GeoDa : An Introduction to Spatial Data Analysis

This article presents an overview of GeoDa™, a free software program intended to serve as a user-friendly and graphical introduction to spatial analysis for non-geographic information systems (GIS) specialists. It includes functionality ranging from simple mapping to exploratory data analysis, the visualization of global and local spatial autocorrelation, and spatial regression. A key feature of GeoDa is an interactive environment that combines maps with statistical graphics, using the technology of dynamically linked windows. A brief review of the software design is given, as well as some illustrative examples that highlight distinctive features of the program in applications dealing with public health, economic development, real estate analysis, and criminology.     

SPATIAL ECONOMETRIC MODELING OF ORIGIN‐DESTINATION FLOWS*

ABSTRACT Standard spatial autoregressive models rely on spatial weight structures constructed to model dependence among n regions. Ways of parsimoniously modeling the connectivity among the sample of N=n² origin‐destination (OD) pairs that arise in a closed system of interregional flows has remained a stumbling block. We overcome this problem by proposing spatial weight structures that model dependence among the N OD pairs in a fashion consistent with standard spatial autoregressive models. This results in a family of spatial OD models introduced here that represent an extension of the spatial regression models described in Anselin (1988) .     

A Structural Equation Approach to Models with Spatial Dependence

We introduce the class of structural equation models (SEMs) and corresponding estimation procedures into a spatial dependence framework. SEM allows both latent and observed variables within one and the same (causal) model. Compared with models with observed variables only, this feature makes it possible to obtain a closer correspondence between theory and empirics, to explicitly account for measurement errors, and to reduce multicollinearity. We extend the standard SEM maximum likelihood estimator to allow for spatial dependence and propose easily accessible SEM software like LISREL 8 and Mx. We present an illustration based on Anselin's Columbus, OH, crime data set. Furthermore, we combine the spatial lag model with the latent multiple-indicators–multiple-causes model and discuss estimation of this latent spatial lag model. We present an illustration based on the Anselin crime data set again.     

Beyond Moran's I: Testing for Spatial Dependence Based on the Spatial Autoregressive Model

The statistic known as Moran's I is widely used to test for the presence of spatial dependence in observations taken on a lattice. Under the null hypothesis that the data are independent and identically distributed normal random variates, the distribution of Moran's I is known, and hypothesis tests based on this statistic have been shown in the literature to have various optimality properties. Given its simplicity, Moran's I is also frequently used outside of the formal hypothesis-testing setting in exploratory analyses of spatially referenced data; however, its limitations are not very well understood. To illustrate these limitations, we show that, for data generated according to the spatial autoregressive (SAR) model, Moran's I is only a good estimator of the SAR model's spatial-dependence parameter when the parameter is close to 0. In this research, we develop an alternative closed-form measure of spatial autocorrelation, which we call APLE , because it is an approximate profile-likelihood estimator (APLE) of the SAR model's spatial-dependence parameter. We show that APLE can be used as a test statistic for, and an estimator of, the strength of spatial autocorrelation. We include both theoretical and simulation-based motivations (including comparison with the maximum-likelihood estimator), for using APLE as an estimator. In conjunction, we propose the APLE scatterplot, an exploratory graphical tool that is analogous to the Moran scatterplot, and we demonstrate that the APLE scatterplot is a better visual tool for assessing the strength of spatial autocorrelation in the data than the Moran scatterplot. In addition, Monte Carlo tests based on both APLE and Moran's I are introduced and compared. Finally, we include an analysis of the well-known Mercer and Hall wheat-yield data to illustrate the difference between APLE and Moran's I when they are used in exploratory spatial data analysis.     

A History of the Concept of Spatial Autocorrelation: A Geographer's Perspective

Spatial autocorrelation is a concept that helps to define the field of spatial analysis. It is central to studies using spatial statistics and spatial econometrics. In this paper, we trace the early development of the concept and explain the academic links that brought the concept to the fore in the late 1960s. In geography, the importance of the work of Michael F. Dacey, Andrew D. Cliff, and J. Keith Ord is emphasized. Later, with the publication of a volume on spatial econometrics by Luc Anselin, spatial research and the use of the concept of spatial autocorrelation received a considerable boost. These developments are outlined together with comments about recent and possible future trends in spatial autocorrelation-based research.     

空间生产视角下我国城市行政区划调整的三元互动逻辑

在空间生产的视角下,行政区划调整不仅包括地域层面上对城市空间的重新划分,而且包括尺度层面上对社会关系和制度结构的系统重塑。将政府、市场与社会的行动和权力、资本、权利的三重逻辑整合起来,可以为分析城市行政区划调整提供一个全新的工具。在实践中,合作与互制是政府（权力）和市场（资本）的互动逻辑,监督与回应是政府（权力）和社会（权利）的互动逻辑,嵌入与互渗是市场（资本）和社会（权利）的互动逻辑。城市行政区划的调整不仅是政府、市场、社会主体相互博弈的结果,而且会不断重塑三类主体自身以及相互关系。     

Implementing Spatial Data Analysis Software Tools in R

This article reports on work in progress on the implementation of functions for spatial statistical analysis, in particular of lattice/area data in the R language environment. The underlying spatial weights matrix classes, as well as methods for deriving them from data from commonly used geographical information systems are presented, handled using other contributed R packages. Since the initial release of some functions in 2001, and the release of the spdep package in 2002, experience has been gained in the use of various functions. The topics covered are the ingestion of positional data, exploratory data analysis of positional, attribute, and neighborhood data, and hypothesis testing of autocorrelation for univariate data. It also provides information about community building in using R for analyzing spatial data.     

SEISMIC BEHAVIOUR OF PERIMETER AND SPATIAL STEEL FRAMES

The present study deals with the seismic performance of partial perimeter and spatial moment resisting frames (MRFs) for low-to-medium rise buildings. It seeks to establish perimeter configuration systems and hence the lack of redundancy can detrimentally affect the seismic response of framed buildings. The paper tackles this key issue by com-paring the performance of a set of perimeter and spatial MRFs, which were “consistently designed”. The starting point is the set of low-(three-storey) and medium-rise (nine-storey) perimeter frames designed within the SAC Steel Project for the Los Angeles, Seattle and Boston seismic zones. Extensive design analyses (static and multi-modal) of the perimeter frame buildings and consistent design of spatial frame systems, as an alternative to the perimeter configuration, were conducted within this analytical study. The objectives of the consistent design are two-fold, i.e. obtaining fundamental periods similar to those of the perimeter frames, i.e. same lateral stiffness under design horizon-tal loads, and supplying similar yield strength. The seismic behaviour of perimeter and spatial configuration structures was evaluated by means of push-over non-linear static analyses and inelastic dynamic analyses (non linear time histories). Comparisons be-tween analysis results were developed in a well defined framework since a clear scheme to define and evaluate relevant limit states is suggested. The failure modes, either local or global, were computed and correlated to design choices, particularly those concerning the strength requirements (column overstrength factors) and stiffness (elastic stability indexes). The inelastic response exhibited by the sample MRFs under severe ground motions was assessed in a detailed fashion. Conclusions are drawn in terms of local and global performance, namely global and inter-storey drifts, beam and column plas-tic rotations, hysteretic energy. The finding is that the seismic response of perimeter and spatial MRFs is fairly similar. Therefore, an equivalent behaviour between the two configurations can be obtained if the design is “consistent”.     

Virtual zooarchaeology: building a web-based reference collection of northern vertebrates for archaeofaunal research and education

Osteological reference collections are a crucial tool in archaeofaunal analysis, but few are comprehensive; most lack a broad range of taxa or multiple individuals per taxon. This problem is especially prominent in arctic zooarchaeology, where difficulty in obtaining, transporting, and processing northern taxa has led to a dearth of appropriate reference collections. The Virtual Zooarchaeology of the Arctic Project, or VZAP, seeks to develop a comprehensive virtual comparative assemblage for the skeletons of northern vertebrates. VZAP (http://vzap.iri.isu.edu) is designed to assist with identifications in the lab or field and provides significant educational value, for both classroom demonstration and personal consultation. The VZAP website presents high-resolution digital photographs and 3D models of skeletal elements via an intuitive graphical user interface, designed to mimic the visual experience of working with a real comparative collection. This custom-built interface, the Dynamic Image Engine, represents a new way to present heritage media in an interactive and engaging format. VZAP also implements unique 3D scanning protocols to increase the realism of 3D models, and delivers them on a platform that allows for point to point measurements, cross-sections, morphological labels, and anatomical orientations.     

ChoroWare: A Software Toolkit for Choropleth Map Classification

Choropleth mapping plays an important role in exploratory spatial data analysis. Several objectives have been suggested to guide choropleth map construction. These objectives, however, often conflict and, consequently, a choropleth map that is best for one objective may not be best for others. Choosing a set of choropleth class intervals is thus a multiobjective problem. This article describes an open-source software toolkit, called ChoroWare that is designed to help cartographers identify class intervals that are suitable for a specific application. The software uses a genetic algorithm to generate a set of nondominated solutions to the multiobjective choropleth class interval problem and uses an interactive visualization tool to display members of this classification set. Using ChoroWare, cartographers can examine trade-offs between alternatives and find desirable choropleth classifications that meet their objectives.     

Detecting modes in low-dimensional archaeological data

An approach to testing for modes in low-dimensional data, Silverman’s test, novel in an archaeological setting, is described and illustrated. ‘Patterns’ in archaeological data can be suggested by the presence of modes. Reassurance is needed that modes suggested by graphical analysis are genuine before attempting substantive archaeological interpretation. The test either provides such reassurance, or else guards against over-interpretation, particularly with small samples. Data on loomweight dimensions, lead isotope ratios, and ceramic compositions are used to illustrate use of the test, dealing with issues concerning outliers and small samples as they arise. The focus is on univariate mode detection.     

Package FLUIDS. Part 3: correlations between equations of state, thermodynamics and fluid inclusions

The computer package FLUIDS ( Bakker 2003 ) has been revised to calculate fluid properties in pores and inclusions. The programs are provided with a Graphical User Interface (GUI) and are adapted to new operating systems, including MacOS, Windows and Linux. The van der Waals equation of state has been added to the group Loners and is used to illustrate a large variety of calculation procedures for many thermodynamic parameters and properties. The mathematical transformations can be applied to any equation of state with the form p ( V , T , n ), i.e. the pressure of a multi-component fluid is expressed as a function of volume, temperature and amount of substance. The fluid properties that are usually observed in microthermometric analyses of fluid inclusions, such as phase separation, phase coexistence and stability, can be predicted with these equations of state by using its spinodal and critical point calculations, in addition to fugacity calculations of liquid and vapour phases. The computer program LonerW can be freely downloaded from the website: http://fluids.unileoben.ac.at/Computer.html .     

When Survey Goes East: Field Survey Methodologies and Analytical Frameworks in a Central Asian Context

This paper investigates the applicability and transferability of conventional frameworks of archaeological survey in the context of marginal alluvial environments, particularly the unique inland deltas of Central Asia. These dynamic and visually obstructed landscapes pose unique challenges not only to survey methodologies but also to theory and interpretation. Here, an exploratory approach to data analysis is used that applies three distinct yet integrated methodologies: visibility analysis, multi-scalar spatial analysis and directional (anisotropic) statistics. This approach thereby moves beyond many of the existing conceptual constraints about how we understand surface distributions in arid alluvial landscapes and ultimately identifies both transferable analytical methods and new fieldwork agendas that are relevant to a wide range of survey projects.     

Potential Contributions of Spatial Analysis to Geographic Information Systems for Transportation (GIS-T)

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.     

基于手机信令数据的城市时间活力模式及影响因素研究——以南京市中心城区为例

本文基于手机信令数据从时间维度诠释城市活力的概念,并构建其评价指标体系。研究从活动强度、活动混合度、活动联系强度三个维度测度城市活力,在此基础上通过对一日24小时的城市活力时间序列进行聚类,得出五种城市时间活力模式,并构建计量模型分析社会经济和建成环境对不同时间活力模式的影响。主要结论有：(1)南京市中心城区城市时间活力模式可分为高活力波动型、高活力稳定型、中活力波动型、中活力稳定型和低活力稳定型五类;(2)不同时间活力模式在空间上的分布具有一定规律,高活力波动型时间活力模式多位于区域就业中心与公共服务、商业服务中心附近;(3)影响因素方面,居住人口密度、年龄结构、经济水平、交通区位、功能性质、开发强度均对高活力波动/稳定型街区的形成有促进作用。研究从时间维度扩展了城市活力的研究视角,可为探索城市时空间规划、保障城市高质量可持续发展提供重要参考。     

Comment réorganiser le réseau postal suisse? Une application de l'aide à la décision territoriale

How to reorganize the Swiss postal network? A case study of spatial decision making‐support. This article presents a case study of spatial decision making‐support in relation to the Swiss Post and its efforts to reorganize the postal network in eight Swiss cities. The first part of the article describes the methodology and highlights selected original elements used in the processing of geographic information (spatial analysis and multi‐criteria analysis). The second part, more analytical, examines the process used to apply the method defined in the previous section. Based on a constructivist approach of decision‐support, it explores the modes of interaction between available information and decision makers. The analysis shows that the decision maker is relatively difficult to identify since the decision making process includes a set of partial and dependent decisions that are taken by a diversity of people. In conclusion, geographic information played an important role, not only on the decision, but mainly in allowing decision makers to better understand spatial complexity     

TECHNICAL NOTE A FRAMEWORK FOR MULTI-SITE DISTRIBUTED SIMULATION AND APPLICATION TO COMPLEX STRUCTURAL SYSTEMS

In this technical note, the development of a framework for multi-site distributed simulations is presented. The algorithm is suitable for any combination of physical (laboratory) and analytical (computer) distributed simulations of structures, their foundations and the underlying sub-strata subjected to static and dynamic loading. Two examples of multi-site testing and multi-platform simulation are given. The main contribution in this note is the separation between time-step integration and stiffness formulation, which enables the use of static analysis and testing as modules of the main control module referred to as the simulation coordinator. The approach proposed is intuitive, simple and efficient. It is therefore recommended for use in distributed analysis using different programs, distributed testing facilities (e.g. the NEES equipment sites) or a combination of analysis and testing.     

关中天水经济区核心—边缘旅游空间结构解析

核心—边缘结构是区域旅游空间结构演化的重要解释模型,本文从复杂系统理论和分形理论切入重新解构旅游空间结构演变特征、动态过程和测度方法。以关天经济区为例实证分析并得出结论:核心—边缘旅游空间结构具有层次性、涌现性和分形的特征,演变过程分为核心集聚极化、边缘扩散溢出和空间动态平衡三个阶段;首位度、分形等方法能很好揭示旅游空间结构演化过程;关天经济区旅游空间属于典型的核心—边缘结构,目前处于核心集聚极化阶段后期,溢出效应逐步显现,次级核心基本形成,空间结构与等级结构紧密耦合,发展态势良好。     

The future role of GIS education in creating critical spatial thinkers

Teaching of critical spatial thinking in higher education empowers graduates to effectively engage with spatial data. Geographic information systems (GIS) and science are taught to undergraduates across many disciplines; we evaluate how this contributes to critical spatial thinking. The discipline of GIS covers the whole process of spatial decision-making, but GIS modules often ignore the context setting of spatial problems, and just cover the technical aspects of how to use GIS software. We outline how some existing GIS practicals could be improved to focus on the development of critical spatial thinking skills, competences and abilities that are valuable to graduates.