The Hinterland's Stake in Metropolitan Growth: Evidence from Selected Southern Regions

In this article we extend the Carlino and Mills and Boarnet models of local development to test for the presence and direction of rural area linkages to urban areas in Functional Economic Areas (FEAs). In a sample of southern FEAs, we detect a mix of spillover and backwash effects from urban core and fringe areas to their rural hinterlands. Rural-area population and employment both grew faster than average between 1980 and 1990 if in an FEA with a pattern of urban decentralization.     

EMPIRICAL POLYCENTRICITY: THE COMPLEX RELATIONSHIP BETWEEN EMPLOYMENT CENTERS

Our paper empirically demonstrates that employment subcenters in large urban areas have important economic relationships with each other, and not solely with the central business district (CBD). Using data from Houston, Texas, we estimate polycentric density functions and show that “total” gradients differ from gradients using only own‐center coefficients. We model asymmetry by showing density is very different for centers with overlapping areas of influence. We conclude that subcenters have important yet heterogeneous linkages to each other in addition to the CBD, and that therefore the polycentric city is more complex than simply having additional centers mimicking the CBD.     

CHANGES IN THE NATURE OF URBAN SPATIAL STRUCTURE IN THE UNITED STATES, 1890–2000*

ABSTRACT This paper documents the long‐run trends in the average densities and density gradients of urban areas in the United States. The data show that between 1890 and 2000 the average densities of cities and metropolitan areas rose and fell but that the density gradients of urban areas generally declined monotonically over time. While it is beyond the scope of this paper to estimate the causes of these changes, this paper argues that a complete understanding of the changes in the nature of US urban spatial structures is likely to go beyond the standard explanations based on the monocentric city model such as decreases in transportation costs and increases in household incomes.     

A Surface-Based Approach to Measuring Spatial Segregation

Quantitative indices of residential segregation have been with us for half a century, but suffer significant limitations. While useful for comparison among regions, summary indices fail to reveal spatial aspects of segregation. Such measures generally consider only the population mix within zones, not between them. Zone boundaries are treated as impenetrable barriers to interaction between population subgroups, so that measurement of segregation is constrained by the zoning system, which bears no necessary relation to interaction among population subgroups. A segregation measurement approach less constrained by the chosen zoning system, which enables visualization of segregation levels at the local scale and accounts for the spatial dimension of segregation, is required. We propose a kernel density estimation approach to model spatial aspects of segregation. This provides an explicitly geographical framework for modeling and visualizing local spatial segregation. The density estimation approach lends itself to development of an index of spatial segregation with the advantage of functional compatibility with the most widely used index of segregation (the dissimilarity index D ). We provide a short review of the literature on measuring segregation, briefly describe the kernel density estimation method, and illustrate how the method can be used for measuring segregation. Examples using a simulated landscape and two empirical cases in Washington, DC and Philadelphia, PA are presented.     

人口的区位过程与城市的分形形态——关于城市生长的一个理论探讨

基于中心地假设,从城市人口分布的Sherratt模型和Naroll Bertalanffy的城乡人口异速生长关系出发导出关于人口分布空间动力学和城市扩展时空过程的数学模型,然后借助Batty等关于城市生长的DLA -DBM模拟结果证明人口的区位选择过程与城市的分形形态存在着内在关系。文章提出了关于区域人口运动和城市形态演化的三个基本原理:信息火商增原理、异速生长原理和Logistic发展原理。     

Alonso and the Scaling of Urban Profiles

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.     

西安市人口的分布变动研究

基于三次人口普查数据,对西安市80年代以来的人口分布变动进行了系统研究。结果表明:西安市在20世纪80年代便已形成"中心区人口减少、内圈和中圈人口快速增长、外圈人口低速增长"的区域差异格局,90年代这种区域差异格局更明显。通过人口分布模型的回归拟合,尝试性预测了西安市未来人口分布的趋势。结果显示:2010年西安市人口分布的峰值将出现在距市中心约2.5km的城墙与二环线之间。最后探讨了西安市人口分布变动的促进机制。     

Urban pattern and land cover variation in the greater Toronto area

Recent epistemological shifts in environmental geography have created a space to consider the interactions between ecological and urban systems more seriously. While openness to thinking about urban ecosystems has increased in recent years, there remain fundamental gaps in our knowledge. For example, recent research has examined the impact of urban–rural gradients on ecological conditions, but major voids exist regarding the relationship between urban development patterns and land cover heterogeneity, particularly for new forms of urbanization. This article attempts to address some of these gaps by examining the relationship between urban pattern and land cover in the greater Toronto area (GTA). In particular, measures of urban pattern that reflect aspects of development density, grain and function, as well as socio-economic characteristics, are systematically analyzed in relation to land cover heterogeneity. The regression analysis shows that multiple components of urban development pattern and socio-economic conditions are correlated with vegetated land covers, while urban density variables are not related. These results indicate more detailed representations of urban pattern should be incorporated into future human–environmental interaction studies in cities.     

基于POI大数据的资源型城市功能区识别方法与实证——以辽宁省本溪市为例

精准识别城市功能区对于优化协调城市人地系统，完善城市规划及促进城市可持续发展具有重要意义。选取公众认知度和地物一般面积对行业POI数据核密度进行加权，构建城市功能区定量识别方法，以本溪为例，输出城市功能区分布图并开展分析。结果表明：①考虑公众认识度与一般面积的核密度加权方法具有更高的实际性和准确性；②本溪市中心城区受地块大小、交通等因素影响，形成“多中心”组团、“单一-混合”功能区协同发展的空间格局。应进一步完善本溪新城区公共服务体系、优化旅游业产业链条，推进资源型城市转型进程。     

Cities in a pandemic: Evidence from China

This paper studies the impact of urban density, city government efficiency, and medical resources on COVID-19 infection and death outcomes in China. We adopt a simultaneous spatial dynamic panel data model to account for (i) the simultaneity of infection and death outcomes, (ii) the spatial pattern of the transmission, (iii) the intertemporal dynamics of the disease, and (iv) the unobserved city-specific and time-specific effects. We find that, while population density increases the level of infections, government efficiency significantly mitigates the negative impact of urban density. We also find that the availability of medical resources improves public health outcomes conditional on lagged infections. Moreover, there exists significant heterogeneity at different phases of the epidemiological cycle.     

The changing structure of a city: temporal changes in cubic spline urban density patterns

"Using the basic summary of urban structure given by the population density function, this paper estimates changes which have occurred in the structure of the Detroit [Michigan] metropolitan area during the past two decades. Both overall density changes and direction-specific changes are estimated using census data and the method of cubic spline regression. The results give more revealing insight into the structural changes which have occurred in the city than has been possible with traditional models of urban population density."     

From Simplicity to Complexity: The Changing Geography of Land Vulnerability to Degradation in Italy

Although territorial disparities in land quality are commonly observed in Mediterranean‐type ecosystems, how different geographical gradients impact the changing distribution of land vulnerable to degradation over time and space is poorly investigated in southern Europe. The present study assesses the spatial distribution of vulnerable land according to a composite index that describes the degree of land vulnerability to degradation in Italy along eight gradients during two time periods (1960–1990 and 1990–2010), representing distinct socio‐economic and environmental conditions. While the degree of land vulnerability increased at similar paces from 1960 to 1990 and from 1990 to 2010, the spatial distribution of vulnerable land changed considerably. From 1960 to 1990, the area of vulnerable lands increased in coastal areas, lowlands, and areas with moderately high population density, mainly owing to the increased climate aridity. By contrast, peri‐urban areas experienced, especially in northern Italy, the highest vulnerability from 1990 to 2010 owing to increased human pressure on land generating, e.g. land‐use changes. Results indicate that the importance of the gradients shaping the distribution of vulnerable land in Italy is reflected in the (changing) role of climate, vegetation cover, and human pressure as factors predisposing land to degradation. Finally, policy implications of the changing geography of vulnerable land in the Mediterranean region are discussed.     

基于Kernel密度解释的江苏省城市规模结构演化研究

城市规模结构研究可以反映城市在不同规模等级中的分布状况及城市人口集聚或分散程度,有助于认识城市体系发展所处的阶段以及该区域城市化进程的特征。研究运用Kernel城市空间密度分析方法,直观的反映了江苏省城市规模分布格局的连续变化。分别从城市体系的空间格局、城镇密集带的结构变化和长三角城市群城镇网络构建等视角对城市规模结构进行探讨,指出全省城市规模空间分布的Kernel密度在整体上具有西高东低、南密北疏的态势;城市体系的空间模式由最初的核心-边缘结构,逐渐向点-轴-面结构演化;南京都市圈的进一步延伸,将促进长三角多核心巨型城市网络向更大地域范围拓展。由此提出全省在不断优化城市体系的同时,需要更加注重大中城市及小城镇协调发展机制的建设,加强对苏中、苏北地区城市人口规模的扩张和城市规模布局的均衡,建立具备完整城市功能的网络城市发展模式,以更好的促进区域一体化发展。     

武汉都市发展区及主城区城镇常住人口空间分布格局——基于2010年第六次人口普查数据

武汉近期人地关系显著变化,相关分析时效性和精细度有限。基于六普数据,在都市发展区、主城区上叠加格网,运用Arc GIS、SPSS研究人口空间分布格局,发现都市发展区人口紧凑集中于三环内,两江交汇处密集成片,人口向主城区集聚态势仍显著,未出现明显郊区蔓延。揭示都市发展区人口分布呈显著集聚特征,存在"低密度人口冷点环带","冷点地区"与总规生态绿楔吻合。认为主城区人口密度分布呈整体多中心、局地单中心格局,4km范围内呈显著单中心,幂函数模型精确拟合。三环内形成1个人口主中心和4个次中心。9km范围内,主中心支配力强。9km外,主次中心差距缩小,次中心支配力彰显。推演出4km内的单核心模型表达式、9km及全域的多核心模型表达式。     

FLEXIBLE FORM METHODS FOR MEASURING RENT GRADIENTS*

ABSTRACT We develop and demonstrate an empirical methodology for measuring rent gradients in the presence of consumers that have varying tastes for distance to the city center. We derive easily calculated measures of rent gradients, own price elasticities, and income elasticities. We demonstrate the ease of calculation of these functions, even in the presence of consumers who have nonidentical preferences. We also demonstrate how to test for bias in rent gradient estimation that arises from assuming identical preference functions.     

Demand-Threshold Estimation for Business Activities in Rural Saskatchewan

Historically, a common technique used to assess a community's ability to support various business activities has been demand-threshold estimation. The concept of a demand threshold has been applied at the community level by estimating a relationship between community population and the number of establishments of a particular kind in the community. The approach taken in this research incorporates a spatial dimension (community urban proximity) in addition to community population to estimate demand thresholds. Using a count data technique, demand thresholds are estimated for 27 different business activities found in 584 rural Saskatchewan communities in 1990. Both population and urban proximity are found to be important explanatory variables.     

Cost Efficiency,Urban Patterns and Population Density When Providing Public Infrastructure: A Stochastic Frontier Approach

Relying on stochastic frontier analysis we propose a methodology to study the technological characteristics and cost efficiency levels related to the provision of public infrastructure for basic utilities. The methodology assumes a cost minimizing behaviour on the part of public officials when planning the construction of local infrastructure, which is represented by way of a flexible translog cost function. Introducing relevant definitions of scale economies, associated with larger numbers of inhabitants and dwellings, as well as economies of density, brought about by reductions in urban dispersion, we analytically determine the optimal population densities for which average cost is minimized. We illustrate our model with the water cycle sector, including water distribution, sewage collection and cleansing of wastewater, and considering data at the municipality level for the Spanish region of Castilla y León. The obtained results indicate potential cost savings in the form of decreasing average costs, as relevant scale and density economies are present, along with large inefficiency levels. Relevant policy guidelines favouring larger and denser urban sizes are drawn, as the observed cost excess is the result of a general suboptimal urban size in terms of population density, and the negative effects of dispersed settlement patterns.     

THE SIZE DISTRIBUTION OF URBAN AREAS: TESTING FOR THE APPROPRIATENESS OF THE PARETO DISTRIBUTION USING A GENERALIZED BOX-COX TRANSFORMATION FUNCTION*

ABSTRACT A widely held opinion among urban economists and geographers is that the Pareto distribution is an accurate representation of the urban size distribution of many countries around the world. This paper focuses attention on the appropriateness of the procedures used in the literature in arriving at this conclusion. We employed the generalized Box-Cox transformation function, which permits estimation of many functional forms for testing the Pareto distribution as special cases. The results obtained are illuminating albeit somewhat surprising. Except for one country the Pareto distribution is overwhelmingly rejected in favor of the general Box-Cox function. In more than 30 percent of all countries this form collapses to a reciprocal function. Moreover, as far as the overall goodness of fit is concerned, our results show that the General Box-Cox function is superior to the Pareto form.     

Population Distribution and Spatial Structure in Transitional Chinese Cities: A Study of Nanjing

Two geographers use population surface model techniques to analyze the distribution of population in Chinese cities. Focusing on Nanjing, they utilize detailed urban land use and building distribution data to develop a productive alternative method to reveal spatial variations in the distribution of inhabitants. The findings indicate that despite suburbanization, Nanjing remains a compact city with a population density that declines rapidly as distance from its central business district increases. Also, suburbanization has been limited to an inner area where population is densely distributed while commercial and office development is less prominent. Lastly, commercial activities influence the distribution of urban inhabitants and suburbanization more significantly than industrial development in suburbia. Journal of Economic Literature, Classification Numbers: O15, O18, R12, R14. 9 figures, 3 tables, 37 references.