The convergence of GIS and social media: challenges for GIScience

It is hard to believe that 10 years have passed since we wrote our guest editorial for IJGIS (Sui and Goodchild 2001 Sui, D.Z. and Goodchild, M.F. 2001. Are GIS becoming new media?. International Journal of Geographical Information Science, 15(5): 387–390. [Taylor & Francis Online], [Web of Science ®] , [Google Scholar]). Using the nascent evidence that emerged in the late 1990s, we speculated back in 2001 that geographic information systems (GIS) were rapidly becoming part of the mass media. On the basis of the proposition of GIS as media, we were able to link GIScience with theories in media studies such as Marshall McLuhan's law of the media, which considers modern media as modifiable perceptive extensions of human thought (Sui and Goodchild 2003 Sui, D.Z. and Goodchild, M.F. 2003. A tetradic analysis of GIS and society using McLuhan's law of media. Canadian Geographers, 47(1): 5–17. [Crossref], [Web of Science ®] , [Google Scholar]). Remarkable conceptual and technological advances in GIS have been made during the past 10 years. The goal of this review is to provide an update on the ‘GIS as media’ argument we made 10 years ago and to discuss the new challenges for GIScience posed by the growing convergence of GIS and social media.     

基于偏移四叉树投票的“大尺寸”点状符号多尺度无压盖可视化

为解决Web 2.0环境下点状符号地图混搭中的制图问题,本文研究并实现了一种可100%避免压盖的"大尺寸"点符号高效可视化方法。该方法的核心思想是四叉树网格单选,采用网格平移对多次单选结果投票来计算符号在各缩放级别的显著性等级,可解决符号在相邻网格的空间冲突。该过程不需要显式探测冲突,因而处理效率极高。随着地图放大,重要性较低的符号也逐级显现,实现了语义层次的多尺度表达。针对符号和网格大小比率关系、有效网格平移方案及图面利用率不足问题提出两种扩展:格网增选和多级符号叠加。对方法的可行性进行了试验验证,并分析了该方法在用户查询条件改变下的稳定性和不同数据量下的伸缩性(非优化实现可达到105量级数据的亚秒级处理)。     

Service contracts—An instrument of international logistics supply chain: Under United States and European Union regulatory frameworks

Service contracts have emerged as an important instrument to secure a long-term relationship between carriers in the container shipping industry and shippers requiring scheduled services covering a global market. This contract, entered into largely on an individual and confidential basis, continues to enjoy anti-trust immunity under current United States and European Union regulations. It will continue to be in place even after the EC Council Regulation 4056/86 is repealed in October 2008 although it may operate in a modified way because of the absence of the common external conference tariff. This article examines the implications of this instrument on the international supply chain and explores its future role in defining efficiencies in international trade flows.     

检索词优化与空间自适应的深网POI获取方法研究

针对检索词库构建困难、数据请求量受限制等相关问题,该文提出一种基于独立覆盖率排序和空间自适应剖分的深网POI信息搜索方法,通过候选检索词初步构建、贪婪式探测搜索、检索词优化降维、空间自适应剖分爬行等主要流程,利用逐步逼近POI搜索的最大覆盖最优解,实现对深网POI信息的全量获取,大幅度提高深网POI数据的召回率与采集效率,该方法对于丰富地理信息资源、提升空间信息服务与内容管理能力具有重要意义。     

基于Web的地图符号设计与实现

地图符号化是当前数字地图研究的重要内容之一。着重论述了Web环境下地图符号的构成特征、地图符号的组织及符号配置,以及符号库的基本传输方法,最后给出具体实例,说明了该实践的有效性与可行性。     

Constructing geo-information sharing architecture

IntroductionAlong with the development of computer andInternet technology , GIS applications are be-coming broad increasingly ,geo-information sha-ring are of increasingi mportance ,and geo-infor-mationinteroperabilityis the trend in the futureGIS applica…     

网络环境下分级统计地图可视化方法的研究

从空间认知的角度分析和研究了分级统计地图可视化技术,并在网络环境下,实现了分级统计地图制图系统,让用户在一个交互的、可视化的制图环境中定制个性化地图,同时可以利用系统提供的可视化工具进行探索性的空间数据分析,发现统计数据内在的知识.     

基于ArcGIS Server的分布式GIS应用

ArcGIS Server是ESRI在ArcGIS 9.0系列产品中推出的一个创建企业级GIS应用的平台。它的出现使得分布式GIS应用进入到一个新的领域,不仅仅是数据的共享,而且高级的GIS功能如制图、空间分析和地理编码、多用户编辑等也能够通过Internet/Intranet为普通用户所拥有。文中介绍了相关的概念并分析了ArcGIS Server的体系结构,在此基础上通过实例展示了基于ArcGIS Server构建分布式GIS应用的可行性。     

基于Servlet服务链的分布式Web GIS研究

本文从Servlet技术出发,探讨了Servlet技术在Web GIS服务器实现上的优势。针对目前分布式Web GIS中面临的数据和信息的分布存储、地理信息难以整合、多用户并发访问瓶颈等问题;探讨了通过构建Servlet服务链来实现分布式Web GIS的体系架构,基于Servlet服务链的分布式空间数据的调度与管理,Web GIS服务器端GIS Servlet服务链的构建。最后,通过实验验证了多Servlet服务链在Web GIS中分布数据处理,服务中多用户并发访问等方面的优势。     

A Task-Based Ontology Approach to Automate Geospatial Data Retrieval

This paper presents a task‐based and Semantic Web approach to find geospatial data. The purpose of the project is to improve data discovery and facilitate automatic retrieval of data sources. The work presented here helps create the beginnings of a Geospatial Semantic Web. The intent is to create a system that provides appropriate results to application users who search for data when facing tasks such as emergency response or planning activities. In our task‐based system, we formalize the relationships between types of tasks, including emergency response, and types of data sources needed for those tasks. Domain knowledge, including criteria describing data sources, is recorded in an ontology language. With the ontology, reasoning can be done to infer various types of information including which data sources meet specific criteria for use in particular tasks. The vision presented here is that in an emergency, for example, a user accesses a Web‐based application and selects the type of emergency and the geographic area. The application then returns the types and locations (URLs) of the specific geospatial data needed. We explore the abilities and limitations of the OWL Web Ontology Language along with other Semantic Web technologies for this purpose.