Correlating densities of centrality and activities in cities : the cases of Bologna (IT) and Barcelona (ES)

This paper examines the relationship between street centrality and densities of commercial and service activities in cities. The aim is to verify whether a correlation exists and whether some 'secondary' activities, i.e. those scarcely specialized oriented to the general public and ordinary daily life, are more linked to street centrality than others. The metropolitan area of Barcelona (Spain) is investigated, and results are compared with those found in a previous work on the city of Bologna (Italy). Street centrality is calibrated in a multiple centrality assessment (MCA) model composed of multiple measures such as closeness, betweenness and straightness. Kernel density estimation (KDE) is used to transform data sets of centrality and activities to one scale unit for correlation analysis between them. Results indicate that retail and service activities in both Bologna and Barcelona tend to concentrate in areas with better centralities, and that secondary activities exhibit a higher correlation

Local movement: agent-based models of pedestrian flows

Modelling movement within the built environment has hitherto been focused on rather coarse spatial scales where the emphasis has been upon simulating flows of traffic between origins and destinations. Models of pedestrian movement have been sporadic, based largely on finding statistical relationships between volumes and the accessibility of streets, with no sustained efforts at improving such theories. The development of object-orientated computing and agent-based models which have followed in this wake, promise to change this picture radically. It is now possible to develop models simulating the geometric motion of individual agents in small-scale environments using theories of traffic flow to underpin their logic. In this paper, we outline such a model which we adapt to simulate flows of pedestrians between fixed points of entry - gateways - into complex environments such as city centres, and points of attraction based on the location of retail and leisure facilities which represent the focus of such movements. The model simulates the movement of each individual in terms of five components; these are based on motion in the direction of the most attractive locations, forward movement, the avoidance of local geometric obstacles, thresholds which constrain congestion, and movement which is influenced by those already moving towards various locations. The model has elements which enable walkers to self-organise as well as learn from their geometric experiences so far. We first outline the structure of the model, present a computable form, and illustrate how it can be programmed as a variant of cellular automata. We illustrate it using three examples: its application to an idealised mall where we show how two key components - local navigation of obstacles and movement towards points of global locational attraction - can be parameterised, an application to the more complex town centre of Wolverhampton (in the UK West Midlands) where the paths of individual walkers are used to explore the veracity of the model, and finally it application to the Tate Gallery complex in central London where the focus is on calibrating the model by letting individual agents learn from their experience of walking within the environment

Comparative approaches for assessing access to alcohol outlets: exploring the utility of a gravity potential approach.

BackgroundA growing body of research recommends controlling alcohol availability to reduce harm. Various common approaches, however, provide dramatically different pictures of the physical availability of alcohol. This limits our understanding of the distribution of alcohol access, the causes and consequences of this distribution, and how best to reduce harm. The aim of this study is to introduce both a gravity potential measure of access to alcohol outlets, comparing its strengths and weaknesses to other popular approaches, and an empirically-derived taxonomy of neighborhoods based on the type of alcohol access they exhibit.MethodsWe obtained geospatial data on Seattle, including the location of 2402 alcohol outlets, United States Census Bureau estimates on 567 block groups, and a comprehensive street network. We used exploratory spatial data analysis and employed a measure of inter-rater agreement to capture differences in our taxonomy of alcohol availability measures.ResultsSignificant statistical and spatial variability exists between measures of alcohol access, and these differences have meaningful practical implications. In particular, standard measures of outlet density (e.g., spatial, per capita, roadway miles) can lead to biased estimates of physical availability that over-emphasize the influence of the control variables. Employing a gravity potential approach provides a more balanced, geographically-sensitive measure of access to alcohol outlets.ConclusionsAccurately measuring the physical availability of alcohol is critical for understanding the causes and consequences of its distribution and for developing effective evidence-based policy to manage the alcohol outlet licensing process. A gravity potential model provides a superior measure of alcohol access, and the alcohol access-based taxonomy a helpful evidence-based heuristic for scholars and local policymakers

Mobile Phone Data for Mapping Urban Dynamics

During the last few years, new tools for estimating people’s density in cities have emerged through mobile network data. As opposed to the more traditional methods of urban surveys, the use of aggregated and anonymous mobile phone network log files has shown promise for large-scale surveys with notably smaller efforts and costs. Moreover, a frequent data feed from the mobile network has been argued to demonstrate fine grain over-time variation in urban movements, lacking from the traditional prediction methods. Despite the positivist approach to the new methodology, additional evidence is needed to show how mobile network data correlate with the actual presence of people, and how they can be used to map different urban domains. We try to address this shortcoming presenting the results of a research carried out in Lombardy Region, using mobile phone data provided by Telecom Italia, as a promising approach to assist the traditional database and analysis of urban dynamics as new challenges for urban plannin

Patterns of population location in Auckland

This paper uses spatial statistical techniques to examine the economic determinants of residential location patterns in Auckland in 2006. The primary empirical focus of this paper is descriptive. We seek to establish the extent to which there are identifiable population subgroups that cluster together within the Auckland Urban Area, and further, to ascertain where these groups mainly live. It confirms previous findings of strong ethnic clustering and identifies clustering by qualification, income, and country of birth. It examines the interaction between incomes, land prices, and population density, and the relationship of land price with access to selected locational amenities.Residential location choice; local amenities; residential sorting

Methodology for the Assessment of Spatial Economic Impacts of Transport Projects and Policies

In this study we develop an integrated econometric and CGE modelling framework for transport projects and transport policies at the European level by integrating network, regional economic and macro-economic impacts. The paper presents the formal structure of the integrated econometric and CGE modelling framework, explains the calibration and applies it to the policy evaluation. The effects of infrastructure investments are modelled by simulating trade cost changes in a comparative static analysis, using estimates of trade cost changes due to new infrastructure links, obtained from a transport network model. By performing a systematic and quantitative analysis of the spatial, network and socio-economic impacts of transport investments and policy and carrying out scenario simulations we improve the under-standing of the impact of transportation policies on short- and long-term spatial development in the EU.Transport Policy, Impact analysis, Spatial CGE Model

Introduction

This collected volume gives a concise account of the most relevant scientific results of the COST Action IS1104 "The EU in the new complex geography of economic systems: models, tools and policy evaluation", a four-year project supported by COST (European Cooperation in Science and Technology). It is divided into three parts reflecting the different perspectives under which complex spatial economic systems have been studied: (i) the Macro perspective looks at the interactions among international or regional trading partners; (ii) the Meso perspective considers the functioning of (financial, labour) markets as social network structures; and, finally, (iii) the Micro perspective focuses on the strategic choices of single firms and households. This Volume points also at open issues to be addressed in future research