model matches recent empirical findings about the scaling of European population density profiles and satisfactorily represents European cities. This result is however not compatible with the observed scaling power of housing land profiles, and challenges current empirical understanding of wage and transport cost elasticities with population. Our results call for revisiting theories about land development and housing processes as well as the empirics of agglomeration benefits and transport costs.

The call for Special Sessions is open until the 31st of January 2019. The call for papers will follow next from the 15th of February to the 15th of April.

Special Sessions will have between 4 and 6 registered participants. A Special Session must address a hot theoretical, methodological or thematic issues within the ECTQG scope.  If you would like to propose a Special Session, please send an email to 2019@ectqg.eu before the 31st of January, including the name(s) of the organiser(s), a short title for the session, a half-page description of its scope, intentions and plans to publish a special issue in a journal.

Each accepted Special Session will be listed and described on the colloquium website. At the time of abstract submissions, researchers will be able to attach their abstract to an accepted Special Session or will be allocated to general themes of the ECTQG. The organiser(s) of the Special Session will be in charge of abstracts selection after registration and a pre-screening from the Local Scientific Committee. For further details please consult the Colloquium website at www.ectqg.eu/ectqg-2019/

This edition of the ECTQG is jointly organised by the Institute of Geography and Spatial Planning of the University of Luxembourg and the Urban Development and Mobility Department of the Luxembourg Institute of Socio-Economic Research (LISER), grouped under the Quadtrees virtual lab.

The ECTQG is intended to cover a large set of topics where quantitative and theoretical geographers are involved these days in Europe and beyond. Following a long tradition, the topics will emerge directly from the network – that is from you! – by means of special hot topics sessions, as well as with standard sessions showing continuous progress in ideas and methods, including for example epistemology and theory, geographic information science, geoviz, spatial statistics, spatial interactions, networks, big geo-data, agent-based models, computer simulations, artificial life and intelligence, time geography, geo-history/archaeology, urban patterns and growth, fractals, scaling laws, economic geography, environmental and social sustainability, climate change, health geography, transport and land use…

Mondorf-les-Bains is a charming spa town, situated in the South-Eastern area of the Grand-Duchy of Luxembourg, next to the commune of Schengen. No better place for a European event!

Looking forward to seeing you

Regional science is an interdisciplinary field concerned with theory, method, and application of regional, urban and rural, geographic and spatial investigations and analyses.

In April 2018, Justin defended his thesis entitled “Urban Morphodynamics: Reconciling Location Theory and Complex Systems”. He was supervised by Professor Dominique Peeters and Professor Isabelle Thomas at the Université catholique de Louvain (BE).

The thesis is available here

Congratulations, Justin! Very happy to have you in Luxembourg!

Last year the prize was awarded to Dr Mirjam Schindler from the University of Luxembourg (now at Christchurch, NZ). Luxembourg is definitely the place to be for quantitative geographers and regional scientists!

Emerging urban form – Emerging pollution: Modelling endogenous health and environmental effects of traffic on residential choice

Air pollution bears severe health and environmental impacts and is of increasing concern to urban planners but densification strategies have ambiguous impacts. We analyse how households’ aversion to generating and being exposed to traffic pollution at the residential place and during their commute influences emerging urban structures and how these structures in turn affect pollution exposure and the residential choice of households. Resulting spatial patterns are difficult to predict because of this feedback and the spatial form of urbanisation and road networks. We address this complexity with a micro-economic agent-based residential choice model dynamically coupled with a cellular automata model for pollution dispersion and its perception in neighbourhoods. Our simulation experiments on a theoretical grid suggest that the spatial scale of this perception is important. We also find that if both health and environmental concerns are to be addressed, a combination of reducing commuting distances and preserving local green spaces is necessary. In particular, locally dispersed urban development and intra-urban green spaces next to busy roads can mitigate pollution exposure.

My first feeling was kind of uncomfortable on the first days with a kind of tabula rasa perspective to research. How can so many and so clever mathematicians and physicists (mostly) really get the grips on the most salient aspects of the research they address, given they seem to apply their skills to so many different topics from one day to the other? The common starting point seemingly being to have a big dataset. If geographers are seen as butterflies by economists (Duranton and Rodríguez-Pose) who think of themselves as lions, what would the latter think of complexity people?! Overall kind of frustration that complexity research seems to lack embedding of their research questions in existing literature. Setting this aspect aside (hoping that embedding is better in written pieces rather than talks) then the quality of the research is definitely overwhelming and reconciling: clarity and simplicity in formulation, clear cut interpretations. Delightful.

Beyond this general impression, the geography oriented research I listened to were definitely great. Not the least was the plenary by Céline Rozenblat from Lausanne on the second day, who entertained us visually and theoretically with a multi-scale network approach. An impressive talk showing a micro understanding of firms location and their role on the global organisation of cities. Very surprising to hear how much of intra-firm interactions are still actually happening within single cities despite the global connections. Also the way she used her empirical results across scales to move from resilience and adaptiveness to the idea of panarchy looked so evident from her work and promising. A specific workshop was then devoted to Open Mole and the computational exploration of models with geographical examples. The SpaceNet workshop also had a couple of talks related to cities (http://spacenet.sci-app.com/), including a very original talk I find by Enzo Nicosia (Queen Mary, London) on street network patterns, taking an areal approach rather than a street graph approach to let the shape of urban blocks emerge. A discovery was also (at least for me) the paper given by Ruiqi Li based on his recent Nature paper. Very dense and rich (too much maybe given again the connection to previous modelling work was rather scarce and details on formulations and parameters absent) presentation that resonates with some of our recent findings with Rémi Lemoy (soon in Env. & Plan. B) on density profiles and previous theoretical work with my S-GHOST fellows (Cavailhès, Frankhauser, Peeters, Thomas, Vuidel) on the emergence of sprawl patterns.

The paroxysm for an urban modeller was then the UrbanSys satellite. A total enjoyment and good occasion to know better the work of Diego Rybski (Potsdam Institute for Climate Impact Research) who shares very similar interests and ways to address intra-urban structures and their scaling.  The perspective offered by Dino Pedreschi (Pisa), although not geographical, finished to convince myself about the relevance of the complex systems research perspective. Not quite the exact quote, but in essence he said: “It is fake news that data driven approach will suffice, it needs theory!”. This is exactly what I wanted to hear! I then felt as a fish in water when presenting after a long long day our empirical research on the scaling of urban land and density profiles (with Rémi Lemoy) and of radial road networks (with Rémi and Estelle Mennicken) to which I adjoined some new set of theoretical simulations to better understand the origins of these structures and their scaling.

Do you see the cube or the hexagon? Both maybe? (and the Q of Quadtrees*, obviously!)

Sometimes we geographers have a flat x, y understanding of space. A useful simplification for sure…. sometimes. But space comes with many z dimensions: physical height, time, socio-economic, or environmental dimensions. A quadtree is a manner to compress a 2D (x,y) based information (z usually being a color code on a map) within a nested structure.

Measuring and modelling in geography is in all case a mental projection and a kind of scientific compression of what is happening. They are insufficient and do not pretend to bring up truth, but they are helpful simplifications and scientific constructs.

…all this wrapped up in a sleek logo!

 * Note that the name, Quadtrees, chosen for our virtual grouping of quantitative geographers in Lux, was suggested by Kate Jones within a brainstorming effort with Geoffrey Caruso who struggled to find a catchy and sensical name.