首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献，搜索用时 15 毫秒
1.
Quality Assessment of the French OpenStreetMap Dataset   总被引：9，自引：1，他引：8  
The concept of Volunteered Geographic Information (VGI) has recently emerged from the new Web 2.0 technologies. The OpenStreetMap project is currently the most significant example of a system based on VGI. It aims at producing free vector geographic databases using contributions from Internet users. Spatial data quality becomes a key consideration in this context of freely downloadable geographic databases. This article studies the quality of French OpenStreetMap data. It extends the work of Haklay to France, provides a larger set of spatial data quality element assessments (i.e. geometric, attribute, semantic and temporal accuracy, logical consistency, completeness, lineage, and usage), and uses different methods of quality control. The outcome of the study raises questions such as the heterogeneity of processes, scales of production, and the compliance to standardized and accepted specifications. In order to improve data quality, a balance has to be struck between the contributors' freedom and their respect of specifications. The development of appropriate solutions to provide this balance is an important research issue in the domain of user‐generated content.  相似文献   

2.
  相似文献   

3.
The concept of Volunteered Geographic Information (VGI) has progressed from being an exotic prospect to making a profound impact on GIScience and geography in general, as initially anticipated. However, while massive and manifold data is continuously produced voluntarily and applications are built for information and knowledge extraction, the initially introduced concept of VGI lacks certain methodological perspectives in this regard which have not been fully elaborated. In this article we highlight and discuss an important gap in this concept, i.e. the lack of formal acknowledgment of temporal aspects. By coining the proposed advanced framework ‘Volunteered Geo‐Dynamic Information’ (VGDI), we attempt to lay the ground for full conceptual and applied spatio‐temporal integration. To illustrate that integrative approach of VGDI and its benefits, we describe the potential impact on the field of dynamic population distribution modeling. While traditional approaches in that domain rely on survey‐based data and statistics as well as static geographic information, the use of VGDI enables a dynamic setup. Foursquare venue and user check‐in data are presented for a test site in Lisbon, Portugal. Two core modules of spatio‐temporal population assessment are thereby addressed, namely time use profiling and target zone characterization, motivated by the potential integration in existing population dynamics frameworks such as the DynaPop model.  相似文献   

4.
浅论自发地理信息的数据管理   总被引：5，自引：0，他引：5  
分析了自发地理信息(volunteered geographic information,VGI)数据的来源、分类、特点与管理要求,探讨了VGI数据清理与质量控制,研究了以高效处理绘图查询与数据更新为目标的VGI图形数据管理问题,提出了动态线综合二叉树与缩放四叉树的设计思想,以解决VGI图形数据管理中的难点问题。  相似文献   

5.
Initiatives that rely upon the contributions of volunteers to reach a specific goal are growing more and more with the success of Web 2.0–interactive applications. Also scientific projects are testing and exploiting volunteers' collaboration, but the quality of information obtained with this approach is often puzzling. This paper offers a rich overview of many scientific projects where geographic contributions are committed to volunteers, to the aim of defining strategies to improve information quality. By describing real examples of Volunteer Geographic Information (VGI), the contribution establishes a categorization based on the characteristics of the information, tasks, and scopes of the projects. After a discussion on the relationships of categories and VGI quality, the paper analyses techniques to improve the quality of volunteered information according to the moment of its assessment (i.e., ex ante, ex post, or both with respect to information creation). The paper outlines the main limitations of the different approaches and indicates some guidelines for future developments.  相似文献   

6.
Residential locations play an important role in understanding the form and function of urban systems. However, it is impossible to release this detailed information publicly, due to the issue of privacy. The rapid development of location‐based services and the prevalence of global position system (GPS)‐equipped devices provide an unprecedented opportunity to infer residential locations from user‐generated geographic information. This article compares different approaches for predicting Twitter users' home locations at a precise point level based on temporal and spatial features extracted from geo‐tagged tweets. Among the three deterministic approaches, the one that estimates the home location for each user by finding the weighted most frequently visited (WMFV) cluster of that user always provides the best performance when compared with the other two methods. The results of a fourth approach, based on the support vector machine (SVM), are severely affected by the threshold value for a cluster to be identified as the home.  相似文献   

7.
  相似文献   

8.
Studies on volunteered geographic information (VGI) have focused on examining its validity to reveal geographic phenomena in relatively recent periods. Empirical evaluation of the validity of VGI to reveal geographic phenomena in historical periods (e.g., decades ago) is lacking, although such evaluation is desirable for assessing the possibility of broadening the temporal scope of VGI applications. This article presents an evaluation of the validity of VGI to reveal historical geographic phenomena through a citizen data‐based habitat suitability mapping case study. Citizen data (i.e., sightings) of the black‐and‐white snub‐nosed monkey (Rhinopithecus bieti) were elicited from local residents through three‐dimensional (3D) geovisualization interviews in Yunnan, China. The validity of the elicited sightings to reveal the historical R. bieti distribution was evaluated through habitat suitability mapping using the citizen data in historical periods. The results of controlled experiments demonstrated that suitability maps predicted using the historical citizen data had a consistent spatial pattern (correlation above 0.60) that reflects the R. bieti distribution (Boyce index around 0.90) in areas free of significant environmental change across historical periods. This in turn suggests that citizen data have validity for mapping historical geographic phenomena. It provides supporting empirical evidence for potentially broadening the temporal scope of VGI applications.  相似文献   

9.
The emergence of volunteered geographic information (VGI) during the past decade has fueled a wide range of research and applications. The assessment of VGI quality and fitness‐of‐use is still a challenge because of the non‐standardized and crowdsourced data collection process, as well as the unknown skill and motivation of the contributors. However, the frequent approach of assessing VGI quality against external data sources using ISO quality standard measures is problematic because of a frequent lack of available external (reference) data, and because for certain types of features, VGI might be more up‐to‐date than the reference data. Therefore, a VGI‐intrinsic measure of quality is highly desirable. This study proposes such an intrinsic measure of quality by developing the concept of aggregated expertise based on the characteristics of a feature's contributors. The article further operationalizes this concept and examines its feasibility through a case study using OpenStreetMap (OSM). The comparison of model OSM feature quality with information from a field survey demonstrates the successful implementation of this novel approach.  相似文献   

10.
周边区域地理信息的获取是我国地缘环境研究中的一个难题,志愿者地理信息(volunteered geographic information,VGI)的兴起为解决该难题提供了一个可行的方法。在目前一系列的VGI项目中,OpenStreetMap(OSM)是比较领先的应用,但OSM数据模型不同于我国周边应用的专业矢量数据模型,因此,利用OSM数据时首先需要对其进行模型转换。有鉴于此,本文提出了一种基于规则的OSM数据到专业应用矢量数据模型转换方法。该方法首先利用OSM定义的几何类型与地物属性作为分类依据,建立了模型转换基本规则库;对于志愿者根据自己的理解自行标注未包含在基本规则库中的目标采用人机交互方式进行模型转换,并在此过程中不断完善规则库,利用越南与巴基斯坦数据进行实验,最终形成了包括2 344条转换规则的模型转换规则库,为OSM数据模型到专业应用矢量数据模型的转换提供了一条可行途径。  相似文献   

11.
Using volunteered geographic information (VGI) as a cost‐saving environmental monitoring and public participation mechanism has been thought to be a proof of concept to assist environmental decision‐making with insufficient managerial resources. However, research literature also often found institutional resistance when implementing VGI as part of the decision‐making process. This research develops a conceptual framework as the foundation to conduct a cross‐case comparison for four empirical cases in recreation and invasive species monitoring, but general enough for other such case comparisons. The VGI Reporting Assessment Framework (VGI‐RAF) adopted aspects of the Decision Situation Assessment (DSA) framework as the foundation to address institutional flexibility, stakeholder dynamics, and technical considerations. Using a cross‐case comparison can accumulate deep observations from cases and increase validity of insights through comparing processes. Results show that eight aspects of the VGI‐RAF reveal the suitability of embedding voluntary information within existing institutional decision‐making processes. VGI‐RAF depicts considerations for: (1) existing participation arrangements, (2) institutional arrangements, (3) managers’ needs and stakeholder expectation, and (4) interaction mechanism and technical needs. The cross‐comparison results indicate that a public participation mechanism should be accompanied by VGI development to increase effectiveness. Institutional arrangements should match local government's information needs with participants’ expectations. Knowledge gaps between institutional information needs and volunteer knowledge should be filled through technology enhancements. For ease of implementation and to promote long‐term success, we recommend that volunteered information be connected with existing communication channels to minimize changes to existing information systems.  相似文献   

12.
东海宇 《北京测绘》2012,(4):103-104
地理信息数据库经历了从CAD、Coverage到Geodatabase的过程,Geodatabase定义了地理信息的普通模型,可定义并用于不同用户或专业应用模型,为各种用户数据模型的定义提供强大的平台,支持面向对象的矢量数据。  相似文献   

13.
In this article, we present a fuzzy model for intrinsic quality assessment of Volunteered Geographic Information (VGI) on species occurrences obtained by Citizen Science (CS) biodiversity monitoring programs. The proposed VGI quality assurance approach evaluates the thematic and positional quality of the crowdsourced biodiversity observation in terms of the trustworthiness of the observation by combining three indicators of consistency with habitat, consistency with surroundings, and reputation of contributor, that characterize the geographical and social aspects of trust in VGI. To evaluate the performance and usability of the proposed approach for evaluating the trustworthiness of crowdsourced observations and detecting thematic and positional errors in crowdsourced observations, the developed approach was applied to the crowdsourced observations on Acer macrophyllum collected through the CS biodiversity monitoring projects of E-Flora BC and iNaturalist. The result of a conformity test at the optimal acceptance threshold (sensitivity = 0.99, specificity = 0.8, and Cohen’s kappa = 0.79), the achieved area under the curve (AUC) value (AUC = 0.98), and the results of the complementary investigation on the predictions of the proposed model indicated that the proposed fuzzy trust model exhibited promising predictive performance and was able to flag the majority of attribute and positional errors in the crowdsourced biodiversity observations.  相似文献   

14.
范红超  孔格菲  杨岸然 《测绘学报》2022,51(7):1653-1668
众源地理信息作为新型地理信息模式,是指由互联网用户借助交互式平台,通过直接上传传感器数据或提供数字化劳动而贡献的地理信息数据。近20年来,众源地理信息热度上升,并受到越来越多研究者的关注,正在逐渐成为一种重要的地理信息数据来源。本文对近十几年来关于众源地理信息的中文和英文文献进行了系统性的分析与研究,力图展现出众源地理信息研究的发展现状,同时以这些研究发现的规律为基础,结合当前的国际形势,探讨了众源地理信息的发展机遇与挑战,同时对发展自主众源地理信息给出了建议。  相似文献   

15.
Web网站中存在种类繁多的地理信息,但由于格式、用户权限等限制,用户多数只能浏览,并不能直接利用。为有效地利用网站中大量的地理信息数据,本文介绍几种自动抓取Web网站中地理信息,并将地理信息转化成可直接利用的空间数据的方法,以实现批量操作空间数据。  相似文献   

16.
自发地理信息(VGI)是一种新兴的地理数据采集方式,具有数据更新快、细节丰富、覆盖范围广等优势。利用VGI数据可以对道路网实现快速更新;但是由于VGI数据是非专业自发共享的,且数据采集时多使用非专业设备,所以存在数据质量不高的问题。大量VGI数据对同一地理要素的重复采集与融合处理则可改善数据的质量,文中以多人采集的道路网数据为例,结合矢量要素的匹配与融合理论,设计一种适用于道路网VGI数据的匹配与融合算法。首先在路段结点处建立缓冲区进行结点匹配,再根据路段距离相似度进行路段匹配,最后再利用Delaunay三角剖分融合算法对匹配后的同名路段进行融合。将匹配融合后的道路网与原始道路网VGI数据及Google影像图叠加对比分析,结果表明利用本文算法可有效地实现道路网VGI数据的匹配与融合。  相似文献   

17.
在Web 2.0的驱动下,伴随着UGC(User Generated Content)的爆炸式增长,出现了一种新形式的地理信息——志愿者地理信息(Volunteered Geography Information,以下简称VGI)。其中点评类VGI提供了传统地理信息难以提供的商户环境、服务质量等信息,从而增强了地理信息对环境的表达能力,为消费者决策提供了重要参考。通过对大众点评网的点评信息进行分析,发现商户实体对点评信息的空间分布起着很大的制约作用,使得点评信息延续了商户不均衡的分布态势。但这种制约并不起决定性作用,点评信息仍然表现出一些区别于商户分布格局的特点。随后通过对不同价位餐馆的点评量进行分析,发现消费者更倾向对平均价格较高的餐馆进行点评,从而可能使得部分低价位的餐馆面临信息缺失的危机。  相似文献   

18.
地理信息数据处于动态变化之中,传统的地理信息数据采集方式由少量专业单位组织,耗时长、效率低,难以满足数据的快速采集和及时更新要求。本文介绍了基于Web平台的志愿者地名地址数据采集方案,由志愿者提交地名地址数据的网站和数据库,利用互联网的高效、开放、共享等特点,实现对海量地理数据的快速采集和更新,是一种高效低廉的地理信息数据采集方式,每个用户既是地理信息的使用者,也是地理信息的提供者,可长期低成本维持地理信息数据的现势性。  相似文献   

19.
Volunteered geographic information (VGI) has been studied extensively within various contexts, however, generally focusing on isolated aspects of data. Therefore, we still need to advance the structured knowledge of the mechanisms that affect and support its creation. This article aims to contribute to the integrated study of VGI systems (VGIS) in order to enhance design processes that lead to a more systematic and efficient VGI management. We define VGIS, their main components, and general architectures. Then, we use the service blueprinting technique to conduct the case study of several systems, identifying system actions to find the processes and technologies forming the different functional components of VGIS: elements of the technological infrastructure that implement diverse processes to facilitate participation and data management. Integrated in the data collection component, we also propose a typology of crowdsourcing tasks that—coupled with the functional components—establishes a foundation for VGIS research and design. We characterize these components, arguing that they are necessary in the development of VGIS, however, there is still a need for a more detailed study of the flow of processes and subprocesses and how they work under the criteria of different types of projects to continue facilitating their design.  相似文献   

20.
Geographic information is acquired according to several different underlying models of geographic space. Any meaning inherent within a dataset is intrinsically connected to the model by which it was captured. A design is presented for an integrated geographic information system offering a number of distinct views onto geographic space, of varying degrees of abstraction, to support the needs of an expanded user base. An architecture for such a system is developed by an extension of the traditional three layer architecture used in database design. The movement of data from one level of abstraction to another is formalized by a series of dataset and model transformations operating between four different geographic data models. From this formalism, a functional taxonomy of GIS operations is developed.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号