Transformation of Istanbul from a monocentric to a polycentric city

This paper investigates the spatial transformation of Istanbul from a monocentric to a polycentric city following the growth of the city and the development of its communications systems. The population and employment of peripheral districts have been growing rapidly, while those of the core districts have decreased. In addition, other variables are utilized for the identification of polycentres such as tax revenues from commercial enterprises, weighted average trip length and volume of mail. The results of the study reveal that the old CBD of Istanbul is no longer a dominant employment centre. Instead, a new CBD is emerging at the intersection of the radial and the peripheral highways, and subcentres are developing in some of the first and second ring districts. A major contributing factor to Istanbul's polycentric development has been the transformation of its economy into one that requires large modem office space and facilities for private automobiles—both of which are difficult to provide within the old CBD. In addition, the construction of peripheral highways has contributed to a pattern of polycentric development. Moreover, there is a desperate need for planned development of these subcentres in order to prevent their current haphazard development and to give a character to the peripheral areas of Istanbul.     

空间联系视角的沈阳市多中心城市结构研究

以沈阳市为研究案例,借鉴国际著名团队POLYNET的研究经验并加以改良,进行了空间联系视角的多中心城市结构的实证分析。分别从人口密度分布、就业-居住空间联系网络与企业空间组织网络三个维度来识别沈阳市的人口中心、就业中心与产业中心,综合分析这些"中心"得出四点结论:①城市核心区就业与居住中心构成十字交叉的内循环结构;②浑南新区次中心特征颇具雏形;③外围人口中心、就业中心与产业中心错位发展;④沈阳市呈现不均衡的多中心结构特征。     

POPULATION DENSITY IN A CENTRAL‐PLACE SYSTEM

The existing empirical literature about polycentric population density has focused on the urban scale, and the alternative models proposed in that context have been justified using heuristic arguments. This paper describes how polycentric density distributions can, in general, be endowed with a theoretical framework which differs from the existing literature with respect to the treatment of centers: instead of assuming that they represent places of work, it assumes they are places that provide goods and services to households. This imposes a hierarchical structure on the model, which allows replacing the set of distances to all centers (typically used in the existing literature as the same explanans irrespectively of location) with a smaller set of distances that corresponds to the number of levels in the hierarchy and varies with location. The central‐place framework used also provides a direct link between a polycentric model and the Clark formula, in the sense that the latter can emerge through a smoothing procedure of the former. Finally, in the context of central places, the scope of related empirical investigations can be extended naturally from the urban to the regional scale. This is the scale of a simple test presented here, which has been specifically included to support the corresponding theoretical arguments about the structure of a polycentric density gradient. The paper concludes with some expected problems and advantages of applying these ideas to the urban scale.     

A Nonparametric Analysis of Employment Density in a Polycentric City

Nonparametric estimation procedures offer distinct advantages in modeling polycentric cities because they are flexible enough to account for functional form misspecification and incorrect subcenter sites. This paper presents locally weighted (LW) regression estimates of employment density in suburban Chicago. LW regression estimates are more accurate than OLS regression and capture the effects of missing variables. The results demonstrate that Chicago is indeed a polycentric city: although the traditional city center continues to affect employment density patterns in the suburbs, local peaks have developed around secondary employment centers.     

Polycentric Systems of Governance: A Theoretical Model for the Commons

Polycentricity is a fundamental concept in commons scholarship that connotes a complex form of governance with multiple centers of semiautonomous decision making. If the decision‐making centers take each other into account in competitive and cooperative relationships and have recourse to conflict resolution mechanisms, they may be regarded as a polycentric governance system. In the context of natural resource governance, commons scholars have ascribed a number of advantages to polycentric governance systems, most notably enhanced adaptive capacity, provision of good institutional fit for natural resource systems, and mitigation of risk on account of redundant governance actors and institutions. Despite the popularity of the concept, systematic development of polycentricity, including its posited advantages, is lacking in the commons literature. To build greater clarity and specificity around the concept, we develop a theoretical model of a polycentric governance system with a focus on the features necessary or conducive for achieving the functioning predicted by commons scholars. The model is comprised of attributes, which constitute the definitional elements, and enabling conditions, which specify additional institutional features for achieving functionality in the commons. The model we propose takes the concept a step further toward specificity without sacrificing the generality necessary for contextual application and further development.     

DELINEATING METROPOLITAN AREAS USING LAND PRICES*

ABSTRACT This paper proposes an approach to delineating metropolitan areas that is more general than the standard approaches in three respects: First, it uses the fraction of land prices attributable to economies of urban agglomeration instead of using commuting intensities as an indicator of economic integration between metropolitan centers and their hinterlands. Second, it identifies metropolitan centers endogenously instead of determining them exogenously. And third, it takes metropolitan subcenters explicitly into account. An empirical illustration is used to show that the approach tends to delineate fewer but larger metropolitan areas in densely populated regions, and smaller metropolitan areas in sparsely populated regions.     

THE EMERGENCE OF CENTRALITY IN A TRANSITION ECONOMY: COMPARING LAND MARKET DYNAMICS MEASURED UNDER MONOCENTRIC AND SEMIPARAMETRIC MODELS*

ABSTRACT This paper focuses on the emergence of Krakow's historic core as the city's economic center after Poland's economic reforms of 1989—reforms that introduced market forces into land markets. Using a semiparametric approach to identify pricing centers, an evolving and polycentric price surface is revealed. While the traditional city center emerges as the dominant node, the evolution of the price surface is far more complex than that found using alternative approaches. Accordingly, it yields superior explanatory power compared to simpler monocentric models and should caution against their use in metropolitan areas in transition or those that are polycentric.     

Some Extensions of Mills's Method for Urban Population Density Gradient Estimation

This paper extends Milk's method for estimating urban population density gradients to general noncircular and asymmetrical urban forms, using Gauss-Legendre quadrature embedded in a Newton-Raphson root finding algorithm. We also examine the sensitivity of the Mills method to measurement errors in the assumptions. Several issues arising from the comparison of analytical, Mills type estimation procedures with statistical procedures are explored, particularly in light of recent work that questions the negative exponential formulation of urban density gradients. We note in particular the influence of secondary population centers as a source of estimation bias.     

Apartment Rents: Another Challenge to the Monocentric Model

Extension of hedonic modeling strategy to the case of apartment rents in the Dallas region reveals the influence of a complex network of activity centers and highway axes. Nodes other than the CBD exert greater influence on rents than the CBD and amenity variables and externalities have both positive and negative effects. These findings demand reevaluation of the place normally assigned to higher-density rental housing in urban models.     

兰州城市建筑构成与空间分布研究

利用高精度卫星影象和大规模实地调查方法获取数据,采用GIS手段和数理统计方法,利用建筑占地面积和建筑面积两项指标,分别研究了兰州市及其各区、功能区、各组团圈层的现状建筑构成与空间分布特点和规律。研究结果表明了兰州市各圈层的各种建筑类型所占的地位及其差异、不同区不同圈层不同建筑类型建筑的年代构成和现代化趋势及其差异。     

City branding in polycentric urban regions: identification,profiling and transformation in the Randstad and Rhine-Ruhr

In polycentric urban regions several distinct cities, none of which is dominant, cooperate and compete with each other to attract inhabitants and firms. In such settings city branding strategies do not solely affect one city, but the entire region. We examined how city branding in the face of ecological modernization, that is, delivering higher added economic value, while lowering environmental impacts, is playing out in the Dutch Randstad and the German Rhine-Ruhr. Our findings show that regional identity formation occurs at the sub-polycentric urban region level, coinciding more with (historical) economic profiles than with planning imaginaries. The Dutch cities profile themselves more along the lines of ecological modernization than their German counterparts. Differences between subregions within each polycentric urban region are also noticeable, where more industrialized regions, such as the Ruhr or southern Randstad focus on ‘green’, ‘liveable’ and ‘knowledge-oriented’, while cities with stronger knowledge-intensive sectors portray themselves as ‘smart’ or ‘sustainable’. Cities generally substantiate their profiles through projects, but a significant gap persists between reality and aspirations for improved environmental conditions. This is especially true for the Dutch cities, where many claims, but little visible action can be observed.     

中国大城市旅游休闲业态的空间格局研究：西安案例

明确大城市旅游休闲业态的分布规律对于提高大城市旅游休闲要素配置效率及完善城市现代服务业体系具有重要意义。本文以机构兴趣点（POI）数据为基础,利用最邻近距离指数、核密度估计及地理探测器等空间分析方法,以西安市为案例探究中国大城市旅游休闲业态空间格局的规律性。结果表明,西安城市旅游休闲总体业态和细分业态均表现为在城市中心局部多核集聚,且业态密度由城市中心区向边缘区梯度递减的分布结构。而这一规律实则为消费市场、CBD区位、经济水平和路网密度等因素综合作用的结果。文章认为,为提高大城市旅游休闲产业要素配置的均衡性与高效性,城市管理者需兼顾城市中心及外围区域的统筹发展,并应在消费引导、资本投入、功能区建设和基础设施优化方面加大对外围区域的支持力度。     

Polycentric Transformation in Kenyan Water Governance: A Dynamic Analysis of Institutional and Social‐Ecological Change

Beginning in 2002, Kenyan water governance transitioned from a monocentric, top‐down system to one exhibiting traits of polycentricity. In this paper, we investigate the changes made to water policy following the 2002 reform, outcomes produced in a collection of community‐ and catchment‐level user groups in the Mount Kenya region, and the conformance of these changes and outcomes with principles of polycentricity. A new framework is used to capture the complex institutional arrangements and interactions existing before and after the polycentric transformation. Unlike many previous polycentricity studies, the present research focuses primarily on the outcomes of the polycentric shift and determines if these correspond to predictions from polycentricity theory. We utilize survey data collected in 2013 from water managers, as well as archival research to interrogate congruence with principles of polycentricity. This study contributes to the broader discussion on polycentricity in two fundamental ways: (i) It documents the functioning of a water management system following a top‐down imposed polycentric reform, and (ii) It empirically inspects whether these polycentric reforms have produced benefits predicted by polycentricity theorists, such as experimentation by local water users, increased collective action, and improved coordination between levels of management.     

浙江省区域创新中心空间格局及其驱动机制研究

区域创新中心建设对区域创新资源整合优化,发挥区域创新优势意义重大。研究运用最邻近距离、核密度估计、探索性空间分析等方法,分析浙江省区域创新中心空间分布、聚类特征及影响因素,得出以下结论:2013年浙江省区域创新中心空间分布整体呈现"周边少,中心多"的态势,空间点分布呈现凝聚特征,空间核分布存在明显不均衡现象;各县市区域创新中心空间分布同样呈现集聚特征,且存在明显的高值与低值集聚;区域创新中心的建设与发展需要市场各级主体的共同合作,同时还受到区域创新能力、经济发展水平、产业集群优势、政府政策因素以及空间邻近效应的影响。     

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.     

交通拥堵治理的空间与基础设施政策综述

交通拥堵是制约国内外城市可持续发展的瓶颈问题之一,给城市经济、社会与环境带来诸多负面影响.本文聚焦城市交通拥堵的结构性因素,系统归纳和综述了引导可持续出行行为的空间政策(如城市空间结构和土地利用政策)与基础设施供应侧政策(如道路和公共交通基础设施投资政策),及其在交通拥堵治理上的理论探讨、学术争论焦点、实证分析及当前亟...     

Prefiguring a future city: urban growth,spatial planning and the economic local context in Catalonia

This study undertook a quantitative analysis of town master plans to define future urban growth. Spatial direction and intensity of urban expansion were analysed in relation to local contexts using land zoning and a comprehensive database of socio-economic indicators at the municipal scale in Catalonia, Spain. Our results illustrate a progressive shift towards discontinuous settlements consolidating urban centres in most accessible rural areas. Contrary to what was hypothesized (and partly observed) in recent decades, settlement expansion will modestly contribute to a balanced urban spatial structure. Future urban development in Catalonia will not follow a polycentric model, fuelling instead the growth of medium and small urban centres. This process may consolidate the incipient divide in rural areas with high accessibility and a dynamic economic base with remote inland areas experiencing land abandonment and depopulation. The use of indicators derived from town master plans in the assessment of (scattered or polycentric) future urbanization in Europe is finally discussed.     

Building blocks of polycentric governance

Success or failure of a polycentric system is a function of complex political and social processes, such as coordination between actors and venues to solve specialized policy problems. Yet there is currently no accepted method for isolating distinct processes of coordination, nor to understand how their variance affects polycentric governance performance. We develop and test a building-blocks approach that uses different patterns or “motifs” for measuring and comparing coordination longitudinally on Australia's Great Barrier Reef. Our approach confirms that polycentric governance comprises an evolving substrate of interdependent venues and actors over time. However, while issue specialization and actor participation can be improved through the mobilization of venues, such a strategy can also fragment overall polycentric capacity to resolve conflict and adapt to new problems. A building-blocks approach advances understanding and practice of polycentric governance by enabling sharper diagnosis of internal dynamics in complex environmental governance systems.     

Commuting Distances and Gender: A Spatial Urban Model

In any urban center the commuting distances are a function of the spatial structure of the center and of the characteristics of the commuters. In this paper theoretical relationships between commuting distances and distances of residences to city centers are derived for monocentric and polycentric cities. These relationships are then linked to the sociological determinants of commuting distances. An econometric model encompassing both spatial structure variables and social variables is constructed and estimated using data for sixteen urban centers. Gender differences are focused upon. The expansion method is used.     

Why Are Cross‐Sectoral Forums Important to Actors? Forum Contributions to Cooperation,Learning, and Resource Distribution

Actors within an ecology of games in a polycentric governance system have to choose from a large number of forums they could participate in. This article analyzes why given types of forums are important to actors, as compared to other forums. It shows that functions of an ecology of games, such as cooperation, learning, and resource distribution, influence the importance that actors attribute to forums. The empirical analysis focuses on cross‐sectoral forums, a particular type of forum that is specialized in coordination among actors from different societal sectors, such as government, private interest, or science. Analysis of survey data from eight cross‐sectoral forums in Swiss habitat and land use governance and their 159 members shows that cross‐sectoral forums are comparatively important to actors that perceive their forum to contribute to learning and resource distribution.