SVG与GML技术在地图服务系统中的应用     

吕凤涛 《测绘与空间地理信息》2011,34(5):152-155

针对WebGIS中网络矢量图形图像发布存在的问题,引入了GML与SVG技术,在此基础上提出并论证了基于SVG与GML的地图服务系统WebGIS的解决方案和应用模式,并详细分析了系统实现的体系结构和相关技术,着重论述了GML文档的解析、GML与SVG之间的转换方法、SVG交互功能的实现,最后给出了该系统的应用实例。  相似文献   

海量、异构矿业权核查数据的查询与优化     

陈苗  王永志  王慧 《地理信息世界》2011,(5):26-28,41

矿业权核查单个矿业权成果数据具有文件小、数量多、异构、多源等特点,对从海量、异构核查成果数据中快速查询并提取数据提出了挑战。本文探讨并建立了科学合理的数据模型,并提出综合应用表分区、存储过程、优化查询语句等数据库技术,有效提高了核查成果数据的访问与提取效率,为相同或类似应用需求提供了参考。  相似文献   

基于MapGIS图元参数检索开发与应用     

左仁广  夏庆霖  谭宁 《测绘科学》2007,32(4):86-87,37

根据GIS空间数据包含的信息:①空间定位数据;②属性数据;③空间图元信息。把数据检索进行重新分为空间检索、属性检索和空间图元参数检索等3类,并利用Visual basic6.0+Map GIS6.5二次开发函数库设计和开发出图元参数条件查询模块。该模块是空间检索和属性检索的有益的补充,且界面友好,可以有效地通过空间实体的图元参数进行数据检索,并应用于西藏冈底斯斑岩铜矿预测评价中,成功地通过图元参数检索提取了岩浆岩、断裂构造等有用信息。  相似文献   

地震救援现场灾情信息汇集和共享系统   总被引：1，自引：0，他引：1  

洪惠群  吴楠楠  郭进波  程志  林岩钊  黄玲珠 《华南地震》2013,33(2)

通过介绍地震救援现场灾情信息汇集和共享系统的工作原理、功能模块的设计过程、开发环境、系统的部署及实例,以及系统应用前景等,指出该系统能较好地实现地震现场灾情信息的快速收集、上报、关键信息特征的识别等功能,并能共享和充分利用现场信息.  相似文献   

XML Web Service‐based development model for Internet GIS applications     

Yoon‐Seop Chang 《International journal of geographical information science》2013,27(4):371-399

Most of the current Internet Geographic Information System (GIS) applications cannot be shared and are not interoperable because of their heterogeneous environments. With the growth of Internet GIS, many difficulties have occurred in integrating GIS components because of their diversity. The main objective of this study is to suggest a new development model for dynamic and interoperable Internet GIS applications. The model is based mainly on the dynamic integration of Internet GIS components by applying Extensible Markup Language (XML), XML Web Service, Geography Markup Language (GML), and Scalable Vector Graphics (SVG), etc. The relevant technologies of Internet GIS were reviewed thoroughly, and then a new model was designed. During the design of the new model, typical examples of GIS Web Service components were suggested, together with practical structures for applications using these components. Six examples of components and four types of applications were suggested, and they were experimentally implemented for model validation and improvement. The suggested model and components will enable easier and more rapid development of Internet GIS applications through the dynamic integration of distributed GIS components. Users will be able to avoid redundancy and consequently reduce both cost and time during each GIS project.  相似文献   

ST‐DMQL: A Semantic Trajectory Data Mining Query Language     

Vania Bogorny  Bart Kuijpers  Luis Otavio Alvares 《International journal of geographical information science》2013,27(10):1245-1276

Mobile devices are becoming very popular in recent years, and large amounts of trajectory data are generated by these devices. Trajectories left behind cars, humans, birds or other objects are a new kind of data which can be very useful in the decision making process in several application domains. These data, however, are normally available as sample points, and therefore have very little or no semantics. The analysis and knowledge extraction from trajectory sample points is very difficult from the user's point of view, and there is an emerging need for new data models, manipulation techniques, and tools to extract meaningful patterns from these data. In this paper we propose a new methodology for knowledge discovery from trajectories. We propose through a semantic trajectory data mining query language several functionalities to select, preprocess, and transform trajectory sample points into semantic trajectories at higher abstraction levels, in order to allow the user to extract meaningful, understandable, and useful patterns from trajectories. We claim that meaningful patterns can only be extracted from trajectories if the background geographical information is considered. Therefore we build the proposed methodology considering both moving object data and geographic information. The proposed language has been implemented in a toolkit in order to provide a first software prototype for trajectory knowledge discovery.  相似文献   

An analytic solution to the alibi query in the space–time prisms model for moving object data     

Bart Kuijpers  Rafael Grimson 《International journal of geographical information science》2013,27(2):293-322

Moving objects produce trajectories, which are stored in databases by means of finite samples of time-stamped locations. When speed limitations in these sample points are also known, space–time prisms (also called beads) (Pfoser and Jensen 1999 Pfoser, D. and Jensen, C.S. 1999. “Capturing the uncertainty of moving-object representations”. In Advances in spatial databases (SSD’99), Hong Kong, China, July 20–23, 1999, Vol. 1651, 111–132. Lecture notes in Computer Science.  [Google Scholar], Egenhofer 2003 Egenhofer, M. 2003. “Approximation of geopatial lifelines”. In SpadaGIS, workshop on spatial data and geographic information systsems, 4SpaDaGIS–Workshop on Spatial Data and Geographic Information Systems, Milano, Italy, March 2003. University of Genova.  [Google Scholar], Miller 2005 Miller, H. 2005. A measurement theory for time geography. Geographical Analysis, 37(1): 17–45. [Crossref], [Web of Science ®] , [Google Scholar]) can be used to model the uncertainty about an object's location in between sample points. In this setting, a query of particular interest that has been studied in the literature of geographic information systems (GIS) is the alibi query. This boolean query asks whether two moving objects could have physically met. This adds up to deciding whether the chains of space–time prisms (also called necklaces of beads) of these objects intersect. This problem can be reduced to deciding whether two space–time prisms intersect.

The alibi query can be seen as a constraint database query. In the constraint database model, spatial and spatiotemporal data are stored by boolean combinations of polynomial equalities and inequalities over the real numbers. The relational calculus augmented with polynomial constraints is the standard first-order query language for constraint databases and the alibi query can be expressed in it. The evaluation of the alibi query in the constraint database model relies on the elimination of a block of three exªistential quantifiers. Implementations of general purpose elimination algorithms, such as those provided by QEPCAD, Redlog, and Mathematica, are, for practical purposes, too slow in answering the alibi query for two specific space–time prisms. These software packages completely fail to answer the alibi query in the parametric case (i.e., when it is formulated in terms of parameters representing the sample points and speed constraints).

The main contribution of this article is an analytical solution to the parametric alibi query, which can be used to answer the alibi query on two specific space–time prisms in constant time (a matter of milliseconds in our implementation). It solves the alibi query for chains of space–time prisms in time proportional to the sum of the lengths of the chains. To back this claim up, we implemented our method in Mathematica alongside the traditional quantifier elimination method. The solutions we propose are based on the geometric argumentation and they illustrate the fact that some practical problems require creative solutions, where at least in theory, existing systems could provide a solution.  相似文献   

Mining query-driven contexts for geographic and temporal search     

Mariam Daoud 《International journal of geographical information science》2013,27(8):1530-1549

The explosive growth of geographic and temporal data has attracted much attention in information retrieval (IR) field. Since geographic and temporal information are often available in unstructured text, the IR task becomes a non-straightforward process. In this article, we propose a novel geo-temporal context mining approach and a geo-temporal ranking model for improving the search performance. Queries target implicitly ‘what’, ‘when’ and ‘where’ components. We model geographic and temporal query-dependent frequent patterns, called contexts. These contexts are derived based on extracting and ranking geographic and temporal entities found in pseudo-relevance feedback documents. Two methods are proposed for inferring the query-dependent contexts: (1) a frequency-based statistical approach and (2) a frequent pattern mining approach using a support threshold. The derived geographic and temporal query contexts are then exploited into a probabilistic ranking model. Finally, geographic, temporal and content-based scores are combined together for improving the geo-temporal search performance. We evaluate our approach on the New York Times news collection. The experimental results show that our proposed approach outperforms significantly a well-known baseline search, namely the probabilistic BM25 ranking model and state-of-the-art approaches in the field as well.  相似文献   

基于PostgreSQL的GML数据查询管理系统     

ZHANG Ai-guo  WU Qun-yong  XU Qi-feng 《测绘学院学报》2008,(5)

GML(Geography Markup Language,地理标记语言)用文本的形式来表示地理信息,提供了一种可扩展的、标准化的空间信息编码方式。目前GML空间数据的管理以文档存储管理方式为主,数据的查询更新效率低下,特别在文档较大时,对内存的要求也比较高。为此,这里设计和实现了一个基于PostgreSQL的GML数据管理系统,其中包括元数据查询、属性到图形的查询、空间信息到属性的查询和基于点位的查询,同时设计和实现了将查询到的WKT(the Well-Known Text)格式空间数据的可视化。  相似文献   

空间查询语言规范GML—QL的研究     

王飞 《国土资源信息化》2008,(4):31-35

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