共查询到20条相似文献，搜索用时 27 毫秒
1.
C.WEIHS Mathematical Applications Information Services R-.Z. CIBA-GEIGY Ltd. CH- Basel Switzerland 《地理学报(英文版)》1993,(5)
Exploratory data analysis(EDA)is a toolbox of data manipulation methods for looking at data to seewhat they seem to say,i.e.one tries to let the data speak for themselves.In this way there is hope thatthe data will lead to indications about'models'of relationships not expected a priori.In this respect EDAis a pre-step to confirmatory data analysis which delivers measures of how adequate a model is.In thistutorial the focus is on multivariate exploratory data analysis for quantitative data using linear methodsfor dimension reduction and prediction.Purely graphical multivariate tools such as 3D rotation andscatterplot matrices are discussed after having introduced the univariate and bivariate tools on which theyare based.The main tasks of multivariate exploratory data analysis are identified as'search for structure'by dimension reduction and'model selection'by comparing predictive power.Resampling is used tosupport validity,and variables selection to improve interpretability. 相似文献
2.
探索性空间分析及其与GIS集成模式探讨 总被引：2，自引：1，他引：2
探索性空间分析基于让数据说话的理念,可以避免野值或非典型观测值的误导。在对探索性空间分析的基本原理和概念界定的基础上,探讨交互式和动态空间数据分析、地学可视化及可视化空间分布、确认性空间分析、空间数据挖掘等探索性空间分析的主要技术。由于统计分析软件和GIS的数据格式差异很大,直接将二者简单集成存在一定困难,因此切实可行的集成方式是采用对象连接和嵌入(OLE)技术,分别调用统计分析软件的探索性分析功能(或者函数)以及GIS的地图显示和空间分析功能,并进行必要开发,实现二者的集成。最后对探索性空间分析的发展方向进行展望。 相似文献
3.
MARK GAHEGAN 《International journal of geographical information science》2013,27(4):289-309
This paper outlines four specific problems that appear to represent considerable obstacles to the development of visualisation strategies for use within the domain of geography and the Earth sciences. These are: (1) the speed of graphical rendering, (2) the management of perceptual anomalies due to visual combination effects, (3) the vast range of potential approaches and mappings (the complexity of the visual assignment process), and (4) the orientation of the user into an artificial or virtual reality. Each problem is discussed in terms of the visualisation of geographical data for the purpose of exploratory visual analysis. The specific underlying research issues and questions are described, with particular emphasis to how these relate to the geographical domain. Where possible, some potential solutions are suggested. Specific examples of geographical data visualisation are given to substantiate the arguments presented. The discussion highlights the need for further research in a number of key areas, and stresses the weaknesses of current visualisation theory and technology when applied to non-trivial geographical datasets. 相似文献
4.
Alan T. Murray Tung-Kai Shyy 《International journal of geographical information science》2013,27(7):649-667
This paper develops an interactive approach for exploratory spatial data analysis. Measures of attribute similarity and spatial proximity are combined in a clustering model to support the identification of patterns in spatial information. Relationships between the developed clustering approach, spatial data mining and choropleth display are discussed. Analysis of property crime rates in Brisbane, Australia is presented. A surprising finding in this research is that there are substantial inconsistencies in standard choropleth display options found in two widely used commercial geographical information systems, both in terms of definition and performance. The comparative results demonstrate the usefulness and appeal of the developed approach in a geographical information system environment for exploratory spatial data analysis. 相似文献
5.
Richard Arthur Reyment Isao Motoyama Miyuki Ota Yuichiro Tanaka 《Natural Resources Research》2008,17(3):187-195
A statistical analysis of two consecutive sequences of observations on radiolarian abundances in the western North Pacific,
by methods appropriate to data on the simplex (i.e., compositional data), show that although the overall graphical presentations
of the frequencies appear similar, there are substantial differences in the earlier part of each of the series. The results
of the multivariate analyses are used for identifying those species that contribute most to the analysis. A brief guide to
the mathematical properties of compositional data is given. 相似文献
6.
Jing Tian Mengting Yu Yingzhe Lei 《International journal of geographical information science》2019,33(3):537-566
The spatial patterns of road networks reflect the morphological and structural characteristics of cities. Previous studies have focused mainly on seeking universal laws in road networks rather than explaining their differences. A new approach for road network pattern analysis is proposed that has been inspired by landscape metric analysis. The utility of this approach is illustrated through (but is not limited to) the extraction of the main factors in network landscapes, or network-scapes for short. Twenty-four metrics were calculated for network-scapes of 100 cities worldwide, before an exploratory analysis is performed to detect the main factors. Four main factors were revealed and may be regarded as the characteristic indicators of road networks, which were identified to be evenness, richness-density, shape irregularity, and size and shape variation. The meanings of these factors are explained, and their spatial distributions are illustrated. Compared to existing road network analytics, these factors depict better the characteristic differences of road networks. The proposed approach provides a new framework for road network pattern analysis from a cellular perspective. 相似文献
7.
A pedogeochemical exploratory survey of gold deposits was carried out in the region of São Sepé (southernmost Brazil). The region comprises a predominantly metamorphosed belt of volcanoclastics, sediments, serpentinites, basalts, gabbros, chert, tuffs, and banded iron formation of the Proterozoic age. The anomalies were identified first by stream sediment heavy mineral survey at the regional scale of exploration. Once spatial continuity was modeled, ordinary block kriging was performed to generate geochemical maps. Indicator block kriging also was used as an alternative in analyzing and interpreting geochemical data. A novel approach is proposed, which combines both ordinary and indicator kriging for delineating geochemical anomalies. Probability maps proved to be appropriate for selecting new sites for further exploration. Gold anomalies in soils trending NE were well defined by geostatistical analysis and subsequently confirmed by drilling. 相似文献
8.
9.
Ling Yin 《International journal of geographical information science》2013,27(5):742-761
Exploring the evolution of people’s social interactions along with their changing physical locations can help to achieve a better understanding of the processes that generate the relationships between physical distance and social interactions, which can benefit broad fields of study related to social networks. However, few studies have examined the evolving relationships between physical movements and social closeness evolution. This is partially related to the shortage of longitudinal data in both physical locations and social interactions and the lack of an exploratory analysis environment capable of effectively investigating such a process over space and time. With the increasing availability of sociospatiotemporal data in recent years, it is now feasible to examine the relationships between physical separation and social interactions at the individual level in a space–time context. This research was intended to offer a spatiotemporal exploratory analysis approach to address this challenge. The first step was to propose the concept of a social closeness space–time path, which is an extension of the space–time path concept in time geography, to represent evolving human relationships in a social closeness space. A space–time geographical information system (GIS) prototype was then designed to support the representation and analysis of space–time paths in both physical and social closeness spaces. Finally, the effectiveness of the proposed concept and design in gaining insight into the impact of physical migration on online social closeness was demonstrated through an empirical study. The contributions of this study include an extension of the time–geographic framework from physical space to social closeness space, the development of a multirepresentation approach in a GIS to integrate an individual’s space–time paths in both physical and social closeness spaces, and an exploratory analysis of the evolving relationships between physical separation and social closeness over time. 相似文献
10.
Tropical Africa is often seen to have problem economies that are very much alike and suffer from the same development problems. This view is questioned in exploratory analyses of levels of wealth, spatial productivity, the structure of the economy and aspects of the openness of economies and the way they have changed between 1965 and 1995. The analyses reveal differences between economies in both degree and kind. Change to economies was not unidirectional so that they became more disparate and differentiated. The exploratory analyses were extended using factor analysis as a diagnostic tool on a 19-variable by 25 country data set for 1985, 1990 and 1995. This confirmed the findings of the exploratory analyses and revealed changes in the structure of the factors reflecting development in the period. The results are discussed in the context of the literature in a search for explanation and policy formulation. 相似文献
11.
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. 相似文献
12.
MITCHELL MOREHART FIONN MURTAGH JEAN-LUC STARCK 《International journal of geographical information science》2013,27(6):557-576
A foundation is set forth for use of the wavelet transform as a spatial analysis tool for modelling the geographical representation of economic and financial measures used in agriculture. This provides a framework from which to estimate a smooth nonparametric function which describes complex, multivariate relationships embedded in spatial data, with the resulting maps conveying large amounts of information in a familiar format. We illustrate this approach for tasks which include the graphical presentation of information, density estimation and wavelet-based nonparametric regression. A redundant wavelet transform is used, and we detail the properties which make it particularly appropriate for these objectives. 相似文献
13.
植物气候生态位及三维空间分布的图示化--以水青冈属为例 总被引：8，自引：1，他引：7
以水青冈属为例,应用多元统计分析方法和原理,借助计算机作图软件,实现了植物分布在综合气候因素中的直观表达,使不同物种的气候生态位的比较成为可能,应用空间统计学方法和原理,在计算机空间分析软件和作图功能的支持下,实现了植物三维空间分布的表达。 相似文献
14.
Donald W. Buckwalter 《The Professional geographer》2017,69(1):94-106
Journey-to-work mode choice is intertwined with ideological and pragmatic issues. This article reexamines such issues using socioeconomic data from the decennial census and American Community Survey (ACS). It investigates the structure of variables with exploratory data analysis (EDA) because this technique advises the formation of hypotheses and the specification of cause and effect. Traditional EDA reveals the nonnormal structure of raw data, mapping illustrates associations between transit and income, and both methods suggest the presence of a transit-by-choice population among affluent metropolitan residents. The results yield three hypotheses concerning propensity to use transit that have previously received little attention. 相似文献
15.
This research seeks to contribute to advancing qualitative methodologies at the intersection of qualitative geographic information systems (GIS), narrative analysis, 3D GIS-based time-geographic methods, and computer-aided qualitative data analysis. The approach to GIS-based narrative analysis developed in the study, called “geo-narrative,” is based on extending current GIS capabilities for the analysis and interpretation of narrative materials such as oral histories, life histories, and biographies. The three central elements in this approach are (1) narrative analysis as the qualitative approach; (2) 3D GIS-based time-geographic methods as the representational framework; and (3) 3D-VQGIS as the GIS-based computer-aided qualitative data analysis component. A case example based on a study of the lives of the Muslim women in Columbus, Ohio, after 11 September 2001 is used to illustrate the approach. 相似文献
16.
Ayse Can 《International journal of geographical information science》2013,27(8):1009-1017
Abstract This paper reports on software to construct alternative weight matrices and to compute spatial autocorrelation statistics, namely the Moran coefficient and the Geary coefficient using Arc/Info’s data structure. As such it is an addition to recent efforts in linking GIS with exploratory spatial data analysis. The software is interfaced with Arc/Info via the Arc Macro Language (AML) so that it can be run in the ARC environment. This allows the user to perform exploratory analysis within GIS which may provide insights in subsequent spatial analysis and modelling. 相似文献
17.
Vincent B. Robinson 《The Professional geographer》1978,30(2):174-179
This paper addresses the question of how far into the past previous land-use patterns provide significant information concerning present or future patterns. The provision of information is viewed as a reduction in uncertainty. An information-theoretic approach that permits both statistical and graphical analysis is suggested. Application of this method to the analysis of land-use change in three townships on the fringe of Akron, Ohio suggests that, to a varying degree, the processes of change are first-order Markov processes. 相似文献
18.
Robert Haining 《The Professional geographer》1990,42(3):336-344
A simple graphical method for developing regression models for spatially referenced data is presented. The method supplements formal testing procedures and provides the analyst with useful information helpful in developing an understanding of data properties without the need for complex data manipulations. The paper includes a worked example and suggests directions for further work in this area. 相似文献
19.
The airline industry in the United States has experienced significant changes in the spatial configuration of networks since the Airline Deregulation Act of 1978. Attempts have been made to study the structure of the hub-and-spoke network in the airline industry, but no efficient methodology has been available. This paper describes an exploratory approach to analyzing the spatial configuration of airline networks. Flight frequencies and numbers of passengers from published schedules of six U.S. domestic airlines (American, Continental, Delta, Northwest, United, and USAir) are used in this study. The analytic components in the exploratory system include the examination of network connectivity and network autocorrelation in a dynamic mapping environment. The results of the analyses show both the overall spatial patterns of airline networks and the hierarchical hubbing structures. 相似文献
20.
新时期中国农村发展动态与区域差异格局 总被引：4，自引：2，他引：2
本文以2000、2004、2008中国31个省际农村发展指标面板数据,采用探索性因子分析的方法,对新时期中国农村发展状态的区域差异进行综合分析。从空间格局来看,东、中、西三大地带的农村发展具有明显的地域差异,农村发展的差异格局并未发生明显变化,东部〉中部〉东北〉西部的格局依旧存在,农村的发展水平与区域经济发展水平存在一致性,自然资源禀赋与历史经济发展水平是中国农村发展区域差异基础,农村主体特征与区域发展阶段是导致农村发展区域差异的主要原因,偏向性的政府政策与全球性因素是强化区域差异的重要动力,而各地差异性的农村产业转型过程,是助推中国农村发展区域差异的核心机制。2000、2004和2008年中国农村发展差异度分别为0．356、0．413、0．386,这表明,自2000年以来区域农村发展差异先拉大后缩小,总体上呈现扩大趋势,这是长期以来区域发展外部环境与农村自我发展能力综合作用的结果。从2000—2008年中国农村发展“重心”移动的轨迹可以看出,中国农村发展的重心落在安徽省内,农村发展水平东西差异明显,2000．2004年,中国农村发展水平的重心向北移动,北方地区的农村发展速度较快;2004—2008年,中国社会主义新农村建设的战略部署和西部大开发战略的稳步推进,中国农村发展水平的东西差异有了一定缓和,重心向西南方向移动。 相似文献