An initial formal model for spatial data infrastructures

The Commission on Spatial Data Standards of the International Cartographic Association is working to define formal models and technical characteristics of Spatial Data Infrastructures (SDI). To date, this work has been restricted to the Enterprise and Information Viewpoints from the ISO Reference Model for Open Distributed Processing standard. The Commission has developed models for these two viewpoints. These models describe how the different parts of an SDI fit together in the viewpoints in question. These models should be seen as a contribution towards the overall model of the SDI and its technical characteristics. During the model development process, the roles of the different Actors in an SDI in the Enterprise and Information Viewpoints have also been identified in Use Case diagrams of an SDI. All the models have been developed using the Unified Modeling Language.     

基于ESDA的河南艾滋病空间格局

以2008 年河南省地级市艾滋病分布数据为基础,利用ESDA空间数据挖掘的方法,对河南省艾滋病空间格局进行全面分析。结果表明：① 综合考虑河南省18 个地级市艾滋病确诊人数数据的空间自相关分析结果和不同传播途径感染单因素空间格局的结果,将河南艾滋病感染区域分为以FPD感染途径为主的豫南、豫东南高度流行区和以高危行为传播途径为主的豫北低度流行区;② 河南省艾滋病感染途径分布中,FPD感染、母婴感染、异性传播感染和注射吸毒传播具有明显的空间正相关,而同性传播途径与输血感染则显示出较大的空间随机分布特征;③ 与FPD 感染存在空间正相关的为注射吸毒传播、异性传播以及母婴传播方式,输血、同性以及其他方式传播途径与FPD感染途径分布不存在空间相关性。     

An exploratory spatial data analysis of low birth weight prevalence in Georgia

Low birth weight (LBW), defined as a live birth weighing less than 2500 g, is a significant public health problem in the United States, but the complex nature of the etiology of this problem is not fully understood. Moreover, significant disparities in LBW prevalence are well documented among certain populations, particularly in minority and underserved communities. The identification of spatial patterns of LBW prevalence is a critical first step in a more complete understanding of the epidemiology of this public health challenge and these techniques are instrumental in designing valid observational and analytical studies to more fully study the problem. This paper examines the spatial patterns of LBW prevalence, as well as the presence of spatial clusters in the State of Georgia at both the county and census tract levels. Unadjusted and empirical Bayes smoothed LBW rates were mapped to visualize the spatial variation of LBW rates, and the Moran’s I statistic and the Local Indicator of Spatial Association (LISA) statistic were computed to assess the degree of spatial dependence in the LBW rates. Results revealed marked geographical variation in LBW prevalence in Georgia in 2000. In addition, these data validate the significant disparity (two-fold difference) between white and black racial subgroups as documented in the literature. Trends associated with positive and negative spatial autocorrelations illustrated variation with respect to race. Limitations of data and methods, as well as plans for utility of the results of this study for further investigation were discussed.