城市地质信息系统及其应用

本文提出了城市地质信息系统的总体结构,系统划分为数据层、应用层和服务层三个层次。由信息数据录入与管理子系统、三维地质体建模子系统、数据共享与社会化服务子系统构成。然后分数据库和业务应用系统两个部分阐述了系统的开发方案,并说明了高精度三维地质模型快速构建、大数据量模型运行和多元数据一体化显示这三个关键技术的解决方案。     

“3S”技术在农作物秸秆焚烧监测中的应用

介绍了“3S”技术在农作物秸秆焚烧监测中应用的一般原理和方法，包括利用RS技术监测焚烧农作物秸秆火点，判定农作物 进入收割期； 利用GIS技术确定卫星遥感监测焚烧农作物秸秆火点的性质和对火点信息进行分析管理； 利用GPS技术指导查找验证火 点的具体位置等。同时，还介绍了国家卫星气象中心近年来采用“3S”技术监测农作物秸秆焚烧的概况。     

Analysis of a spatial distribution of landslides triggered by the 2004 Chuetsu earthquakes of Niigata Prefecture, Japan

On October 23, 2004, a series of powerful earthquakes with a maximum M _w = 6.6 located near the western coast of northern Honshu struck parts of northern Japan, particularly Niigata Prefecture; these earthquakes were known as the Chuetsu event. Thousands of landslides, as a secondary geotechnical hazard associated with these earthquakes, were triggered over a broad area; these landslides were of almost all types. The purpose of this study was to detect correlations between landslide occurrence with geologic and geomorphologic conditions, slope geometry, and earthquake parameters using two indexes based on Geographic Information Systems (GIS). In the study area, the landslide–area ratio (LAR), which is defined as the percentage of the area affected by landslides, was 2.9%, and the landslide concentration (LC), the number of landslides per square kilometer, was 4.4 landslides/km², which is much more than other reported cases of seismic activity with the same magnitude. This was possibly due to heavy rainfall just before the Chuetsu earthquakes. Statistical analyses show that LAR has a positive correlation with slope steepness and distance from the epicenter, while LC is inversely correlated with distance from the epicenter. The Wanazu Formation had the most concentrated landslide activity, followed by the Kawaguchi, Ushigakubi, Shiroiwa and Oyama Formations, although the Wanazu Formation occupied only 4.5% of the total area of geological units. With 8.2% of the area affected by seismic landslides, the Kawaguchi Formation had the highest LAR. It was followed by the Shiroiwa, Ushigakubi and Wanazu Formations with LAR ranging from 4.6% to 6.0%. For lots of geological subunits, landslides are more frequent in a range of slope angles between 15° and 40°. The susceptibility to landsliding of each geologic unit was thus evaluated to correlate with slope steepness. It was also noted that the effects of the earthquakes were made far worse by antecedent rainfall conditions induced by a␣typhoon, and further research emphasizing the role of antecedent rainfall was discussed.     

Topographic relations: developing a heuristic device for conceptualising networked relations

This paper considers whether the deployment of a topographical metaphor may add value to the recent discussion of networked relations. The paper discusses how viewing relations as part of a relational landscape may add a third dimension to the discussion by allowing an appreciation of the strength, or entrenchment, of relations, and how these entrenchments impact on the development of new relations and the resistance to watershed events. The heuristic device is explored through the case of air survey in the 1920s and 1930s. This illustrative case demonstrates how relations are held together, resisted and reformed to different degrees depending on the varying topography of the relational landscape.     

岩质边坡的关键块体稳定性影响因素的敏感性研究

岩质边坡的关键块体是边坡安全分析和支护设计的重要方面,影响关键块体稳定性的因素较多,本文结合正交试验设计方法,对影响关键块体稳定的重要因素进行敏感性分析,评价不同物理力学参数对关键块体的安全系数的影响程度,为工程提供合理的意见。     

Geographical location in the information age: from destiny to opportunity?

This article argues for a possibly new significance of geographical location in the information age, a significance amounting to more than mere spatial anchoring, on the one hand, and to less and different than absolute destiny, on the other. Hence, we show a possible change in the significance of geographical location from destiny in the industrial age to potential opportunity in the information age, a transition which applies to geographical units (i.e. cities, regions) and to individuals. First we discuss geographical location as destiny in the industrial age for both geographical entities and individuals. Second, we highlight a transitional period spanning through the 1970s and 1980s during which geographical location lost much of its absolute nature, becoming more of an anchor. Third, we present a conceptual framework for geographical location possibly turning into opportunity in the information age, again for both geographical units and individuals. We demonstrate that this potential opportunity has only partially materialized by individuals in the international use of online shopping, showing that their adoption is wider in North America, and differentiated in Europe. We further demonstrate a partial dissemination of opportunities for cities and regions by focusing on FDI. Finally, in the fourth and concluding section, we briefly discuss pertaining policy issues for the enhancement of locational opportunities.     

基于三角形的多边形内点自动生成算法

根据多边形内点的作用,多边形内点与多边形的一一对应关系是多边形内点生成算法的关键。在分析现有算法的基础上,提出了基于三角形的多边形内点自动生成算法,该算法简单易行,具有确定性,保证了生成的多边形内点与多边形的一一对应关系。     

Revisiting prior distributions,Part II: Implications of the physical prior in maximum entropy analysis

The well-known “Maximum Entropy Formalism” offers a powerful framework for deriving probability density functions given a relevant knowledge base and an adequate prior. The majority of results based on this approach have been derived assuming a flat uninformative prior, but this assumption is to a large extent arbitrary (any one-to-one transformation of the random variable will change the flat uninformative prior into some non-constant function). In a companion paper we introduced the notion of a natural reference point for dimensional physical variables, and used this notion to derive a class of physical priors that are form-invariant to changes in the system of dimensional units. The present paper studies effects of these priors on the probability density functions derived using the maximum entropy formalism. Analysis of real data shows that when the maximum entropy formalism uses the physical prior it yields significantly better results than when it is based on the commonly used flat uninformative prior. This improvement reflects the significance of the incorporating additional information (contained in physical priors), which is ignored when flat priors are used in the standard form of the maximum entropy formalism. A potentially serious limitation of the maximum entropy formalism is the assumption that sample moments are available. This is not the case in many macroscopic real-world problems, where the knowledge base available is a finite sample rather than population moments. As a result, the maximum entropy formalism generates a family of “nested models” parameterized by the unknown values of the population parameters. In this work we combine this formalism with a model selection scheme based on Akaike’s information criterion to derive the maximum entropy model that is most consistent with the available sample. This combination establishes a general inference framework of wide applicability in scientific/engineering problems.     

Enhancing a GIS Cellular Automata Model of Land Use Change: Bayesian Networks, Influence Diagrams and Causality

Cellular Automata (CA) models at present do not adequately take into account the relationship and interactions between variables. However, land use change is influenced by multiple variables and their relationships. The objective of this study is to develop a novel CA model within a geographic information system (GIS) that consists of Bayesian Network (BN) and Influence Diagram (ID) sub‐models. Further, the proposed model is intended to simplify the definition of parameter values, transition rules and model structure. Multiple GIS layers provide inputs and the CA defines the transition rules by running the two sub‐models. In the BN sub‐model, land use drivers are encoded with conditional probabilities extracted from historical data to represent inter‐dependencies between the drivers. Using the ID sub‐model, the decision of changing from one land use state to another is made based on utility theory. The model was applied to simulate future land use changes in the Greater Vancouver Regional District (GVRD), Canada from 2001 to 2031. The results indicate that the model is able to detect spatio‐temporal drivers and generate various scenarios of land use change making it a useful tool for exploring complex planning scenarios.     

GIS与OA集成技术研究

本文介绍了GIS与OA集成的背景,分析了四种GIS与OA松散式集成方法的优缺点。在此基础上,根据GIS与OA的无缝集成的需要,提出了GIS与OA集成一体化数据管理的方法,在保证数据安全管理与统一控制的条件下,研究了基于组件、基于中间件、基于Web Service、基于本体等多种GIS与OA的无缝集成技术。最后,简要介绍了GIS和OA集成技术的实践情况。