Dimensions Of Urban Form Research Articles

Time, the other dimension of urban form: Measuring the relationship between urban density and accessibility to grocery shops in the 10-minute city

Compact settlements take advantage of economies of scale by sustaining a system of high-quality socio-economic services at close proximities. Urban density with a balanced mix of uses also benefits walking and cycling as mobility modes that provide sufficient access to urban amenities, especially when combined with effective public transport. Indeed, walking and cycling can decrease the use of cars for short-distance trips. From this perspective, urban density can help to reduce pollution, optimise energy consumption and decrease infrastructural expenditures while contributing to more attractive urban environments. These ideas have induced a new wave of time geography planning concepts, such as the ‘10-minute city’, to enhance urban sustainability. For these concepts to move beyond visionary narratives, they must be expressed in specific empirical frameworks. Thus, the current research focuses on accessibility to grocery shops, as an essential urban service, in the Stavanger metropolitan area (Norway) using 10 minutes isochrones for walking and cycling. The study integrates open data, GIS network analyses, statistical regressions and bivariate representations of the results. The research estimates the level of serviceability by quantifying the number of shops that are accessible for each location and interrelates this estimation with spatial and population densities. The paper also presents a method to detect spatial inequalities by visualising over/under-serviced areas. This visualisation can become a tool to support strategies to rebalance such imbalances. Moreover, this study offers a practical approach towards the ‘10-minute city’ concept, as it can be adjusted to different isochrones at different spatial scales. In general, this approach can serve both to analyse existing contexts and to model strategies to support sustainability policies, such as urban densification and the promotion of environmental-friendly transport.

Urban form and transportation energy consumption

Transportation energy is a significant portion of the energy consumption of the US economy. While various policies such as changing the fuel mix and alternative fuels are proposed to make the system more efficient, the efficacy of land use policies such as changing the urban form and densification have been subject to considerable debate. In this paper, I use a rich dataset compiled from different sources to test the effectiveness of urban form on energy consumption in the transportation sector. I proxy the consumption with retail sales from gas stations for most of the conterminous United States at a county level. Using demographic, economic and landscape characteristics, I tease out the effect of different dimensions of urban form on energy consumption. I find that compact and contiguous urban form is modestly associated with lower energy consumption and is more important than demographic concentration in explaining the variance.

Estimating the impacts of urban form on CO2 emission efficiency in the Pearl River Delta, China

The improvement of CO2 emission efficiency is of great significance to realizing energy-saving and emission reduction targets and achieving low-carbon development. While it is increasingly recognized that urban form could significantly influence the CO2 emissions of urban areas, few studies have been able to quantify the implications of urban form in relation to CO2 emission efficiency. The purpose of this paper is thus to contribute to existing literature by empirically quantifying how urban form influences CO2 emission efficiency. CO2 emission efficiency in this study is presented in terms of CO2 economic efficiency (CEE) and CO2 social efficiency (CSE). Firstly, we calculated the CEE and CSE of nine cities in the Pearl River Delta (Guangzhou, Shenzhen, Zhuhai, Foshan, Jiangmen, Zhaoqing, Huizhou, Dongguan, and Zhongshan) using locally important socioeconomic variables over the period 1990–2013. Then, seven landscape metrics were selected in order to quantify three dimensions of urban form (extension, irregularity, and compactness) using remote sensing data. Finally, panel data models were utilized to estimate the associations between urban form and CO2 emission efficiency. We identified a negative correlation between urban sprawl and CEE as well as CSE, a finding that indicates that urban growth decreases CO2 economic efficiency. Further, increasing irregularity in the form of cities was found to decrease both CEE and CSE—a larger degree of irregularity, in other words, results in lower CO2 emission efficiency. Conversely, urban compactness was identified as having a significant positive influence on both CEE and CSE, indicating that the compact development of cities can actually help to improve CO2 emission efficiency. The findings of this study hold important implications for building low-carbon cities in China.

On the discovery of urban typologies: data mining the many dimensions of urban form

The use of typomorphology as a means of understanding urban areas has a long tradition amongst academics but the reach of these methods into urban design practice has been limited. In this paper we present a method to support the description and prescription of urban form that is contextsensitive, multi-dimensional, systematic, exploratory, and quantitative, thus facilitating the application of urban typomorphology to planning practice. At the core of the proposed method is the k-means statistical clustering technique to produce objective classifications from the large complex data sets typical of urban environments. Block and street types were studied as a test case and a context-sensitive sample of types that correspond to two different neighbourhoods were identified. This method is suitable to support the identification, understanding and description of emerging urban forms that do not fall into standard classifications. The method can support larger urban form studies through consistent application of the procedures to different sites. The quantitative nature of its output lends itself to integration with other systematic procedures related to the research, analysis, planning and design of urban areas.

Realizing the box-counting method for calculating fractal dimension of urban form based on remote sensing image

In the research of fractal cities, the fractal dimension is very important. It is used to describe the fractal character of the city. The authors have designed two approaches to calculate the fractal dimension by the box-counting method through an example of Beijing, which are called the vector method and the grid method, respectively. The former calculates the fractal dimension through an intersecting analysis in ArcView; and the latter is carried out by programming in Matlab. They are compared from three aspects: the calculating process, the limits in use, and the results. As a result, the conclusion is made that there are merits and faults on both methods, and they should be chosen to use properly in practical situation.

The Evolution of Green Community Planning, Scholarship, and Practice: An Introduction to the Special Issue

Problem: How have the major visions of urban form evolved over the past century, and have they influenced practice and scholarship in green communities? Purpose: I examine how the major visionary ideas about urban form have influenced the evolution of green communities and provide a context for the forward-looking articles in this special issue. Methods: I appraise secondary sources of primary scholarship to describe and synthesize the main themes that influence green community thought and practice. Results and conclusions: Visionary ideals of green communities that embrace bioregionalism and other environmental dimensions that emerged in the early 20th century failed to take hold in contemporary planning practice. The ideals of green communities have become more salient in contemporary debates about community futures. Despite growing market demand for greener communities and emerging scientific consensus that green dimensions of urban form have a positive effect on sustainability, there is a widely shared dissatisfaction with the effectiveness of efforts to integrate the dimensions of green communities into the ways we build human settlements. Takeaway for practice: The forward-looking articles in this special issue recommend how planning and policy can be improved to better support the greening of our nation's communities. Authors recommend collaborative planning processes aimed at strengthening and mobilizing social networks to support green community initiatives, requirements and incentives that stimulate greener community and household behaviors, and new assessment tools for green building rating, and greenhouse gas inventory and analysis. Research support: None.

Quantifying Urban Form: Compactness versus 'Sprawl'

This paper develops a set of quantitative variables to characterise urban forms at the metropolitan level and, in particular, to distinguish compactness from 'sprawl'. It first reviews and analyses past research on the definitions of urban form, compactness and sprawl, and corresponding quantitative variables. Four quantitative variables are developed to measure four dimensions of urban form at the metropolitan level: metropolitan size, activity intensity, the degree that activities are evenly distributed, and the extent that high-density sub-areas are clustered. Through a series of simulation analyses, the global Moran coefficient, which characterises the fourth dimension, distinguishes compactness from sprawl. It is high, intermediate and close to zero for monocentric, polycentric and decentralised sprawling forms respectively. In addition, the more there is more local sprawl, composed of discontinuity and strip development, the lower is the Moran coefficient.

Analyzing Changes in Urban Form and Commuting Time*

Urban work trips have changed in important ways during the last decades. In Québec City, a medium-sized Canadian metropolitan area, commuting distances increased for both male and female workers between 1977 and 1996, while durations increased for male workers and decreased for female workers. This article seeks to identify spatial and social factors responsible for these changes. We develop a disaggregate model of trip duration estimated on the basis of large samples derived from travel surveys comparable through time. Using categorical variables to specify change, we are able to separate change effects from level effects attributable to various dimensions of urban form. Our analysis clearly indicates that, once travel mode and key social factors are controlled for, the shift from a monocentric to a dispersed city form is responsible, in the Québec metropolitan area, for increasing commuting time. This is contrary to findings in larger metropolitan areas, where, it has been argued, the suburbanization of jobs maintains stability in commuting duration.

Central dimensions in a sustainable urban development

AbstractSeveral dimensions of urban form and spatial urban development are discussed in the light of the main criteria of a sustainable development. If a sustainable development is to be achieved, it is necessary to avoid further urban sprawl. Low density, dispersed cities can hardly be energy efficient unless their inhabitants renounce the freedoms of choice characterizing today's cities with respect to job market opportunities, services and cultural events. However, a strategy for more compact cities should be cautious so that it does not decimate important green areas within the city, and localities of unfavourable microclimatic conditions should not be selected for residential construction. Planning for sustainability must be oriented towards long‐term and global goals, but should not rely solely on technical and instrumental rationality. A broad spectrum of planning strategies should be used, contingent on the concrete planning situation.