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在地理学中,将科学方法主要用于解释和预测空间分布模式和空间相互作用的一种途径。直至20世纪中叶,地理学仍大多是描述性和分类性的研究,主要讨论地域之间差异或地域变异。不过,地理学从50年代起开始呈现变革和活跃之兆,其特征为地理学从描述转向分析,从分类转向建立理论,从地域变异研究转向空间分析或区位分析。  相似文献   

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Residual spatial autocorrelation is a situation frequently encountered in regression analysis of spatial data. The statistical problems arising due to this phenomenon are well‐understood. Original developments in the field of statistical analysis of spatial data were meant to detect spatial pattern, in order to assess whether corrective measures were required. An early development was the use of residual autocorrelation as an exploratory tool to improve regression analysis of spatial data. In this note, we propose the use of spatial filtering and exploratory data analysis as a way to identify omitted but potentially relevant independent variables. We use an example of blood donation patterns in Toronto, Canada, to demonstrate the proposed approach. In particular, we show how an initial filter used to rectify autocorrelation problems can be progressively replaced by substantive variables. In the present case, the variables so retrieved reveal the impact of urban form, travel habits, and demographic and socio‐economic attributes on donation rates. The approach is particularly appealing for model formulations that do not easily accommodate positive spatial autocorrelation, but should be of interest as well for the case of continuous variables in linear regression.  相似文献   

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Geographic information systems (GIS) are having tremendous impacts on many scientific and application domains. The traditional subfield of spatial analysis is witnessing a major resurgence and enhancement due to GIS and geographical information science (GISci), an interdisciplinary field focusing on the theory and methodology underlying GIS software. The interdisciplinary field of geographic information systems for transportation (GIS-T) has emerged to focus on the role of GIS in transportaton analysis and planning. This paper suggests the benefits of closer linkages between spatial analysis, GISci, and transportation through a focused review of spatial analytical issues and their potential contributions to GIS-T. Specifically, this paper reviews the following issues: (i) modifiable areal units; (ii) boundary problems and spatial sampling; (iii) spatial dependence and spatial heterogeneity; and (iv) alternative representations of geographic environments. The discussion highlights the general issues as well as identifies their specific relevance to GIS-T. In addition, this paper identifies some emerging tools from GISci that can address these spatial analytical issues in GIS-T.  相似文献   

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This paper illustrates the importance of spatial unit shape and orientation in spatial choice analysis. It also examines the implications of assuming spatial units to be dimensionless points in this context. Through theory and simulation experiments, it is shown how these aspects cannot be ignored and how the ordinary multinomial logit model applied at the spatially aggregate level is particularly vulnerable to such oversights. The aggregated spatial logit model in the end is recommended as a general formulation which addresses many of these fundamental issues of interest to geographers and regional scientists.  相似文献   

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Abstract

This paper studies the spatial dynamics of French agricultural cooperatives using the recently developed exploratory spatial data analysis tool. Analysis at the level of French districts in 1995 and 2005 shows strong evidence for global and local spatial autocorrelations in the geographical distribution of agricultural cooperatives. The presence of spatial disparities between French districts is confirmed by the detection of such specific spatial patterns as district clusters, a group of neighbouring districts with the same high or low level of agricultural cooperative activities. A typology of all the different Regions is developed to examine the specific spatial patterns of the agricultural cooperative activities. The results indicate that major organizational changes in cooperatives do not significantly modify the initial dynamics concerning the location of activities.  相似文献   

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The ability to detect anomalies such as spatial clustering in data sets plays an important role in spatial data analysis, leading to interest in test statistics identifying patterns exhibiting significant levels of clustering. Toward this end, Tango (1995) proposed a statistic (and its associated distribution under a null hypothesis of no clustering) assessing overall patterns of spatial clustering in a set of observed regional counts. Rogerson (1999) observed that Tango's index may be decomposed into the summation of two distinct statistics, the first mirroring standard tests of goodness-of-fit (GOF), and the second an index of spatial association (SA) similar to Moran's I . In this article, we investigate the effectiveness of Rogerson's expression of Tango's statistic in separating GOF from SA in data sets containing clusters. We simulate data under the null hypothesis of no clustering as well as two alternative hypotheses. The first alternative hypothesis induces a poor fit from the null hypothesis while maintaining independent observations and the second alternative hypothesis induces spatial dependence while maintaining fit. Using Rogerson's decomposition and leukemia incidence data from upstate New York, we show graphically that one is unable to statistically distinguish poor fit from autocorrelation.  相似文献   

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A test statistic for the detection of spatial clusters is developed by generalizing the common chi-square goodness-of-fit test. The paper includes a discussion of the relationship between the statistic and other associated statistics, and provides an analysis of both its null distribution and power. The paper concludes with the development of a local version of the statistic and an application to leukemia clustering in central New York.  相似文献   

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A test statistic for the detection of spatial clusters is developed by generalizing the common chi-square goodness-of-fit test. The paper includes a discussion of the relationship between the statistic and other associated statistics, and provides an analysis of both its null distribution and power. The paper concludes with the development of a local version of the statistic and an application to leukemia clustering in central New York.  相似文献   

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王培敏 《东南文化》2003,(11):61-62
从远古的端庄到明清的鲜活,玉鱼形饰件渐趋灵动,由此可窥中国美的历程之一斑。  相似文献   

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The Analysis of Spatial Association by Use of Distance Statistics   总被引:20,自引:0,他引:20  
Introduced in this paper is a family of statistics, G, that can be used as a measure of spatial association in a number of circumstances. The basic statistic is derived, its properties are identified, and its advantages explained. Several of the G statistics make it possible to evaluate the spatial association of a variable within a specified distance of a single point. A comparison is made between a general G statistic and Moran's I for similar hypothetical and empirical conditions. The empirical work includes studies of sudden infant death syndrome by county in North Carolina and dwelling unit prices in metropolitan San Diego by zip-code districts. Results indicate that G statistics should be used in conjunction with I in order to identify characteristics of patterns not revealed by the I statistic alone and, specifically, the Gi and Gi* statistics enable us to detect local “pockets” of dependence that may not show up when using global statistics.  相似文献   

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Wild canid populations exhibit different anatomical morphologies compared to domesticated dogs in North America. This is particularly important concerning archaeological sites, which may contain early domesticated species, for the proper identification of osteological remains. Previous studies have indicated domestic dogs exhibit a shorter rostrum accompanied by a crowded tooth row; however, none describe the overall complexity of these changes. Consequently, using a landmark‐based geometric morphometric analysis, cranial morphological characteristics were examined in North American wild canids: the gray wolf (Canis lupus), coyote (Canis latrans), red wolf (Canis rufus), and the domestic dog (Canis familiaris). The shape and size of the cranium in lateral and ventral views were compared between the three wild species to the group of domesticated dogs. Wild canids clustered separately from the domestic group in all statistical analyses. Results indicate an expansion of the orbital region, a compression of the rostrum, and an overall warping in the shape and orientation of the skull. In domestic species, there is also a downward shift in the frontal portion of the skull accompanied by the braincase assuming a more upward position. This technique successfully depicted how slight changes in isolated areas of the cranium can have an impact on the overall shape and morphology of the skull. We presume these changes in cranial anatomy reflect the recent selective pressures domestic dogs have undergone since diverging from their wild ancestors. Copyright © 2012 John Wiley & Sons, Ltd.  相似文献   

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Local forms of spatial analysis focus on exceptions to the general trends represented by more traditional global forms of spatial analysis. There is currently a rapid expansion in the development of such techniques but their history almost exactly parallels that of Geographical Analysis, with the first examples of local analysis appearing in the late 1960s. Indeed, Geographical Analysis has published many of the significant contributions in this field. This paper reviews the development of local forms of spatial analysis and assesses the current situation. Following a discussion on the nature and importance of local analysis, examples are given of local forms of point pattern analysis; local graphical approaches; local measures of spatial dependency; the spatial expansion method; adaptive filtering; multilevel modeling; geographically weighted regression; random coefficients models; autoregressive models; and local forms of spatial interaction models.  相似文献   

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杨建国 《世界历史》2020,(2):96-109,I0005,I0006
1977年的《巴拿马运河新条约》,是卡特政府在外交政策上的标志性成果之一。它的签署和通过,是卡特政府在复杂的国内外局势下实行双重政治博弈的结果。面对具有强烈民族主义倾向的巴拿马人民,卡特政府从国家长远利益出发,顺势而为,适度妥协;面对政府内部行政部门间的意见不一和顽固保守的国会势力,卡特政府在守住政策底线的前提下,通过巧妙施压和正面劝导,积极争取中间势力的理解和支持。这种内外博弈过程突出反映了在切实维护国家利益的重大外交决策问题上,美国现行宪政体制的功能和效用具有典型的两面性一方面,对内尽可能争取相关各方在重大外交政策上理解和支持的最大公约数,以有效增加美国对外政治斗争中获胜的筹码;另一方面,决策上的混乱拖沓增加了内耗,使得某些符合整体长远利益的重大外交决策不得不迁就于注重眼前、局部利益的国会系列修正案,导致重大外交政策的实施初衷与实际后果之间出现明显偏差。  相似文献   

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