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1.
Several countries have made large investments in building historical Geographical Information Systems (GIS) databases containing census and other quantitative statistics over long periods of time. Making good use of these databases requires approaches that explore spatial and temporal change. The authors use a variety of visualization and spatial analysis techniques to explore population change in Ireland during and after the Great Famine of the late 1840s. Importantly, the techniques allow differences over space and time to be explored, thus stressing the diversity between places, rather than making all places appear the same, a common criticism of many statistical approaches. The authors demonstrate the potential of these techniques to explore geographical and temporal variations in large quantitative GIS datasets.  相似文献   

2.
Canonical correlation analysis (CCA) has the ability to deal with two sets of multivariate variables simultaneously and to produce both structural and spatial meanings. In view of the valuable insights to be gained, in this paper I examine the potential applications of CCA in regional science by describing its algorithm in a regional or spatial context. Next, I apply CCA to explore the mutually interdependent relationship between transport and development inChina's Zhujiang Delta. The results highlight the utility of CCA in revealing the structural and spatial patterns of two dominant and four subdominant transport-development relationships in this growing region of China.  相似文献   

3.
Environmentally Sensitive Areas (ESAs) designated under EC Structure Regulation 797/85 now cover 1.4 million ha of the Scottish countryside and are likely to make a substantial contribution to the regulation of landscape change. Visual changes to landscapes with (policy on) and without (policy off) the ESA programme in two Scottish ESA areas, Breadalbane and the Machair, are predicted through impact-assessment procedures and computer manipulation of photographic images. The methodological requirements for such predictions are outlined and substantial differences in landscape characteristics under policy on/off scenarios are revealed. Such approaches to landscape change are an essential foundation for the development of environmental cost-benefit analyses and will contribute to public consultation processes.  相似文献   

4.
Moran's Index for spatial autocorrelation and localized index for spatial association have been widely applied in many research fields as the first step to explore and assess the spatial dependency in a set of geographic events. This article presents extensions to the equations for calculating global and localized spatial autocorrelation so to include the temporal attribute values of the geographic events being analyzed. The extended equations were successfully implemented and tested with a real world data set. In addition, simulated data sets were used to reveal how the extended equations performed. Beyond the usefulness of the extended equations, we suggest that care be taken with regard to assessing spatiotemporal patterns under the normality and randomization assumptions as different outcomes from different assumptions would require different approaches for interpretation.  相似文献   

5.
Measuring the spatial correspondence among geographic features is an important component of many analyses such as those seeking to identify similar or dissimilar features, explore the extent to which change has taken place, and explain the processes influencing spatial change. In networked systems, the paths providing connectivity between pairs of nodes are often the geographic features among which spatial correspondence is to be assessed. That is, given a set of paths between a pair of nodes, the extent to which they share portions of the network and spatially deviate from one another can provide insight on the factors underlying the use of a system. While methods for measuring the spatial correspondence among specific types of network paths have been devised, this article proposes a methodology for measuring the spatial correspondence among the topology of network paths of any type, including those involving redundant use of network space. By basing comparisons upon the topologic relationships among the paths, the proposed approach better accounts for average spatial deviation as well as the asymmetric spatial relationship between pairs of paths, enabling greater stability and consistency in the analysis of their spatial characteristics. The developed methodology is applied to evaluate variability in spatial correspondence among a set of network paths to demonstrate its utility.  相似文献   

6.
以福建沿海地区为例,利用微观工业企业数据库,探究了重点开发区域工业空间演化、产业集疏差异及其形成机制。研究表明:福建沿海地区工业发展水平大幅提升且空间差距逐渐缩小,空间形态向成熟的产业带演进,产业空间分工表现出同质化特征;不同类型行业的空间集疏过程呈现出显著差异,其中资本密集型产业表现为持续扩散趋势;地形和生态可占性、资源环境承载力对产业空间形态具有基础性作用,地区经济技术是产业空间格局演化的重要驱动力,临港区位和交通条件改善不断促进产业发生空间集聚与扩散,区域发展战略以及产业政策为工业空间调整提供了具体方向。研究结论可为重点开发区域工业空间布局优化提供一定的借鉴。  相似文献   

7.
Model assessment is one of the most important aspects of statistical analysis. In geographical analysis, models represent spatial processes, where variability in mapped output results from uncertainty in parameter estimates. Slight spatial misalignments can cause inflated error scores when comparing maps of observed and predicted variables using traditional error metrics at the level of individual spatial units. We conceptualize spatial model assessment as a continuous value map comparison problem and employ methods from image analysis to score model outputs. The structural similarity index, a measure that attempts to replicate the human visual system using a local region approach, is used as an exploratory map comparison statistic. The measure is implemented within a Bayesian spatial modeling framework as a discrepancy measure in a posterior predictive check of model fit. Results are reported for simulation studies representing a variety of spatial processes in a spatial and space–time context. A case study of rainfall mapping in Sri Lanka demonstrates the proposed methodology applied to assessment of Bayesian kriging interpolations. Both simulation studies as well as the case study demonstrate that the approach reveals hidden spatial structure not uncovered by traditional methods. The spatially sensitive assessment methodology provides a diagnostic tool to support spatial modeling and analysis. La evaluación de modelos es uno de los aspectos más importantes de análisis estadístico. En el análisis geográfico, los modelos representan procesos espaciales en los que la variabilidad en los outputs es el resultado de la incertidumbre en los parámetros estimados. Leves desajustes espaciales pueden inflar los valores de error en la comparación entre los mapas de las observaciones y los mapas de las predicciones de las variables si es que se usan medidas tradicionales de medición de error al nivel de unidades espaciales individuales. Los autores conceptualizan la evaluación de modelos espaciales como un problema de comparación mapas de valor continuo y emplea métodos de análisis de imágenes para cuantificar los resultados del modelo. Se utiliza el índice de similitud estructural (SSIM), una medida que intenta replicar el sistema visual humano utilizando un enfoque de región local, como técnica de exploratoria comparación estadística de mapas. El índice es implementado dentro de un marco de modelización espacial bayesiano como medida de discrepancia en la comprobación posterior de predicción del desempeño del modelo. Los resultados se presentan para varios casos de simulación que representan una serie de procesos espaciales en un contexto espacio‐temporal y espacial. Un estudio de caso de mapeo de lluvias en Sri Lanka sirve como demostración de la metodología propuesta y su aplicación a la evaluación de las interpolaciones tipo krigeage (kriging) bayesianas. Tanto los estudios de simulación, así como el estudio de caso demuestran que el enfoque propuesto revela la estructura espacial oculta no evidenciada por métodos tradicionales. La metodología de evaluación espacialmente sensible que se presenta en este artículo proporciona una herramienta de diagnóstico para apoyar la elaboración de modelos y análisis espacial. 模型评估是统计分析中最为重要的内容之一。在地理分析中用模型表达空间过程,参数估计的不确定性会导致地图输出结果的可变性。当采用传统误差指标度量,在个体空间单位水平上进行观测和预测变量的地图比较时,微小的空间错位就可能导致误差的倍增。为此,本文通过将空间模型评估指标概念化为一个连续值图比较问题,并利用图像分析方法来评定模型输出。一种尝试以局域方法仿制人类视觉系统的度量指标——结构相似指数(SSIM),被用作为探索性地图的比较统计量。在贝叶斯空间模型框架下实现其量算,并将其作为一个偏差度量应用于模型拟合的后预测校验。仿真研究的结果显示出空间及时空环境下多类空间过程。以斯里兰卡降雨过程图为案例,展示了上述方法对贝叶斯克里格插值的准确性评估。仿真研究与实证结果均证明本文提出的方法可揭示以往传统方法掩盖的空间结构特征,空间敏感性评价为本研究的空间建模和分析提供了一个诊断工具。  相似文献   

8.
The purpose of this article is to examine how to measure the degree of similarity among various shapes, including for the first time those that are fragmented and perforated, by the overlap-based elongation index. It is argued that complete removal of the effects of position, size, and orientation on shape, which is essential for the calibration of shape similarity, can be achieved by a shape similarity index that varies continuously with changes in shape. After examining the characteristics of shape change, it is demonstrated that the elongation index is sensitive to changes in the shape of two spatial objects only when the centroids of the two objects are coincident. Two related rules of shape similarity are then presented. The applicability of the elongation index is evaluated by comparing several simple and complex shapes. The principal contribution of this article is that for the first time similarity among various shapes, fragmented or perforated, can be identified using the elongation index.  相似文献   

9.
Documentation of cutmarks is standard protocol in contemporary zooarchaeology. However, there is currently no consensus about how to best quantify them. This study examines differences in cutmark patterning using two approaches: 1) by means of an experiment, comparing a control cutmark pattern to ten simulated highly fragmented sets of front and rear limbs using %NISPcut as the quantitative unit, and 2) by quantifying an archaeological faunal assemblage using both the number of identifiable specimens (NISP) and the comprehensive minimum number of elements (cMNE). Results reveal significant differences in cutmark patterning between the control set and the simulated fragmented sets. Additionally, the ordinal-scale frequencies of cutmark anatomical portions (proximal, shaft, distal) are inconsistent and fluctuate across the simulated sets. Results of the zooarchaeological analysis show that differences between the two quantification methods are significant. In general, this study suggests that on heavily fragmented assemblages, interpretations of butchering behavior based on cutmark patterning are influenced by the chosen unit of quantification. Overall, using NISP as the quantitative unit provides inconsistent results, whereas, by alleviating the effects of high fragmentation, cMNE is more reliable.  相似文献   

10.
Economic utility indices provide a means of interpreting butchery and transport decisions reflected in the relative abundance of skeletal elements. Because of destructive taphonomic processes, interpreting skeletal element abundances in terms of carcass transport strategies requires that faunal analysts consider only those elements which accurately reflect their original abundances following human discard. In this study we use resampling techniques to examine the impact of sample size on correlations between high-survival skeletal element frequencies and economic utility in four simulated population assemblages reflecting distinct carcass transport strategies. Correlations alone do not accurately reflect the true relationship between bone abundance and economic utility as particular transport strategies have a tendency to generate high frequencies of Type II errors as sample size decreases. We show that the Shannon evenness index can be used as a quantitative means of distinguishing between bone assemblages characterized by subtle variations in skeletal element abundances. The evenness index can also be used to evaluate whether observed correlations reflect sampling error. Results from our simulations are applied to three published faunal assemblages to evaluate likely carcass transport strategies.  相似文献   

11.
This study uses worker‐level data on industry, occupation, and place of work to explore differences in the spatial properties of production, administrative, and R&D occupation groups within industries. To measure differences, we calculate location quotients at the local labor market level and the Duranton and Overman (2005) agglomeration index for each group. We find appreciable differences in the spatial distribution of occupation groups within most manufacturing industries, with R&D occupations consistently exhibiting the highest degree of spatial concentration. Our results are consistent with the core theoretical and empirical results in the agglomeration literature.  相似文献   

12.
Single and Multiscale Models of Process Spatial Heterogeneity   总被引:3,自引:0,他引:3       下载免费PDF全文
Recent work in local spatial modeling has affirmed and broadened interest in multivariate local spatial analysis. Two broad approaches have emerged: Geographically Weighted Regression (GWR) which follows a frequentist perspective and Bayesian Spatially Varying Coefficients models. Although several comparisons between the two approaches exist, recent developments, particularly in GWR, mean that these are incomplete and missing some important axes of comparison. Consequently, there is a need for a more thorough comparison of the two families of local estimators, including recent developments in multiscale variants and their relative performance under controlled conditions. We find that while both types of local models generally perform similarly on a series of criteria, some interesting and important differences exist.  相似文献   

13.
ABSTRACT. This paper develops a model of firm location choice based on managerial theory of discretionary behavior. Specifically, it is assumed that the management of the firm maximizes a utility function which incorporates profits and location-specific amenities. As the firm moves from one prospective location to another, it faces a profit-amenity constraint imposed by market conditions. The optimal location decision is derived by maximizing the utility function subject to this market-imposed constraint. After examining the properties of the optimal solution, the impact of various changes in product market structure (including changes from a contestible markets perspective) on the location decision is investigated. A major finding is that the impact of a change in market structure depends upon the nature of the structure change and upon the substitution and income effects induced by the structural change.  相似文献   

14.
The political economy of violence in Central America is widely perceived as having undergone a critical shift during the past two decades, often pithily summarized as a movement from ‘political’ to ‘social’ violence. Although such an analysis is plausible, it also offers a depoliticized vision of the contemporary Central American panorama of violence. Basing itself principally on the example of Nicaragua, the country in the region that is historically perhaps most paradigmatically associated with violence, this article offers an alternative interpretation of the changes that the regional landscape of violence has undergone. It suggests that these are better understood as a movement from ‘peasant wars of the twentieth century’ ( Wolf, 1969 ) to ‘urban wars of the twenty‐first century’ ( Beall, 2006 ), thereby highlighting how present‐day urban violence can in many ways be seen as representing a structural continuation of past political conflicts, albeit in new spatial contexts. At the same time, however, there are certain key differences between past and present violence, as a result of which contemporary conflict has intensified. This is most visible in relation to the changing forms of urban spatial organization in Central American cities, the heavy‐handed mano dura response to gangs by governments, and the dystopian evolutionary trajectory of gangs. Taken together, these processes point to a critical shift in the balance of power between rich and poor in the region, as the new ‘urban wars of the twenty‐first century’ are increasingly giving way to more circumscribed ‘slum wars’ that effectively signal the defeat of the poor.  相似文献   

15.
ABSTRACT

This paper establishes a multi theory framework to help explain factors and conditions promoting a political priority for policy change. The framework’s analytical utility is illustrated through its application to a case study of waste management in Australia. A lack of political momentum to prioritise regulatory interventions has contributed to uncoordinated responses by the Australian federal and state governments resulting in unsustainable approaches to waste management. Lessons are derived from the analysis that provide insights into the potential for establishing political priority for policy change from uncoordinated voluntary schemes to more coordinated regulatory approaches.  相似文献   

16.
Inference procedures for spatial autocorrelation statistics assume that the underlying configurations of spatial units are fixed. However, sometimes this assumption can be disadvantageous, for example, when analyzing social media posts or moving objects. This article examines for the case of point geometries how a change from fixed to random spatial indexes affects inferences about global Moran's I, a popular spatial autocorrelation measure. Homogeneous and inhomogeneous Matérn and Thomas cluster processes are studied and for each of these processes, 10,000 random point patterns are simulated for investigating three aspects that are key in an inferential context: the null distributions of I when the underlying geometries are varied; the effect of the latter on critical values used to reject null hypotheses; and how the presence of point processes affects the statistical power of Moran's I. The results show that point processes affect all three characteristics. Inferences about spatial structure in relevant application contexts may therefore be different from conventional inferences when this additional source of randomness is taken into account.  相似文献   

17.
This article discusses the utility of conceptualizing the transition to sustainable energy resources and technologies in terms of a significantly modified notion of strategic choice. This conceptualization combines recently popularized game-theoretic approaches with tools and concepts emerging from the application of nonlinear systems theory. These models, which involve systemic choices, explore a broader range of institutional dynamics than those commonly associated with prevailing notions of "public choice." They also explain a number of unique hybrid processes of public/private coordination and cooperation emerging in advanced industrial economies in Europe and Australasia.  相似文献   

18.
An error model for quantifying the magnitudes and variability of errors generated in the areas of polygons during spatial overlay of vector geographic information system layers is presented. Numerical simulation of polygon boundary displacements was used to propagate coordinate errors to spatial overlays. The model departs from most previous error models in that it incorporates spatial dependence of coordinate errors at the scale of the boundary segment. It can be readily adapted to match the scale of error–boundary interactions responsible for error generation on a given overlay. The area of error generated by overlay depends on the sinuosity of polygon boundaries, as well as the magnitude of the coordinate errors on the input layers. Asymmetry in boundary shape has relatively little effect on error generation. Overlay errors are affected by real differences in boundary positions on the input layers, as well as errors in the boundary positions. Real differences between input layers tend to compensate for much of the error generated by coordinate errors. Thus, the area of change measured on an overlay layer produced by the XOR overlay operation will be more accurate if the area of real change depicted on the overlay is large. The model presented here considers these interactions, making it especially useful for estimating errors studies of landscape change over time.  相似文献   

19.
Abstract

Functional magnetic resonance imaging (fMRI) has enabled us to look for the first time into the human brain in vivo, literally 'to watch it while it works'. This has resulted in exciting insights into the spatial and temporal changes underlying a broad range of brain functions, such as how we see, feel, move, understand each other, and lay down memories. The technique is safe, allowing repeated examinations to probe time dependent changes such as those involved in learning. Functional MRI is also improving our understanding of a variety of brain pathologies. Some, such as the addictive behaviours of gambling or drug abuse, are without structural brain changes. In other cases in which there are clear structural changes, fMRI has shown that functional changes occur in widely distributed regions of the normal appearing brain. Understanding these changes and the adaptive potential they confer promises to guide rational approaches to improving rehabilitation strategies. Here we briefly review these and related applications of fMRI for better understanding of the healthy and diseased brain.  相似文献   

20.
"The spread of HIV-1 in the United Kingdom is simulated by a model which integrates behavioural and epidemiological processes within a multi-regional population projection framework and represents the spatial heterogeneities in the distribution of HIV which have significant effects on transmission patterns. Analyses determine the significance of different parameters in contributing to prediction uncertainty and highlight the importance of behavioural change and international population movements."  相似文献   

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