The provision of urban green space and its accessibility: Spatial data effects in Brussels

in PLoS ONE (2018), 13(10), 0204684

Urban green space (UGS) has many environmental and social benefits. UGS provision and access are increasingly considered in urban policies and must rely on data and indicators that can capture variations ... [more ▼]

Urban green space (UGS) has many environmental and social benefits. UGS provision and access are increasingly considered in urban policies and must rely on data and indicators that can capture variations in the distribution of UGS within cities. There is no consensus about how UGS, and their provision and access, must be defined from different land use data types. Here we identify four spatial dimensions of UGS and critically examine how different data sources affect these dimensions and our understanding of their variation within a city region (Brussels). We compare UGS indicators measured from an imagery source (NDVI from Landsat), an official cadastre-based map, and the voluntary geographical information provided by OpenStreetMap (OSM). We compare aggregate values of provision and access to UGS as well as their spatial distribution along a centrality gradient and at neighbourhood scale. We find that there are strong differences in the value of indicators when using the different datasets, especially due to their ability to capture private and public green space. However we find that the interpretation of intra-urban spatial variations is not affected by changes in data source. Centrality in particular is a strong determinant of the relative values of UGS availability, fragmentation and accessibility, irrespective of datasets. [less ▲]

Assessing geographical effects in spatial diffusion processes: The case of euro coins

in Computers, Environment and Urban Systems (2017), 61

We examine how geographical structures impact diffusion processes within a regional system. From the example of euro coin diffusion across countries, we show how the relative position and population ... [more ▼]

We examine how geographical structures impact diffusion processes within a regional system. From the example of euro coin diffusion across countries, we show how the relative position and population endowment of regions impact our understanding of interregional mobility, beyond simple spatial interaction effects. The mix of coins of different origins is a complex but unique trace of the movement of individuals within a common currency area, potentially revealing a new facet of European integration. We simulate an individual-based dynamic model where agents move and exchange coins across regions. We analyse the convergence towards a homogeneous mix of coins through time for a series of different theoretical spatial systems. This sensitivity analysis demonstrates the impact of the regularity and aggregation levels, or centrality/periphery effects, on spatial diffusion dynamics. We then calibrate the model against empirical data for the regions of 5 European countries and provide estimates of mobility rates, distance decay and population attractiveness factors, affecting the diffusion of coins, hence international movements and European integration. [less ▲]

A perspective on urban economics and geographical agent-based models. (Keynote Speech)

Scientific Conference (2015, September)

In this presentation, we will argue that there are many benefits to further liaise urban economic models and geographically -aware agent-based simulation models for further understanding the structure and ... [more ▼]

In this presentation, we will argue that there are many benefits to further liaise urban economic models and geographically -aware agent-based simulation models for further understanding the structure and dynamics of cities, especially at the scale of city regions but also, eventually, for contributing micro understanding of changes in a system of cities. At first sight it appears that these two fields of urban research are very separated: urban economics relies mostly on mathematical proofs, a parsimonious set of interactions, static equilibria and a rather homogeneous space and set of agents; while geographical agent-based models emphasize the dynamics and complexity of cities, the heterogeneity of agents and space, and rely solely on computational methods. The presentation will showcase a series of theoretical and applied research to stress the idea that the two can fruitfully be combined and that results are then palatable to both urban economists and geographers and can therefore participate to consolidating a wider and formalised urban theory. The geographical turn towards agent-based approaches, compared to more aggregate models and behaviourally-blind geocomputational methods, is actually a chance for geographers to formalise market as well as non-market interactions in a manner that is consistent with urban economic theory and enhance the treatment of space in this theory. Relying on a formal description of agents utility permits to discuss normative instruments where environmental and welfare impacts can be traded-off by policy makers. Furthermore,, land or housing market outcomes of the models and the analytical efforts actually help to reduce parametric space and calibrate or validate models against independent data. [less ▲]

Greener and larger neighbourhoods make cities more sustainable! A 2D urban economics perspective

in Computers, Environment and Urban Systems (2015)

We analyse urban growth forms by means of a 2D microeconomic model where households value green space at neighbourhood scale. We analytically demonstrate that cities can grow more densely when households ... [more ▼]

We analyse urban growth forms by means of a 2D microeconomic model where households value green space at neighbourhood scale. We analytically demonstrate that cities can grow more densely when households have the possibility to enlarge the neighbourhood in which they value green space, thus emphasising the importance of neighbourhood planning in particular for facilitating short trips and views of green amenities. We also show by simulation that the size and form of the city, relative to the size and form of neighbourhoods, impact on the decision of households to leapfrog land or not, thus impacting on the emergence of scattered urbanisation patterns. We conclude that carefully addressing the spatial arrangement of green space and buildings and facilitating trips within neighbourhood units constitute an effective policy lever and an attractive way to deliver more sustainable cities. We further argue that our theoretical experiment with complementary analytical and computer-based simulation provides micro-economic reasoning to the main elements of the Garden City and neighbourhood unit planning concepts. [less ▲]

On the impacts of transport policies and urban form on traffic-induced air pollution (extended abstract)

in Hesse, Markus; Caruso, Geoffrey; Gerber, Philippe (Eds.) et al Proceedings of the BIVEC-GIBET Transport Research Days 2013 (2013)

Air pollution is a major concern in urban areas worldwide. It is not only a hazard to the environment but also on human health. Many argue that a compact city is the desirable urban form in the context of ... [more ▼]

Air pollution is a major concern in urban areas worldwide. It is not only a hazard to the environment but also on human health. Many argue that a compact city is the desirable urban form in the context of sustainability due to shorter travelling distances and reduced conversion of land. If considering not only the environmental pillar of sustainability in terms of total emissions but also the social one comprising human exposure and social well-being, the argumentation might change. The question we ask is whether selected common transport policies are efficient solutions to overcome the environmental and social challenge? In order to investigate this question, we developed a modelling system in order to test the impacts of different transport policies, either on the urban structure itself or on traffic flows and respectively on air quality. [less ▲]

Interactions between residential and daily mobility: Luxembourg case study in the MOEBIUS project (extended abstract)

in Hesse, Markus; Caruso, Geoffrey; Gerber, Philippe (Eds.) et al Proceedings of the BIVEC-GIBET Transport Research Days 2013 (2013)

We present the modelling strategy of the research project MOEBIUS, which aims at simulating future urbanisation and commuting mobility, including modal split, under various planning conditions. MOEBIUS is ... [more ▼]

We present the modelling strategy of the research project MOEBIUS, which aims at simulating future urbanisation and commuting mobility, including modal split, under various planning conditions. MOEBIUS is similar in its objectives to a Land Use and Transport Interaction (LUTI) model, although very modular in its implementation and with ability to deal with very fine spatial resolution inputs and outputs. We simulate (i) the future potential urbanisation in Luxembourg, (ii) the population and its spatial distribution, and (iii) the daily mobility (commuting pattern and travel mode choice) at a disaggregated level. [less ▲]

Friendly Batch Routing (FBR)

Software (2012)

The Friendly Batch Routing (FBR) application uses the Google Maps API to easily and simply gather route data for many origin-destination pairs. FBR is designed with usability in mind so that errors do not ... [more ▼]

The Friendly Batch Routing (FBR) application uses the Google Maps API to easily and simply gather route data for many origin-destination pairs. FBR is designed with usability in mind so that errors do not interrupt processing and skipped records can easily be resubmitted for processing. Additionally the FBR output can easily be imported into GIS packages. [less ▲]

Data mining in geographical contexts and texts

Presentation (2010)

An increasing number of institutions, acting at different scales and within different sectors, create in-house geographical information systems, e.g. for regional statistics, for land and transport ... [more ▼]

An increasing number of institutions, acting at different scales and within different sectors, create in-house geographical information systems, e.g. for regional statistics, for land and transport management, for local urban planning, etc. In addition, with the advent of new technologies, such as GPS's or web-mapping facilities, the use of such geographical data is being more and more popular and data is made more easily accessible (sometimes even contributed by the end-users). Geographers find themselves in rather data rich environments today (irrespective of homogeneity and quality). Also geographical objects require specific visualization and statistical methods. The application and adaptation of data mining approaches in geographical contexts is an increasingly important research topic. In this lecture we will start from theoretical considerations on data mining in geography, particularly emphasizing what is special with exploratory spatial data analysis. We will then refer to ongoing research related to geographical data mining undertaken at the University of Luxembourg in collaboration with colleagues from other institutions. A first example will refer to a large and homogeneous dataset of all dwellings within a Belgian province. Using graph theory and local spatial statistics, the data is used to identify and categorize urbanisation patterns across scales in an iterative way. A second example will depict an application of 'self-organizing maps' to understand patterns of 'territorial cohesion' in Europe using a rather small and lacunary dataset. The third example will be dedicated to a text-mining application to a rather large corpus of documents related to spatial development in Europe. This work funded under the ESPON (European Spatial Observatory Network) aims at producing a relevant thematic structure to the online regional statistics database of the ESPON network. [less ▲]

Geographical Modelling with Cellular-Automata

Presentation (2009)