Environment and Planning B: Urban Analytics and City Science

It is not yet completely understood how on-site costs for infrastructures in residential developments vary with lot size and how developers respond to this relationship. Utilizing data from public records of costs for constructing twenty-eight subdivisions in South Kingstown, RI, this paper examines how developers' on-site costs per lot for sewer and water services and roads vary with lot size. Contrary to previous results, this study finds that these on-site costs per lot can decrease as lot sizes increase. The literature on decision making by developers suggests that this cost relationship can be advantageous to small satisficing developers, leading them to prefer larger lots. To encourage small developers to build denser developments on smaller lots, local governments should consider incurring the upfront costs of certain on-site infrastructures and be reimbursed by developers when the lots are sold.

In the United Kingdom planning favours a more compact, high-density, and mixed-use urban form. Many of the claims made for such compact forms in terms of the sustainability benefits are contested, and few have been rigorously researched. Drawing upon policy and academic literature we identify two key dimensions of social sustainability: social equity and sustainability of community. Using data from the Survey of English Housing this paper analyses the relationship between key aspects of urban form, density, and housing type, and selected social sustainability outcomes. Simpler analyses suggest strong relationships between urban form and a range of outcomes, although in opposite directions for the equity and community dimensions. However, the impact of urban form on these outcomes is substantially modified once we control for exogenous and intervening demographic and socioeconomic factors. In addition, outcome patterns relating to access to services and facilities favour denser urban forms at the same time as outcomes relating to sustainability of community remain adverse in denser areas. This suggests trade-offs within the social dimensions of sustainability, as well as between the social, environmental, and economic dimensions.

Desertification in Spain is a largely society-driven process, which can be managed effectively only through an understanding of environmental, sociocultural, and economic driving forces. This calls for a more active role of decision makers and other stakeholders. We present two promising approaches—participatory stakeholder workshops and a spatial policy support system (PoSS)—to develop future scenarios of land-use change for a watershed in Spain. We furthermore discuss the efforts involved and the added values of combining both methods. Based on two local workshops, three scenarios were constructed, which were subsequently formalised, parameterised, and quantified. We conclude that there are large advantages of linking narrative storylines and a spatial PoSS. Storylines ensure an active participation of a large range of stakeholders, additionally offering the possibility to develop highly integrated scenarios. The PoSS provides a spatially detailed and quantitative output, that can also be used to check the internal consistency of the qualitative scenarios. Linking stories and models can thus open the way for more successful management strategies to combat land degradation.

Generated traffic has received considerable worldwide attention for its ability to congest newly built roads or return improved roads to their original congested states. By investigating impacts resulting from two contentious highway projects in the Hamilton Census Metropolitan Area, Canada, we address two outstanding issues relating to the study of generated traffic. First, we find that the type of measure used to quantify the phenomenon can impact significantly evidence of its existence. Second, we decompose successfully generated traffic into its constituent parts, namely, induced travel and diverted travel. We also identify the source of each component. Next, we document statistically significant changes in the spatial distribution of traffic flows in the vicinities of the new expressways and throughout the entire network. Finally, our analysis of traffic congestion and vehicular emissions of three pollutants (carbon monoxide, hydrocarbons, and nitrogen oxides) suggests that while the new expressways may prove beneficial to the system as a whole, this is not the case for their immediate environs.

For more than four decades, two address-matching methods, the street-based address geocoding method and address-point-matching method, have been used to identify geographical coordinates from postal addresses. However, street-based address geocoding methods developed for the US addressing system are not universally applicable in developing a single-portal geocoding middleware for worldwide Internet-based geographic information systems applications. Problems also exist with address-point matching especially in its capability to identify features and incorporate 3D locational data from 3D addresses for analysis of large public buildings, shopping centers or metro-subways, that exist in urban environments. To alleviate these problems, this paper details two alternative address-matching methods, an area-based address geocoding method and a 3D address geocoding method. The area-based address geocoding method is a 2D positioning method based on a 2D area-based address-matching technique. The 3D address geocoding method is based on a universally applicable 3D address-geocoding technique. To elaborate, this paper introduces (1) a BlockObject model and designs reference databases for an area-based address system, (2) a 3D indoor network model representing the internal structures of urban environment, and (3) a 3D address geocoding algorithm based on a 3D indoor geocoding method. To illustrate the benefits of the 3D address-positioning method, this paper implements 3D indoor navigation to define optimal routes within a single building.

This paper explores the potential of geographic information systems (GIS) in the study of urban historic cartography. The first part of the paper focuses on three European schools of urban morphology, that have been using cartographic analysis in the study of the city, since the first half of the 20th century. Built on this theoretical context, the second part describes the use of GIS in redrawing historic maps of Lisbon and Oporto. A discussion of the fundamental contribution of this method is then presented. GIS encourages and enables rigorous representation of the spatial characteristics of urban phenomena. Furthermore, the application of this method provides the following five main outputs: a dynamic framework to represent the evolution of the urban form, continuously open to the addition of, and articulation with, other morphological and planning data and information; the overall and simultaneous vision of the urban-form evolution of a particular city in a long time period; the rigorous identification and characterization of urban-expansion areas; the opportunity to systematically analyse unexplored urban-development processes; and, finally, the possibility to typify the urban fabric, taking advantage of a rigorous and versatile cartographic tool.

Microscopic observations were performed in order to examine bidirectional collision-avoidance behaviour of pedestrians on stairs. Results suggest that characteristics of collision avoidance on stairs are different from those in a busy flat space. On stairs, pedestrians tended to detour at the beginning of a flight to avoid collision with another pedestrian already on the stairs. The authors call this lane collision avoidance. The side preference of pedestrians on stairs and the handedness of two-lane flows were explored. On dextral staircases, most pedestrians chose the right-hand side for collision avoidance, whereas in sinistral staircases, pedestrians did not necessarily choose the right-hand side. Investigation of the relative position of one pedestrian to another leading pedestrian showed that following pedestrians tended to shift laterally in relation to a leading pedestrian when the ‘front-back’ interpersonal distance between them was small. The obtained knowledge is useful for the development of pedestrian simulations.

This paper investigates the effects of city size, shape, and form, and neighborhood size and shape in agent-based models of residential segregation. We find that, in many key respects, model-generated segregation outcomes are not influenced in important ways by variation in these factors. For example, the expression of segregation based on agent preferences for coethnic contact in agent-based models does not vary with city size, city shape, city form, or the shape of neighborhoods involved in agent vision, or the use of distance-decay functions for evaluating neighbors. These findings indicate that results obtained from model-based segregation studies are likely to be robust relative to choices regarding these aspects of model specification. We do find important effects of the size or scale of neighborhoods involved in agent vision: model-generated segregation outcomes vary in complex ways with agent vision. Significantly, however, the effect of neighborhood size or scale does not appear to vary in important ways with neighborhood shape. Thus, what is important is the scale of agent vision—that is, the number of neighbors they ‘see’—not the particular spatial arrangement of those neighbors. With the exception of the effect of the spatial scale of agent vision, our results suggest that researchers can generally presume that their findings regarding how model-generated segregation outcomes vary with substantive factors, such as agent preferences for coethnic contact or the ethnic demography of the city, are not contingent on choices regarding model implementation of city size, city shape, city form, and neighborhood shape. These findings are welcome because they suggest that simulation studies can devote less attention to technical specification choices and more attention to assessing substantive questions regarding the effects of social dynamics and sociodemographic distributions in the context of model systems.

There have been few attempts to map or monitor urban environmental quality (UEQ) at a detailed level, or as a holistic concept comprising multiple parameters. This study examines methods and scales for integrating six parameters of UEQ, which are measured in different units and operate at different scales, into a single index for mapping UEQ differences over an urban area, the Kowloon Peninsula, Hong Kong. The parameters comprise vegetation density, heat island intensity, aerosol optical depth, building density, building height, and noise. Two approaches for spatial data integration—principal component analysis (PCA) and GIS overlay—were examined for integrating the datasets at three different levels of detail, namely electoral-district level, and raster datasets at 4 m and 64 m resolution. At all levels of detail mapped, the GIS overlay method was found to be more representative of UEQ as perceived in the field than when parameters were combined by PCA. High (4 m) spatial resolution was more representative than either 64 m resolution or UEQ mapped within electoral districts. The combined parameters vegetation density, building density, and building height gave a better index of UEQ than all six parameters combined, or any individual parameter or combination, and the best single indicator of UEQ was found to be vegetation density. Since vegetation density, building density, and building height are now relatively easy to obtain at detailed level from GIS databases or high-resolution satellite images, planning and environmental authorities may use the derived UEQ index as an objective measure of environmental quality over a whole city, for comparisons between places and cities and for monitoring changes over time.