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ABSTRACTOn nautical charts, undersea features are portrayed by sets of soundings (depth points) and isobaths (depth contours) from which map readers can interpret undersea features. Different techniques were developed for automatic sounding selection and isobath generalization. These methods are mainly used to generate a new chart from the bathymetric database or from a larger scale chart through selection and simplification. However, a part of the process consists in selecting and emphasizing undersea features formed by groups of soundings and isobaths on the chart according to their relevance to maritime navigation. Hence, automation of the process requires classification of features and their generalization through the application of a set of operators according not only to geometric constraints but also to their meaning.The objective of this work is to conceive a multi-agent system (MAS) for nautical chart generalization that is driven by the knowledge on the generalization process and the undersea features and their relationships. First, this work provides a feature-centered ontology modeling of the generalization process. Then, the MAS structure is introduced where agents access cartographic knowledge stored in the ontology. The MAS makes use of measure algorithms to evaluate constraint violations on the chart in order to decide which generalization operators to apply. The whole model has been implemented to provide generalization plans on a real case study. 相似文献
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D. Van de Vlag B. Vasseur A. Stein R. Jeansoulin 《International journal of geographical information science》2013,27(10):1057-1072
An ontological approach in GIS serves as a framework for the conceptualization of processes in the real world. In this paper, we examine an application in coastal change in the Netherlands, whereby beaches are subject to artificial nourishment to offset the effect of severe erosion. The use of ontologies helps to define two scenarios: SI determined by the regulations from the Ministry for Public Works; SII grounded on the abilities from an existing spatial dataset. A comparison between SI and SII shows that 72.8% of the objects suitable and unsuitable for nourishment are correctly classified. A higher overlap is found in areas where actual beach nourishments were carried out. Inaccuracies in attributes influence the determination of the objects. A sensitivity analysis applied to altitude illustrates a significant increase of objects suitable for nourishment for both scenarios, when altitude is decreased within the lower limit of the root mean square error for the 95% confidence interval. Moreover, the sensitivity of altitude shows that artificial boundaries for beach nourishment objects are not reasonable and consequently should be treated as vague objects. 相似文献
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Emily White Kathleen Stewart 《International journal of geographical information science》2013,27(6):1007-1022
When separation between geospatial features is desired, an obstacle or barrier is used to maintain distance between the features. Barriers are used in a wide variety of domains, such as hazards, transportation, and public safety. Floodwalls, for example, prevent flooding rivers or lakes from inundating buildings. This work presents an ontology design pattern for barriers and barring events useful for GIS. In this ontology design pattern, active features (e.g., the water-body that is causing flooding) and target features (e.g., buildings requiring flood protection) are defined. Along with these key features, the ontology design pattern also captures certain barring events. These are the dynamics that arise from the placement of barriers and include Blocking, Enclosing, KeepingIn and KeepingOut, involving interactions among barriers, and active and target features. The set of classes that model these features and events as well as the relations between them are presented and formalized. This design pattern is ready for integration in a GIS to allow queries on barriers and barring events that do not currently have explicit support in most GIS. 相似文献
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地理空间数据语义异构是实现数据关联、数据智能推荐和精确发现的主要瓶颈。地理空间数据本体被认为是解决地理空间数据语义异构的有效方法。形态特征是地理空间数据(除时空、要素内容外)的重要特征,是地理空间数据本体的重要研究内容。本文首先在系统分析地理空间数据形态特征的基础上,提出地理空间数据形态特征的概念体系。然后,建立地理空间数据形态本体模型,提出形态信息的本体表示方法,并构建地理空间数据形态本体。最后,基于形态本体的本体库,利用Jena本体推理技术,开发地理空间数据语义检索原型系统,并将形态本体应用于国家地球系统科学数据共享平台的元数据检索中。实验结果表明,地理空间数据形态本体可以有效地解决数据形态特征的语义异构,提高数据发现的查全率和查准率。本文的研究方法和成果对解决其他领域数据的语义异构,有重要的参考意义。 相似文献
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整合GIS的生态环境建模与EDSS研究进展 总被引：1，自引：0，他引：1
围绕生态环境的空间问题建模及模型集成机制,综合评述了环境建模及其应用软件的研究现状和发展趋势,对比分析了生态环境模型与GIS集成的多种方式,重点讨论了当前环境决策支持系统的开发策略和研究热点,并结合本体技术和语义网服务展望了未来环境决策支持系统解决方案的特征。 相似文献
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地理本体与空间信息多级网格 总被引：12，自引：0，他引：12
为解决空间数据分布异构的问题,根据地理本体与地理网格的特点,提出一种将地理本体映射到地理网格的新方法,并用该方法构造一种基于本体的空间信息网格系统。该系统通过描述空间信息的语义内涵的本体系统对空间信息数据进行索引和组织,并以地理网格为其存储和管理单元,可以有效地解决在广域网络环境下的空间信息资源整合的问题,促进空间信息共享与利用的研究。 相似文献
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为了实现基于多源WFS服务要素层次的语义检索,提出了一个要素本体的五元模型。在此框架下,研究了要素本体的自动构建方法,形式化定义了要素的空间关系,并扩展了逻辑关系以及空间关系的推理规则来实现要素层次的联合推理检索,并给出了联合规则推理的要素语义检索算法。实例证明,本文方法对多源WFS的语义查询具有实际的可行性,为多源WFS服务要素的语义检索提供了一个新的方法。 相似文献
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