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为了实现地理语义数据的快速有效的空间查询,通过分析传统RDF索引方法和空间索引方法的不足,结合两者提出一种基于空间四元组（GeoQuad）的地理语义空间索引构建方法,并基本该方法利用Jena和ARQ实现基于SPARQL语法的地理语义空间查询。实验表明,方法高效可行,不仅能够快速定位空间RDF节点,而且能够快速进行RDF空间查询并返回RDF结果。 相似文献
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Geographic information has become central for data scientists of many disciplines to put their analyzes into a spatio-temporal perspective. However, just as the volume and variety of data sources on the Web grow, it becomes increasingly harder for analysts to be familiar with all the available geospatial tools, including toolboxes in Geographic Information Systems (GIS), R packages, and Python modules. Even though the semantics of the questions answered by these tools can be broadly shared, tools and data sources are still divided by syntax and platform-specific technicalities. It would, therefore, be hugely beneficial for information science if analysts could simply ask questions in generic and familiar terms to obtain the tools and data necessary to answer them. In this article, we systematically investigate the analytic questions that lie behind a range of common GIS tools, and we propose a semantic framework to match analytic questions and tools that are capable of answering them. To support the matching process, we define a tractable subset of SPARQL, the query language of the Semantic Web, and we propose and test an algorithm for computing query containment. We illustrate the identification of tools to answer user questions on a set of common user requests. 相似文献
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基于XQuery的GML查询语言研究 总被引：4，自引：0，他引：4
随着GML规范的不断完善及GIS软件厂商的广泛支持,越来越多的空间数据以GML格式存储,GML空间数据的查询已成为GIS研究的热点问题。传统的关系数据库查询语言SQL是针对平面的二维关系数据而设计的,并不适合XML/GML半结构化数据的查询;商品化GIS软件的查询系统只能查询自身的空间数据而无法查询其它GIS系统的空间数据;XML查询的研究为GML查询奠定了一定的基础。首先针对GML查询存在的问题,提出了扩展XQuery是GML查询语言实现的最佳选择;结合XML查询语言和空间数据查询语言,提出了GML查询语言的特征和GML查询语言系统框架;并根据GML空间数据的特点,以XML标准查询语言XQuery为基础,提出了XQuery空间扩展的内容;开发了GML空间数据查询语言GMLXQL,实现了GML空间数据的本原查询。 相似文献
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《International Journal of Digital Earth》2013,6(5):383-402
Geospatial Semantic Web promises better retrieval geospatial information for Digital Earth systems by explicitly representing the semantics of data through ontologies. It also promotes sharing and reuse of geospatial data by encoding it in Semantic Web languages, such as RDF, to form geospatial knowledge base. For many applications, rapid retrieval of spatial data from the knowledge base is critical. However, spatial data retrieval using the standard Semantic Web query language – Geo-SPARQL – can be very inefficient because the data in the knowledge base are no longer indexed to support efficient spatial queries. While recent research has been devoted to improving query performance on general knowledge base, it is still challenging to support efficient query of the spatial data with complex topological relationships. This research introduces a query strategy to improve the query performance of geospatial knowledge base by creating spatial indexing on-the-fly to prune the search space for spatial queries and by parallelizing the spatial join computations within the queries. We focus on improving the performance of Geo-SPARQL queries on knowledge bases encoded in RDF. Our initial experiments show that the proposed strategy can greatly reduce the runtime costs of Geo-SPARQL query through on-the-fly spatial indexing and parallel execution. 相似文献
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GML空间数据查询与索引机制研究 总被引：9，自引：0，他引：9
由于传统GIS数据模型的差异，导致空间数据难以集成与共享。各GIS软件厂商及第三方软件厂商提出了利用空间数据转换的解决方案，但是它还是不能很好地解决空间数据集成与共享存在的问题。地理标记语言GML的出现，为GIS空间数据建模、集成与共享提供了统一的标准与框架。GML已经成为事实上的空间数据编码、传输、存储和发布的国际标准，大量GML格式的空间数据开始涌现。如何有效地存储管理GML空间数据，已经成为GIS研究的热点问题。本文结合XML数据库技术和传统的空间数据库技术，对GML空间数据的查询、索引进行了深入的研究。以XML标准查询语言XQuery为基础，提出了XQuery空间扩展的内容，开发了GML空间数据查询语言，实现了GML空间数据的本原查询；结合XML文档编码和传统的空间数据索引，提出了基于空间索引的GML一体化索引机制，并以R树索引为例，对一体化索引的查询处理性能进行了实验分析。实验结果表明，本文提出的基于空间索引的GML一体化索引机制是可行的、高效的。 相似文献
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广泛运用Web和分布式地理信息系统(WGIS/DGIS)有利于共享的空间数据库组织之间和用户通过互连网进行数据交换。不过,这些系统和应用软件的互操作性仍然是一个不能解决的问题,直到最近出版的地理标记语言(GML)标准的出现,这一问题才得到了解决。GML是一个新的实施规范并提供中立的框架为定义地理空间应用模式和对象的可扩展标记语言(XML)的文档。XML迅速成为一个事实上的标准电子数据交换之间的Web应用程序,然而,传统的数据库查询语言,在其目前的形式下并不适合直接查询和更新XML库。由W3C提出的XQuery查询语言为XML提供了强大的查询功能,但它缺乏支持空间查询,本文主要研究具有空间查询的语言GML-QL。 相似文献
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根据结构化查询语言ＳＱＬ的基本原理,设计了空间查询语言ＧｅｏＳＱＬ及其表达形式、界面设计和实现方法。ＧｅｏＳＱＬ的特色为：①采用子查询（ｓｕｂｑｕｅｒｙ） 重组ＦＲＯＭ 语句,使其符合一般空间操作的程序;②ＧｅｏＳＱＬ的界面设计融入了Ｉｃｏｎ、Ｌｉｓｔｂｏｘ 等可视化部件,易于查询文本的形成,且减少了语法错误。 相似文献
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Guan Jihong 《地球空间信息科学学报》2013,16(2):118-126
GML is becoming the de facto standard for electronic data exchange among the applications of Web and distributed geographic information systems. However, the conventional query languages (e.g. SQL and its extended versions) are not suitable for direct querying and updating of GML documents. Even the effective approaches working well with XML could not guarantee good results when applied to GML documents. Although XQuery is a powerful standard query language for XML, it is not proposed for queryings spatial features, which constitute the most important components in GML documents. We proposes GQL, a query language specification to support spatial queries over GML documents by extending XQuery. The data model, algebra, and formal semantics as well as various spatial functions and operations of GQL are presented in detail. 相似文献
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GQL： Extending XQuery to Query GML Documents 总被引：10，自引：2，他引：8
GUAN Jihong ZHU Fubao ZHOU Jiaogen NIU Liping 《地球空间信息科学学报》2006,9(2):118-126
IntroductionThe geography markup language (GML)[1]is anXML encoding in compliance with ISO 19118 forthe transport and storage of geographic informationmodel according to the conceptual modeling frame-work used in the ISO 19100 series and includingboth the… 相似文献
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基于自然语言的空间查询语言是空间数据库和智能GIS的重要研究领域。针对空间查询语言的特殊性就基于自然语言的空间查询语言的解译机制进行了细致的研究。在空间目标名称库、空间词汇库、空间查询句型模板库、空间语料库、查询结果模板库等空间知识库的支持下,介绍了如何用最大匹配分词技术对空间查询语句进行分词;说明了利用空间查询句型模板库中的句型对查询语句进行句法分析,最终解译出空间查询目标和相应空间操作的过程;详细阐述了如何进一步将这些空间目标和空间操作转换成中间空间查询语句(即扩展空间数据类型和空间函数的SQL),并由关系数据库执行查询;最后就如何选择文字或图形两种语言形式进行查询结果表示做了说明。 相似文献
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Because SQL for querying data from spatial databases is ineffective, the query based on natural or visual language becomes an attractive research field gradually. However, how to define and represent natural languages related to spatial data are still gigantic problems. Because existing models of direction relations can't describe by use of some common concepts. First of all, detailed direction relations are proposed to describe the directions related to the interior of spatial objects, such as “east part of a region”, “east boundary of a region”, and so on. Secondly, by integrating the detailed directions with exterior direction relations and topological relations, several NLSRs are defined, such as “a road goes across the east part of a lake”, “a river goes along the east boundary of a province”, etc. Finally, based on the NLSRs abovementioned, a natural spatial query language (NSQL) is formed to retrieve data from spatial databases. 相似文献
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受限自然语言查询在GIS中的应用 总被引：9，自引：0，他引：9
简单论述了空间信息系统的自然语言查询问题；在应用范围受限的条件下，提出了主要以自然语言中的关键词构造模式库来反映射查询语句的思想方法；建立了系统的体系结构，并对空间操作算子、空间查询语句、模式库的结构等关键问题进行了讨论。 相似文献
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DU Shihong WANG Qiao QIN Qiming 《地球空间信息科学学报》2006,9(1):55-64
Introduction Inmanyapplications(CADandgeographical informationsystem,GIS),dataaremanagedby spatialdatabases,whichstorepoint,line,region objectsandspatialrelationsbetweenthem.Spa tialrelations(topologicalrelations,directionre lationsandapproximatedistancer… 相似文献
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ABSTRACTUsing Artl@s as an example of a project that relies on volunteered geographic information (VGI), this article examines the specific challenges that exist, beyond those frequently discussed in general VGI systems (e.g., participants’ motivation and data quality control) in regard to sharing research data in humanities: (1) most data from the humanities is qualitative and collected from multiple data sources which are often inconsistent and unmappable; (2) data is usually interconnected with multiple relationships among different tables which creates challenges for both mapping and query functionality; (3) data is both geographical and historical. Consequently addresses that no longer exist have to be geolocated and visualized on historical basemaps and spaces must be represented diachronically; (4) the design of web map application needs to balance both sophisticated research requirements and a user-friendly interface; (5) finally contributors expect their data to be cited or acknowledged when used in other studies and users need metadata and citation information in order to reuse and repurpose datasets.In this article, we discuss how Artl@s, a project which developed a georeferenced historical database of exhibition catalogues, addresses these challenges. Artl@s provides a case study for VGI adoption by digital humanities scholars for research data sharing, as it offers features, such as flexible batch data contribution, interrelated spatial query, automatic geolocalization of historical addresses, and data citation mechanisms. 相似文献
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空间数据的社会、部门、企业的高级别应用的广泛性对日益海量化的空间数据共享提出了更高的要求。元数据是空间数据共享管理与交换的最佳解决方案。XML作为扩展性标记语言已经成为实现元数据描述的代语言。文中结合XML技术描述的元数据设计空间数据的共享管理平台,功能包含数据的检索、基于空间范围和关键字的查询、元数据查看、空间数据集的浏览等功能,实现空间数据的基本交换中心(站),为空间数据的高级别共享提供一种可行的实现途径。 相似文献