An Alternative Classification Scheme for Uncertain Attribute Mapping

The reality of uncertain data cannot be ignored. Anytime that spatial data are used to assist planning, decision making, or policy generation, it is likely that error or uncertainty in the data will propagate through processing protocols and analytic techniques, potentially leading to biased or incorrect decision making. The ability to directly account for uncertainty in spatial analysis efforts is critically important. This article focuses on addressing data uncertainty in one of the most important and widely used exploratory spatial data analysis (ESDA) techniques—choropleth mapping—and proposes an alternative map classification method for uncertain spatial data. The classification approach maximizes within-class homogeneity under data uncertainty while explicitly integrating spatial characteristics to reduce visual map complexity and to facilitate pattern perception. The method is demonstrated by mapping the 2009 to 2013 American Community Survey estimates of median household income in Salt Lake County, Utah, at the census tract level.     

And Did the Walls Come Tumbling Down? Ethnic Residential Segregation in Four U.S. Metropolitan Areas 1980-2000

The initial releases of data from the 2000 U.S. Census allow exploration of the extent of change, if any, in residential segregation in four major cities, where substantial population growth has continued to generate increased ethnic diversity. Using a recently established method of classifying residential areas according to their ethnic composition which facilitates comparative study over time and space, this paper examines segregation trends in Chicago, Los Angeles, New York, and Miami over the period 1980-2000 in the context of recent discussions of the nature of residential patterns there. It finds that though there has been some reduction in the extent of extreme segregation areas that are predominantly either White or African American with consequent greater ethnic mixing at the census tract level, nevertheless cores of extreme segregation remain, and these are being extended with greater segregation of the Hispanic population. Ethnic residential segregation in United States' metropolitan areas attracted much research throughout the 20th century, with each census providing new impetus for mapping and analysis. The 2000 census will be no exception, providing data with which the extent of change can be assessed after a further decade in which discrimination on the grounds of race and color was illegal. This paper provides an initial exploration for four metropolitan areas that have experienced substantial recent multi-ethnic in-migration. Using a method for classifying residential areas designed to facilitate comparative studies over space and time, it explores the extent of desegregation during the previous 20 years for each of the four main census ethnic groups.     

Residential Settlement Patterns among Immigrants in Atlanta Metropolitan Area,Georgia

This study investigates the diversity of immigrant populations and their spatial residential patterns at the census tract level within twenty‐nine counties of the Atlanta Metropolitan Statistical Area (MSA), using 2013 American Community Survey (ACS) five‐year estimates summary data from 2008–2012. Correlations coefficient analyses with local job opportunities, education level, and English proficiency and the presence of foreign‐born populations are also discussed. We find that immigrants have different patterns of settlement depending on their place of birth and region of origin. Local job opportunities, dominant language at home, and education levels also relate to the distribution of foreign‐born populations. Further research opportunities concerning differential settlement are discussed.     

NEW APPROACHES TO DELINEATING METROPOLITAN AND NONMETROPOLITAN SETTLEMENT: GEOGRAPHERS DRAWING THE LINE

The federal government's Office of Management and Budget, with staff support from the Census Bureau's Population Division, is responsible for maintaining the statistical standard that provides criteria used to define metropolitan settlement and that delineates individual metropolitan areas for use in federal statistics. Review of the current standard, which dates from 1990, is now under way in conjunction with the 2000 census. Reviews of the emergence of the metropolitan form of settlement in the United States and of previous geospatial units representing metropolitan settlement are provided. A framework of geospatial units to represent the various elements of settlement at the close of the 20th century, including metropolitan and nonmetropolitan forms, is offered. Three papers that provide new approaches to delineating metropolitan and nonmetropolitan settlement in the United States are introduced. [Keywords: metropolitan and nonmetropolitan settlement, geospatial units of analysis, federal government, statistics.]     

上海都市区边界划分——基于手机信令数据的探索

都市区是中心城市及其主要影响范围,在区域经济发展中有重要的引领作用。国外都市区范围根据中心城市与外围地区的通勤联系划分,本质上是与中心城市具有密切经济联系的统一劳动市场区。国内由于统计数据的缺乏,通过通勤联系划分都市区的相关研究难以开展,且划分结果在内涵上与国外都市区差异较大。移动电话是目前普及率最高的移动通讯终端设备,其包含的地理位置标签可反映用户的职住地信息。利用上海移动2014年上半年某两周2G手机信令数据,识别用户的居住地和工作地,参照国外标准,根据中心与外围地区的通勤联系划分上海市都市区。在通勤联系的基础上,尝试采用消费联系作为都市区划分的辅助标准,并对划分结果进行了调整。结果表明：① 基于通勤联系的上海都市区主要包括中心城周边地区、松江新城及外围大型工业区,基于消费联系调整的上海都市区包括中心城周边地区、松江、嘉定、青浦等新城及浦东惠南地区、长兴岛,整体上呈现东西略长、南北略窄的形态;② 通勤联系和消费联系可以相互结合划分中国的都市区边界,通勤联系作为主要指标,消费联系作为辅助指标;③ 上海与国外城市都市区差异较大,国外都市区范围扩展极广,上海都市区范围未超过行政边界,局限在在中心城周围相对较小的范围内。     

Research Note: Toward an Effective Subcounty Settlement Classification: Comparative Density Revisited

The federal Office of Management and Budget (OMB) defines metropolitan and micropolitan statistical areas (MSAs) for use by federal agencies in collecting and publishing statistics. In order to ensure their continued usefulness, OMB reviews and revises the standards for defining MSAs at least once every 10 years, typically prior to each decennial census. The most recent review was one of the most thorough and introduced some significant changes. Whereas the review produced a revised set of standards in December, 2000, OMB has encouraged continued research on a number of issues that remain open for discussion. These issues include: (1) the geographic building blocks used in defining statistical areas, (2) the creation of a settlement classification that encompasses all of the nation's territory, and (3) the categories of settlement (e.g., urban, suburban, rural) recognized within the classification. This note documents continuing research on how these issues might be addressed by using subcounty building blocks in a comparative population-density-based approach to classifying settlement.     

Whither the Jobs: Identifying Concentrations of Employment in Metropolitan Areas

Large concentrations of employment have developed outside traditional central business districts. Our research focuses on analyzing the changing distribution of employment in metropolitan areas by using tract-to-tract commuting data from Census 2000 to identify high-employment nodes within large metropolitan areas. We propose a new way to delineate clusters of contiguous high-employment tracts based on the job density in these areas. We then compare outlying employment clusters with traditional central business districts and contrast employment clusters of varying job densities. Our method has several advantages over existing methods of identifying employment clusters: it is conceptually simple, can use publicly available data, relies on a standardized geographic unit applicable across the entire United States, and offers the ability to examine data from multiple census years.     

COMPREHENDING COMPLEXITY

Since 1905 the Bureau of the Census has devised and applied concepts and criteria for delineating metropolitan areas and has published statistics describing them. The Office of Management and Budget (OMB) and its predecessor, the Bureau of the Budget, have defined metropolitan areas for use by federal agencies since introducing standard metropolitan areas (SMAs) for the 1950 census. In the late 20th century, new national United States settlement forms emerged, and distinctions between urban and rural areas or between metropolitan and nonmetropolitan areas lost both their theoretical and practical significance. A proposed system of national settlement areas, applied experimentally to eight diverse states, uses counties (towns and cities in New England) as basic statistical units, with each categorized by its population density as ranked within both its state and the nation. Relative population density alone is an adequate and appropriate surrogate for activity patterns and interaction among geographic units, approximating the patterns delineated by current practice, while blanketing the nation with non-overlapping statistical aggregates. [Key words: metropolitan area definition, urban population density, census geography.]     

ASIANS IN AMERICA'S SUBURBS: PATTERNS AND CONSEQUENCES OF SETTLEMENT*

ABSTRACT. In an effort to provide a more complex and multifaceted understanding of the process of spatial assimilation, this article explores alternative paths in understanding racial/ ethnic minority residential patterns. It scrutinizes patterns of contemporary Asian Indian and Chinese settlement in two metropolitan areas: Austin, Texas and Phoenix, Arizona. Though not particularly evolved in terms of their Asian immigrant settlement or dynamics, Austin and Phoenix represent the growing number of newly emergent Asian centers throughout the nation that have developed with the rapid rise of immigration from these two countries in the past several decades. The analysis utilizes records from the 2000 census to document and map Asian Indian and Chinese settlement within each metropolitan area and to investigate whether‐and to what degree‐each group is clustered or dispersed. The article then raises important questions about the consequences of concentration and dispersal for the incorporation of Asian Indian and Chinese residents.     

Spatial Mismatch and Employment in a Decade of Restructuring∗

Spatial barriers to employment limit women's job opportunities, but their effects differ among racial/ethnic minority groups. This study evaluates the degree of spatial mismatch for minority women and men by comparing the commuting times of African American, Latino, and white workers in the New York metropolitan region. Using Public Use Microdata for 1980 and 1990, we perform a partial decomposition analysis to assess the role of spatial mismatch in lengthening commuting times for minority workers. The results show that African American men and women living in the center of the region have poorer spatial access to employment than their white counterparts. In the suburbs, African American women and Latinas suffer no spatial mismatch; rather, their longer commuting times reflect greater reliance on mass transit. Comparison with 1980 findings reveals little change in spatial mismatch over time despite significant economic and social restructuring in the 1980s. Spatial barriers still limit employment prospects for the majority of minority women living at the core of the region.     

METROPOLITAN,URBAN, AND RURAL COMMUTING AREAS: TOWARD A BETTER DEPICTION OF THE UNITED STATES SETTLEMENT SYSTEM

Discontent with the current definition of metropolitan areas and the lack of differentiation within nonmetropolitan territory provided the incentive for the research presented here. Census tracts rather than counties were used as the building blocks for assignment of tracts, not just to metropolitan areas, but also to larger towns (10,000 to 49,999) and to smaller urban places (2,500 to 9,999). The analysis used 1990 census-defined urbanized areas and tract-to-tract commuter flows. Results include a modest shift of population from metropolitan to nonmetropolitan, as well as a significant reduction in the areal size of metropolitan areas, disaggregation of many areas, and frequent reconfiguration to a more realistic settlement form. [Key words: metropolitan, urban-rural, commuting.]     

Spatial Mismatch and Employment in a Decade of Restructuring*

Spatial barriers to employment limit women's job opportunities, but their effects differ among racial/ethnic minority groups. This study evaluates the degree of spatial mismatch for minority women and men by comparing the commuting times of African American, Latino, and white workers in the New York metropolitan region. Using Public Use Microdata for 1980 and 1990, we perform a partial decomposition analysis to assess the role of spatial mismatch in lengthening commuting times for minority workers. The results show that African American men and women living in the center of the region have poorer spatial access to employment than their white counterparts. In the suburbs, African American women and Latinas suffer no spatial mismatch; rather, their longer commuting times reflect greater reliance on mass transit. Comparison with 1980 findings reveals little change in spatial mismatch over time despite significant economic and social restructuring in the 1980s. Spatial barriers still limit employment prospects for the majority of minority women living at the core of the region.     

The spatial distribution of occupational prestige in metropolitan Tel Aviv

Summary Occupational prestige is the social value attributed to occupation, and in most instances indicates socio-economic status. It is obtained at the workplace and manifested in one's lifestyle in a specific place of residence, and its spatial distribution therefore follows the repetitive flow of commuters. The geography of such prestige has not previously been studied; this study uses the 1983 census to examine the spatial distribution of occupational prestige in metropolitan Tel Aviv, Israel. It was found that most workers use short, local commuting routes, which point to relatively closed secondary spatial labour markets. Common generalizations in research regarding commuting length and occupational status reflect the social composition of the entire workforce, with workers of higher occupational status tending towards longer commutes. Yet, this study shows that such commuting is also undertaken by workers of lower occupational status, while short commuting is also undertaken by workers of higher status. In addition, the results show that such generalizations are spatially differentiated.     

ETHNIC RESIDENTIAL CONCENTRATIONS IN UNITED STATES METROPOLITAN AREAS

ABSTRACT. Although residential concentrations of immigrant ethnic groups in cities were common a century ago, it is not clear to what extent members of more recently arrived groups live near each other. We attempt to determine how common such clustered settlement is today, using 2000 census data to measure concentrations of Asians, Hispanics, and their larger ethnic subgroups in fifteen large metropolitan areas. The percentage of an ethnic group that is residentially concentrated correlated significantly with the group's proportion in an area. With metropolitan areas weighted equally, 38 percent of Hispanics and 13 percent of Asians were concentrated. However, when we analyzed eight specific nationality groups, the residentially concentrated proportion ranged from 14 to 59 percent. Level of cultural assimilation appears to explain group differences in level of concentration. Although ethnic concentrations were more pronounced in the largest metropolitan areas, important concentrations were also found in many of the smaller areas in our study.     

RACIAL DIFFERENCES IN THE COMMUTING BEHAVIOR OF WOMEN IN BUFFALO, 1980-1990

Disagreement persists about whether or not African American workers in U.S. metropolitan areas are more distant from centers of employment opportunities than European American workers are. But few studies on employment accessibility focus on racial differences among women. Analyses of 1980 and 1990 census Public Use Microdata Samples for Erie County (Buffalo), New York show that, by 1990, African American and European American women who use private vehicles generally spend about the same time commuting. However in both years, work trips to destinations outside the central city penalize African American women relative to European American women. If employment opportunities, especially service jobs, continue to expand in suburban locations and not in central-city locations, the African American women who have to reverse commute (even when they use a car) are unlikely to enjoy the relative convenience of short commutes that characterize the journey-to-work behavior of European American women with suburban employment.     

北京市外来人口集聚型城中村流动人口职住分离研究

居住和就业是居民日常生活的主要内容,随着中国城市化进程加快,城市中低收入群体的职住分离现象正得到越来越多的关注。本文采用人口集聚指数、GIS空间分析及Logit回归分析等方法,利用北京市“六普”及实地调研数据,来获取外来人口集聚型城中村流动人口通勤及职住特征,并对影响因素进行分析。结果表明：①北京流动人口集中于城市拓展区,呈“环状圈层”分布特征。②近郊城中村流动人口通勤距离普遍较长,职住分离较明显,相应通勤时间也较长;远郊城中村流动人口通勤距离较短,以就地工作为主,由于远离城市核心区,公共服务设施的可达性较差。③家庭就业人数、未成年及老人数、住京时长、收入、受教育程度、行业、交通工具选择等对其通勤距离具有显著影响。上述结论可为研究城市弱势群体工作居住空间结构、制定城市规划等提供参考。     

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.     

Analyzing Changes in Urban Form and Commuting Time*

Abstract

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.     

Measuring rural settlement expansion in Uzbekistan using remote sensing to support spatial planning

Population growth demands sustainable spatial planning strategies for settlements in Uzbekistan, Central Asia, especially in rural areas that are inhabited by approximately 64 percent of the country's population. Where can settlements expand in rural Uzbekistan and does settlement growth affect valuable agricultural land? SPOT-5 data with a resolution of 2.5 m was utilized for mapping building layers and assessing settlement growth between 2006 and 2011 at the example of 53 communities located in the Khorezm province in North-West Uzbekistan. Object based image analysis was conducted, i.e. a multi-scale segmentation for the derivation of building contours, followed by a random forest (RF) classification of the object's spectral and spatial characteristics. A geographical information system (GIS) was used for identifying settlement densification and expansion processes, and for quantifying agricultural land parcels of different soil quality occupied during settlement growth.A calibration routine based on indices of segmentation quality enabled the selection of optimal segmentation parameters. After GIS-based refinements of the RF classification results, the overall accuracy (OA) of the building layers of both years exceeded 95%. The OA of the change map was 92.7%. The results revealed that the building area increased by 20%, whilst settlement expansion amounted to 10% in 2006–2011. Settlements widely expanded in accordance with the existing rules prohibiting the conversion of agricultural land to housing areas. Nevertheless, about 20% of the settlement growth occurred on agricultural production areas, also on those with highly productive soils. The results indicated both, the pressure on land resources for settlement growth and – in face of continuous population growth – an increasing demand for comprehensive spatial planning in rural Uzbekistan. The elaborated methodological approach can be extrapolated to regions throughout Central Asia with similar environmental conditions.     

Human-Environment Patterns of Metropolitan Spatial Restructuring:Atlanta,Georgia and Shanghai,PRC,1950-2000

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