A Service Oriented Geoprocessing System for Real‐Time Road Traffic Monitoring

The emergence of the Sensor Web has paved the way for a new set of innovative software applications that exploit the enhanced availability of real‐time information. This article describes one such application built from Sensor Web components that aggregates GPS track data from a fleet of vehicles to provide an overview of road traffic congestion at the city scale. The application embodies a Service Oriented Architecture; web service components are used to archive and pre‐process incoming sensor observations, to encapsulate a horizontally partitioned spatial database that performs geoprocessing, and to disseminate results to client applications. Our results confirm that floating car data can provide an accurate depiction of current road traffic conditions. The presented solution uses Open Geospatial Consortium web services where possible and serves to highlight the difficulties inherent in achieving horizontal database scalability in sensor based geoprocessing systems.     

支持主动注册和实时服务质量监测的地理信息目录服务

提出了一种结合爬行搜索技术、动态监测技术和带地理信息服务质量描述的地理信息目录服务机制,并以网络地图服务为例实现了原型系统。实验证明,本文提出的目录服务机制不但解决了传统目录服务存在的问题,而且能较好地满足用户在操作性、体验度和检索结果满意度方面的要求。     

主动式地理信息服务质量(QoAGIS)评估研究

设计主动式地理信息服务质量(quolily of active geospatial information service,QoAGIS)评估系统,阐述主动式地理信息服务的内涵及其逻辑结构,提出AGIS质量评估指标的概念,并对其中的本征质量指标与广义质量指标的定量化实现进行研究,给出综合评估指标.最后,通过实验表明QoAGIS评估系统的适应性和可靠性.

Abstract：

Currently, the passive aspects of geospatial information service (GIS) and the unpredictability of QoGIS are unable to meet the applications in some deeper fields. A new evaluation system of quality of active geospatial information service (QoAGIS) is presented. The connotation and logical structure of AGIS is analyzed, in which it advanced basic event and its expression, event operation's methods, the expression of complex event and the driven rules, the indices of QoAGIS evaluation are presented, in which the intrinsic quality index and the generalized quality index are researched on. Finally the compositive evaluation index is calculated. The QoAGIS evaluation system has been used in an application of AGIS, the experiment indicated its adaptation and reliability.     

Towards Real‐Time Geodemographics: Clustering Algorithm Performance for Large Multidimensional Spatial Databases

Geodemographic classifications provide discrete indicators of the social, economic and demographic characteristics of people living within small geographic areas. They have hitherto been regarded as products, which are the final “best” outcome that can be achieved using available data and algorithms. However, reduction in computational cost, increased network bandwidths and increasingly accessible spatial data infrastructures have together created the potential for the creation of classifications in near real time within distributed online environments. Yet paramount to the creation of truly real time geodemographic classifications is the ability for software to process and efficiency cluster large multidimensional spatial databases within a timescale that is consistent with online user interaction. To this end, this article evaluates the computational efficiency of a number of clustering algorithms with a view to creating geodemographic classifications “on the fly” at a range of different geographic scales.     

Geo‐Social Model: A Conceptual Framework for Real‐time Geocollaboration

Synchronous geocollaboration helps geographically dispersed people to work together in a shared geospatial environment. Its real‐time nature, multiple users' interaction and diversity of work context impose some special social, organizational and technological requirements, making the development of such real‐time geocollaboration systems a challenging task. A conceptual framework is therefore needed to specify and describe what synchronous geocollaboration is, considering its social, spatial and technical aspects. The geo‐social model presented in this article describes a conceptual framework for synchronous geocollaboration systems addressing the above aspects, identifies the core elements of the system and describes how these elements collaborate with each other. This model is presented using application‐level ontology and is then applied to a multi‐agent system based prototype in which multiple users can interact and negotiate in a shared 3D geospatial environment.     

互联网地图服务质量模型初探

随着地理空间技术和互联网技术的飞速发展,互联网地图服务也发展迅猛起来,它通过互联网向用户提供位置和导航等信息的服务。本文通过对现阶段国内互联网地图服务和应用情况的调查,从质量角度分析了影响互联网地图服务质量的因素,探讨了互联网地图服务质量模型的内容,为后期开展互联网地图服务质量评价体系研究奠定了基础。     

Exploring Real‐Time Geoprocessing in Cloud Computing: Navigation Services Case Study

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.     

Evaluation and Monitoring of Service Quality: Discussing Ways to Meet INSPIRE Requirements

Service oriented architectures (SOA) are widely used nowadays. As the name implies such architectures rely on services. Germany developed a marine‐specific service oriented data infrastructure (MDI‐DE – Marine Dateninfrastruktur Deutschland) from 2010 to 2013. The services in MDI‐DE can contribute to fulfilling reporting commitments for various European and national legislation. The services of MDI‐DE (just like other services affected, for instance, by INSPIRE) have to meet specific requirements regarding performance, availability and conformity (quality of service, QoS). Although SOA is an important field in scientific research there are very few publications and studies available on QoS, especially regarding INSPIRE requirements. The services of MDI‐DE were analyzed using various existing tools. Their usefulness to reflect where either the aspect's performance, availability or conformity needs improvement was partly verified. Due to varying results and the neglect of some services for various reasons it can be stated that the more tools are used, the more conclusive the outcome. Furthermore, service quality was not coherent when measured with different tools. This means that measuring QoS in terms of INSPIRE will be very difficult to do in the future and there is the danger that people will choose the tools with which their services perform best.     

基于Web目录服务的地学传感器观测服务注册和搜索

在分布式异构网络环境下,如何根据时间、空间和尺度等因子发现地学传感器和聚集传感器观测数据已成为自适应地球观测和空间信息服务中需要解决的问题.本文提出集成OGC的目录服务和传感器观测服务的地学传感器数据的访问方法和体系架构,包含分布式地学观测服务、基于ebRIM的目录服务、SOS注册与搜索服务中间件和地学传感器门户4个部件;深入探讨了观测数据注册的流程、观测能力注册的更新、目录服务中海量历史观测数据的管理和可视化搜索等实现技术;最后,基于传感器观测服务和目录服务标准,设计和实现了服务注册原型,并用E0-1的高光谱观测数据验证了服务原型的可行性,能够有效解决传感器观测服务、观测能力和观测结果的注册、管理和搜索.     

A GIS Toolbox for Measuring and Mapping Person‐Based Space‐Time Accessibility

This article presents a toolbox to compute and map person‐based accessibility indicators, based on classical time geography concepts. The intent is to provide GIS and urban planning practitioners with a user‐friendly and easily customizable tool. While it relies on well‐known concepts, the toolbox implements a major innovation in person‐based accessibility assessment by taking into account opening hours when measuring the accessibility of urban facilities. The toolbox can be downloaded from http://bit.ly/1h6yg5Z .     

地理国情监测成果质量评价关键技术与应用

针对地理国情监测成果质量检查验收中人工检查任务自动化程度不高的问题,重点研究了地理国情监测成果质量评价的关键技术;并对地理国情监测成果人工检查质量评定自动化、质量评价接口模型构建等内容进行了深入研究;最终实现了地理国情监测成果检查验收以及质量评价系统的设计与应用。     

基于WebGIS的饮用水水源地水质监测与评价系统设计

随着工业化进程加快,居民饮水安全受到的威胁日趋增多,因而以水源作为核心标准,加强对饮用水水源地水质的监测与评估对确保饮用水安全具有重要意义。本文利用GIS技术具有的空间特性,以城市饮用水的水源地为对象,结合单因子评价法和综合标识指数评价法建立水质评价模型,建立基于WebGIS的水质监测与评价系统,为水源地信息管理工作和保障城市饮用水安全提供技术支撑与数据依据。     

全站仪和激光投点仪放样钢管柱精度浅析

在地铁车站盖挖逆筑法施工中,钢管柱作为重要结构之一,具有定位精度要求高、施工操作难度大的特点[1]。本文从测量仪器和放样方法的误差来源入手,结合误差传播理论[2],对钢管柱平面放样精度公式进行推导,从而分析钢管柱平面位置定位精度是否满足相关要求,指导工程施工。     

深基坑变形监测方案设计与数据分析

黄河冲积平原地区水文地质复杂,基坑支护结构及监测技术方案设计是基坑工程的重要内容。本文以济南市武岳庙历史建筑保护工程基坑项目为例,研究了特殊水文地质条件下大型基坑支护结构设计及监测方案设计,并对基坑本身及周边环境进行实时监测。通过对监测数据的分析,得出了基坑本身及周边环境的沉降位移变化规律,验证了基坑支护结构设计的合理性和可靠性,对本地区的相似工程提供有益参考。     

一种支持数据发现及服务集成的遥感影像元数据模型设计

针对数据共享模式发展的要求,在分析遥感影像元数据模型研究现状的基础上,将传统静态的数据集元数据与动态的数据服务元数据相结合,提出了一种适用于计算机动态发现数据并集成数据服务的遥感影像元数据模型.基于该模型进行了"Machine to Machine"模式的遥感影像数据共享实验,验证了模型的合理性和有效性.     

An Evaluation of Internet Versus Paper‐based Methods for Public Participation Geographic Information Systems (PPGIS)

Public participation geographic information systems (PPGIS) are an increasingly important tool for collecting spatial information about the social attributes of place. The availability of Internet‐based options for implementing PPGIS presents new opportunities for increased efficiency and new modes of access. Here we used a mixed‐mode approach to evaluate paper versus Internet mapping methods for the same PPGIS survey in Wyoming. We compared participant characteristics, mapping participation, and the spatial distribution of mapped attributes between participants who responded to the paper versus Internet option. The response rate for those who completed the paper version of the survey was nearly 2.5 times the response rate of the Internet version. Paper participants also mapped significantly more places than did Internet participants (43 vs. 18). Internet participants tended to be younger, more likely to have a college degree, and had lived in the region for less time than paper participants. For all but one attribute there was no difference in the spatial distribution of places mapped between Internet and paper methods. Using a paper‐based PPGIS survey resulted in a higher response rate, reduced participant bias, and greater mapping participation. However, survey mode did not influence the spatial distribution of the PPGIS data.     

Collaborative Web‐GIS Design: A Case Study for Road Risk Analysis and Monitoring

This article presents a methodology for designing a WebGIS framework intended for automatically analyzing spatial data and updating statistics of interest with new information inserted daily by multiple users via a Web portal. A practical example is used on vehicle accident data for assessing risk in specific road segments. Two main blocks integrated together will be described: the collaborative block and the data‐analysis block. The former gives end‐users computer‐aided tools to view, insert, modify and manage data related to accidents and traffic monitoring sensors, whereas the latter is developed to automatically analyze the accident data coming from user's collaboration. Because different agencies can survey accident sites, a collaborative environment is necessary – and a Web‐based solution is ideal – for permitting multi‐user access and data insertion. A centralized approach to process the data in real time is described in all its components. Server‐side Structured Query Language functions optimize performance by using dedicated libraries for spatial processing and re‐structuring the attributes associated with elements which are consequently re‐classified for correct color‐scaling. The end‐product is a system that provides a seamless integration of front‐end tools for user collaboration and back‐end tools to update accident risk statistics in real time and provide them to stakeholders.     

浅谈地理国情监测成果质量检验与评定

简述了地理国情监测成果质量检验与评定方法,明确了地理国情监测成果抽样过程、质量元素、质量子元素、检查项,给出了地表覆盖类、地理国情类地理国情监测成果样本质量评定指标和批质量判定方法。     

基于WebGIS的城市饮用水源地水质监测评价系统的实现

介绍了以城市饮用水的水质监测与评价为目标,Flex Viewer为框架,综合运用WebGIS,Flex, WebService,水质评价模型等技术进行开发的城市饮用水水源地水质监测评价系统。该系统具有地图服务、水质监测、水质评价、统计等功能,监测饮用水源地水质及其变化状况,进行水质评价生成专题图,方便专业人员和社会公众对水质监测成果的直观了解。