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Bastian Baranski Theodor Foerster Bastian Schäffer Kristof Lange 《Transactions in GIS》2011,15(Z1):125-142
A lot of effort has been invested in Spatial Data Infrastructures (SDIs) during the last decade regarding interoperable standards for services and data. But still the scalability and performance of SDI services is reported to be crucial especially if they are accessed concurrently by a high number of users. Furthermore, laws and provisions such as the INSPIRE directive specify challenging requirements regarding the performance, availability and scalability of SDI services. This article presents a Hybrid Cloud architecture for matching INSPIRE‐related Quality of Service (QoS) requirements, without investing in rarely used hardware in advance, by occupying external third‐party resources on a pay‐as‐you‐go basis. The presented Hybrid Cloud is a composition of a local IT‐infrastructure (Private Cloud) and the computational resources of third‐party vendors (Public Cloud). The local infrastructure is laid out to handle the average main load of a service and in lasting peak times additional resources of external providers are allocated and integrated on demand into the local infrastructure to provide sufficient service quality automatically. A proof‐of‐concept implementation of the proposed Hybrid Cloud approach is evaluated and benchmarked with respect to INSPIRE‐related QoS requirements. 相似文献
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Geographic information has a great potential to be re-used when supported by mechanisms for its discovery. Above all, the quality of a catalogue service is the key feature supporting users in the discovery process. So far, there have been in existence various methodologies dealing with the normalized evaluation of quality with respect to catalogue services. Their biggest weakness seems to be in the depth of quality testing, i.e. some influences are beyond the scope of evaluation of these methodologies with respect to quality in catalogue services. In this study, the quality of 45 catalogue services across Europe was verified with the proposed normalized evaluation methodology originating from documents within the INfrastruture for SPatial InfoRmation in Europe (INSPIRE) framework. This paper discusses the (statistical) influence of factors that may significantly change the results of catalogue service testing. The proposals for improving the existing INSPIRE normalized evaluation procedure are applicable for any spatial data infrastructure and/or Digital Earth component using the Open Geospatial Consortium Catalogue Service for the Web as a basis. 相似文献
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Dynamic chaining of geographic information services (geo-services) is gaining popularity as a new paradigm for evolving flexible geo-information systems and for providing on-demand access to geo-information. In dynamic chaining, disparate geo-services are discovered and composed at run time to yield more elaborate functionality and create value-added geo-information. Common approaches to service chaining discover and compose disparate geo-services based on the functional capability of individual geo-services. The primary concern of common approaches is thus the emergent behavior of the resulting composite geo-service. However, as geo-services become mundane and take on a greater and more strategic role in mission critical processes, deliverable quality of service (QoS) becomes an important concern. QoS concerns operational characteristics of a service that determine its utility in an application context. To address pertinent QoS requirements, a new approach to service chaining becomes necessary. In this paper we propose a QoS-aware chaining approach in which geo-services are discovered, composed and executed considering both functional and QoS requirements. We prescribe a QoS management framework that defines fundamental principles, concepts and mechanisms which can be applied to evolve an effective distributed computing platform for QoS-aware chaining of geo-services – the so-called geo-service infrastructure. The paper also defines an extensible QoS model for services delivered by dynamic compositions of geo-services. The process of orthophoto generation is used to demonstrate the applicability of the prescribed framework to service-oriented geographic information processing. 相似文献
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Today, many real‐time geospatial applications (e.g. navigation and location‐based services) involve data‐ and/or compute‐intensive geoprocessing tasks where performance is of great importance. Cloud computing, a promising platform with a large pool of storage and computing resources, could be a practical solution for hosting vast amounts of data and for real‐time processing. In this article, we explored the feasibility of using Google App Engine (GAE), the cloud computing technology by Google, for a module in navigation services, called Integrated GNSS (iGNSS) QoS prediction. The objective of this module is to predict quality of iGNSS positioning solutions for prospective routes in advance. iGNSS QoS prediction involves the real‐time computation of large Triangulated Irregular Networks (TINs) generated from LiDAR data. We experimented with the Google App Engine (GAE) and stored a large TIN for two geoprocessing operations (proximity and bounding box) required for iGNSS QoS prediction. The experimental results revealed that while cloud computing can potentially be used for development and deployment of data‐ and/or compute‐intensive geospatial applications, current cloud platforms require improvements and special tools for handling real‐time geoprocessing, such as iGNSS QoS prediction, efficiently. The article also provides a set of general guidelines for future development of real‐time geoprocessing in clouds. 相似文献
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Designing Service Architectures for Distributed Geoprocessing: Challenges and Future Directions 总被引：5，自引：0，他引：5
Anders Friis-Christensen Nicole Ostländer Michael Lutz Lars Bernard 《Transactions in GIS》2007,11(6):799-818
In this paper we study the feasibility of using services offered by a Spatial Data Infrastructure as a basis for distributed service oriented geoprocessing. By developing a prototype we demonstrate that a Spatial Data Infrastructure facilitates rapid development of applications that solve typical problems for an existing risk management application. The prototype provides users with a distributed application that enables the assessment of fire damage areas based on land cover data in a given area. The services involved in the application include: Web Feature Services, Web Map Services, a Gazetteer Service, a Catalogue Service, and Geoprocessing Services. We present the architecture of the application and describe details about implementation‐specific issues. We conclude that current OGC specifications provide a sound basis for developing service oriented architectures for geographic applications; however, in particular for geoprocessing applications, we question the feasibility of the use of Web Feature Services as data sources for larger amounts of data and call for further research in this direction. 相似文献
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针对地理信息服务质量与普通Web服务质量的差异,将QoS引入地理信息服务领域,并进行合适扩展,建立通用QoGIS模型。利用此模型以及不同用户的需求提出地理信息服务选择的实现过程。最后通过实验验证模型的有效性。 相似文献
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依据新型基础测绘的服务要求,制定了科学合理的图库一体化的生产路线,总结了注意事项,研究开发了图库一体化的质检工具,提高了基础测绘的生产效率和质量,为新型基础测绘“按需服务”奠定了基础。 相似文献
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论述了面向服务架构下的主动地理信息服务模型,由于主动型的地理信息服务在用户发现、定制和运行方面都能够满足用户的需求服务,从而改变了当前用户只能被动地使用现有服务的应用模式,以应对信息化需求的不断发展和变化。并将模型中的关键技术地理信息服务发现与组合的算法问题规划为离散、有限的数据结构上的最优化问题。在分析服务质量(QoS)属性的基础上,提出基于自动修正判断矩阵的QoS最优选择算法,旨在得到一个解决地理信息服务组合选择的近似最优解决方案,以达到快速选择最优服务的目的。实验结果表明,该方法能有效提高主动地理信息服务的执行效率。 相似文献
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北斗三号导航定位技术体制与服务性能 总被引：2，自引：1，他引：1
介绍了北斗三号系统的星座设计、服务类型、导航信号体制、时空基准以及轨道确定与时间同步机制等技术体制，分析提出了评估北斗三号导航定位服务性能的指标体系，指标涵盖时空基准、空间信号质量、空间信号精度和服务性能4个方面，综合利用全球数据资源对北斗三号基本系统的导航定位服务性能进行了评估。结果显示，各信号分量有效功率比偏差优于0.25 dB，S曲线过零点偏差（SCB）优于0.3 ns，满足设计要求；北斗三号基本系统当前全球位置精度因子（PDOP）可用性优于85.0%，空间信号测距误差0.48 m（RMS），空间信号连续性99.99%，空间信号可用性99.78%，UTC偏差误差优于19.1 ns（95%），均满足系统服务性能规范承诺的指标。相对于北斗二号而言，北斗三号在覆盖能力、空间信号精度、空间信号可用性、空间信号连续性等方面均有显著提升。 相似文献
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为了解决长久以来服务发现的难题,提出了基于语义的地理信息Web服务发现机制.针对地理信息Web服务语义缺乏的问题,在服务的描述和匹配中引入语义的概念;针对地理信息Web服务质量(QoS)支持不足的问题,在服务的匹配中引入QoS的约束;针对Web服务匹配算法缺乏灵活性的问题,提出多级服务匹配的思想;针对粗糙目录分类(或无... 相似文献
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现有的空间信息共享平台框架及开发模式较难灵活地完成地理信息服务和应用系统多层次的融合、空间信息资源整合及空间信息的共享等问题。本文通过一种基于SOA网格管理模型(service-oriented architecture,SOA)的空间信息共享平台设计框架,结合空间信息多级网格和SOA服务体系框架的优点解决了在广域网络环境下整合空间信息资源从而有利于空间信息共享的问题,并通过多级地图缓存服务,即利用对各种比例尺的地图数据在计算机内存中的临时存储,来提高用户在编辑、特征渲染和标注等操作的响应速度的技术来解决空间数据的传输和显示等问题。 相似文献
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《International Journal of Digital Earth》2013,6(5):417-438
Abstract The HUMBOLDT project has the aim of implementing a Framework for harmonisation of data and services in the geoinformation domain, under the Infrastructure for Spatial Information in Europe (INSPIRE) Directive and in the context of the Global Monitoring for Environment and Security (GMES) Initiative. The two-pronged approach of HUMBOLDT comprises a technical side of software framework development and an application side of scenario testing and validation. Among the HUMBOLDT Application Scenarios designed to demonstrate the capabilities of the Framework there is the one covering Protected Areas themes and use cases. It aims to transform geoinformation, managed by park authorities, into a seamless flow that combines multiple information sources from different governance levels (European, national, regional), and exploits this newly combined information for the purposes of planning, management and tourism promotion. The Scenario constitutes a step further towards the integration of monitoring systems envisaged in the view of Digital Earth. Protected Areas Scenario creates an examples of the use of the HUMBOLDT tools in Desktop and Web GIS environment, together with setting up a server environment exploiting HUMBOLDT harmonisation framework as taking into account user requirements and needs and providing benefits for making the road to ESDI establishment easier. 相似文献
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Hassan A. Karimi Monir H. Sharker Duangduen Roongpiboonsopit 《Transactions in GIS》2011,15(6):869-886
Today, many services that can geocode addresses are available to domain scientists and researchers, software developers, and end‐users. For a number of reasons, including quality of reference database and interpolation technique, a given address geocoded by different services does not often result in the same location. Considering that there are many widely available and accessible geocoding services and that each geocoding service may utilize a different reference database and interpolation technique, selecting a suitable geocoding service that meets the requirements of any application or user is a challenging task. This is especially true for online geocoding services which are often used as black boxes and do not provide knowledge about the reference databases and the interpolation techniques they employ. In this article, we present a geocoding recommender algorithm that can recommend optimal online geocoding services by realizing the characteristics (positional accuracy and match rate) of the services and preferences of the user and/or their application. The algorithm is simulated and analyzed using six popular online geocoding services for different address types (agricultural, commercial, industrial, residential) and preferences (match rate, positional accuracy). 相似文献
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随着空间信息技术和网络技术的发展,地理信息系统（GIS）也在不断地从2维世界走向3维世界,从GIS应用走向GIS服务。在此基础上,本文提出了3DGIS Web服务,并设计了基于SOA的3DGIS Web服务多层体系结构、3DGIS Web服务的数据源和API框架,论述了3DGIS Web服务和现有的2维GIS Web服务集成需要解决的关键技术问题。 相似文献
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针对常用的空间信息处理服务,分析了相关领域服务组合方法的优缺点,结合服务资源本身及神经网络的智能性特点,提出了基于神经网络概念的服务智能组合方法,以尽可能准确高效地实现服务组合的自动化该方法采用面向特殊服务扩展本体表达模型,结合语义描述,利用神经网络的突触原理完成核心服务的查找,最后通过集成索引函数实现服务的串接实验结果表明,在保证满足应用需求的情况下,此方法缓解了非专业用户的服务再组合障碍,提高了计算效率。 相似文献