Digital Earth from vision to practice: making sense of citizen-generated content

Abstract

The vision of Digital Earth (DE) put recently forward under the auspices of the International Society for DE extends the paradigm of spatial data infrastructures by advocating an interactive and dynamic framework based on near-to-real time information from sensors and citizens. This paper contributes to developing that vision and reports the results of a two-year research project exploring the extent to which it is possible to extract information useful for policy and science from the large volumes of messages and photos being posted daily through social networks. Given the noted concerns about the quality of such data in relation to that provided by authoritative sources, the research has developed a semi-automatic workflow to assess the fitness for purpose of data extracted from Twitter and Flickr, and compared them to that coming from official sources, using forest fires as a case study. The findings indicate that we were able to detect accurately six of eight major fires in France in the summer of 2011, with another four detected by the social networks but not reported by our official source, the European Forest Fire Information Service. These findings and the lessons learned in handling the very large volumes of unstructured data in multiple languages discussed in this study provide useful insights into the value of social network data for policy and science, and contribute to advancing the vision of DE.     

Overview and preliminary idea for building Digital Earth with Grid computing technology

Abstract

Digital Earth is an important field of information technology and a research frontier of geosciences in the 21st century. So far, the Grid computing technique is one of the best solutions for Digital Earth infrastructure. Digital Earth can only be realised through the interaction of people, heterogeneous computing resources, information systems, and instruments, all of which are geographically and organisationally dispersed. Earth observation (EO) includes information acquisition, processing and applications. Information acquisition provides a vast amount of spatial data for building the fabric resource infrastructure. Information processing means that spatial information processing middleware is used with large amounts of secure Grid computing resources for real-time processing of all kinds of spatial data. We are currently working on the development of core-middleware for EO data processing and applications for the Digital Earth Prototype System, which is available in the Institute of Remote Sensing Applications (IRSA), Chinese Academy of Sciences (CAS) The further results will be available soon.     

一种自发地理信息采集方法研究

本文针对自发地理信息(VGI),提出了基于OpenLayers的信息采集方法。采用VGI的研究理念,将移动应用到自发地理信息中,基于Rest Web Service,利用Openlayers,进行数据的创建、编辑、浏览和采集。使用这种开源的软件,使得聚集大家的力量打破组织边界、持续创造出更高质量、更安全、更易用的软件成为可能。     

建设国家对地观测体系,构筑"数字地球"

论述了“数字地球”的特征与重要意义,指出对地观测是“数字地球”的核心内容之一。建议中国不失时机地组织建设国家对地观测体系。该体系可在信息获取、处理与应用３个层面上构建,并提出近期中国对地观测应优先发展的领域,以持续地为“数字地球”发展作贡献     

信息高速公路、空间数据基础设施与数字地球

本文叙述国家信息基础设施（ＮＩＩ）、国家空间数据基础设施（ＮＳＤＩ）和数字地球的概念与相互关系,通过讨论分析,对如何推动我国信息高科技发展提出了若干有价值的建议。     

迎接"数字地球"的挑战

从地球科学发展战略的角度,分析了“数字地球”对中国的挑战以及“数字地球”本身所面临的挑战,论述了发展“中国数字地球”的必要性和可能性,提出了发展“中国数字地球”的战略措施     

数字地球中的数据处理理论

数字地球这一概念一经提出，立即引起了全世界的广泛关注，数字地球对于促进国民经济的发展、满足社会发展的需要以及迎接信息社会的挑战都具有非常重要的意义。数字地球的基础和关键是数据，文中首先扼要归纳了数字地球中数据的特点，然后重点介绍了数字地球中的数据处理理论，并对数字地球中的数据处理理论这一领域今后的发展作了展望。     

"数字地球"的体系结构

根据我们一年来对“数字地球”的研究,从地理信息与信息技术发展和信息化社会的角度出发,系统地介绍了“数字地球”涉及的研究内容、关键技术、应用前景等问题,比较客观地阐明了“数字地球”的相关内容。     

Digital Earth: a new challenge and new vision

ABSTRACT

Digital Earth has seen great progress during the last 19 years. When it entered into the era of big data, Digital Earth developed into a new stage, namely one characterized by ‘Big Earth Data’, confronting new challenges and opportunities. In this paper we give an overview of the development of Digital Earth by summarizing research achievements and marking the milestones of Digital Earth’s development. Then, the opportunities and challenges that Big Earth Data faces are discussed. As a data-intensive scientific research approach, Big Earth Data provides a new vision and methodology to Earth sciences, and the paper identifies the advantages of Big Earth Data to scientific research, especially in knowledge discovery and global change research. We believe that Big Earth Data will advance and promote the development of Digital Earth.     

A stream-based Parasitic Model for implementing Mobile Digital Earth

A Parasitic Model is proposed in this study for Digital Earth running on mobile phones through a mobile network. Because of mobile phones' limited capabilities in high-performance computing, rendering, storing, and networking (CRSN), these functions are accomplished by a superior host computer in this model. Rendered virtual scenes are compressed in a time-series as a data stream and are sent to the mobile phone through a mobile network, thus allowing Digital Earth to be operated on a mobile phone. This study examines a prototype and shows that a Mobile Digital Earth based on a Parasitic Model can achieve functionality beyond the mobile phone's actual hardware capabilities and can reduce network traffic. These results demonstrate quasi-real-time interactions, but with bandwidth increases in next-generation mobile networks such as 4G and 5G, there is potential for real-time interactions in the near future.     

Hexagonal connectivity maps for Digital Earth

Geospatial data are gathered through a variety of different methods. The integration and handling of such datasets within a Digital Earth framework are very important in many aspects of science and engineering. One means of addressing these tasks is to use a Discrete Global Grid System and map points of the Earth's surface to cells. An indexing mechanism is needed to access the data and handle data queries within these cells. In this paper, we present a general hierarchical indexing mechanism for hexagonal cells resulting from the refinement of triangular spherical polyhedra representing the Earth. In this work, we establish a 2D hexagonal coordinate system and diamond-based hierarchies for hexagonal cells that enables efficient determination of hierarchical relationships for various hexagonal refinements and demonstrate its usefulness in Digital Earth frameworks.     

数字地球与“地相学”

本文通过对数字地球的诠释,结合与地相学的本质联系,论述了二者的形成与发展的关联程度,提出了数字地球是地相学的“量化”;地相学是数字地球的理论支撑与生存、发展的土壤,也是数字地球的学科定位“解”。进而,阐明数字时空的实现是数字地球更宽泛的归宿。     

数字地球与3维地理信息系统研究

美国副总统戈尔关于“数字地球”的演讲引起许多国家政界、学术界的关注。基于“数字地球”的概念,在全球信息数字化过程中,３维地理信息系统起着重要作用。由于空间对象和３维ＧＩＳ的复杂性,在处理各种空间现象时,如地质现象的表示和矿山应用,宜根据实际应用的需要,采用不同的数据结构和可视化方式,包括２维、２．５维、３维的以及它们的结合,以取得良好效果和效益。     

A framework for user-generated geographic content acquisition in an age of crowdsourcing

ABSTRACT

Obtaining useful geographic information from the flood of user-generated geographic content (UGGC) data is of significant interest, but comes with challenges in an age of crowdsourcing. To address this issue, we adopt Maslow’s model of human needs to frame UGGC. Synthesizing across literature about volunteered geographic information and participatory GIS, we present a conceptual framework for characterizing collection of UGGC. The framework is composed of multiple dimensions and levels that include perspectives about motivations, participatory methods, and participants. We also articulate four levels of participants (stakeholders, core-engaged participants, semi-core-engaged participants, and engaged citizens) together with four work principles (communication, cooperation, coordination, and collaboration). Finally, a case study describes an example we use to evaluate the conceptual framework for its suitability in design of a UGGC system. We conclude by reflecting on how and why this framework offers a valuable perspective for deriving useful geographic information and offer future research directions.     

A New Algorithm for Continuous Area Cartogram Construction with Triangulation of Regions and Restriction on Bearing Changes of Edges

Collective intelligence is the idea that under the right circumstances collections of individuals are smarter than even the smartest individuals in the group, that is a group has an “intelligence” that is independent of the intelligence of its members. The ideology of collective intelligence undergirds much of the enthusiasm about the use of “volunteered” or crowd-sourced geographic information. Literature from a variety of fields makes clear that not all groups possess collective intelligence, this article identifies four pre-conditions for the emergence of collective intelligence and then examines the extent to which collectively generated mapping systems satisfy these conditions. However, the “intelligence” collectively generated maps is hard to assess because there are two difficult to reconcile perspectives on map quality – the credibility perspective and the accuracy perspective. Much of the current literature on user-generated maps focuses on assessing the quality of individual contributions. However, because user-generated maps are complex social systems and because the quality of a contribution is difficult to assess this strategy may not yield an “intelligent” end product. The existing literature on collective intelligence suggests that the structure of groups is more important than the intelligence of group members. Applying this idea to user-generated maps suggests that systems should be designed to foster conditions known to produce collective intelligence rather than privileging particular contributions/contributors. The article concludes with some design recommendations and by considering the implications of collectively generated maps for both expert knowledge and traditional state sponsored mapping programs.     

Advancing Digital Earth: beyond the next generation

The Digital Earth (DE) movement is gaining momentum. Much of it is unstructured. This paper examines a number of recent developments including those in health sensors (Wearable Absence, Q-Sensor, and Guardian Angels) and systems frameworks (Gelernter's Mirror Worlds, Virtual Australia, and New Zealand). Consideration is given to the implications of DE for citizens and on citizen science, including those of ethics. A suite of principles to guide the development of DE is proposed.     

A novel approach for constructing a 3D model based on registering a mono image on a 3D model,applicable in Digital Earth

The effect of Digital Earth on our life is vital. Developing and updating Geospatial data in Digital Earth is also essential. This paper presents the application of a new approach of image registration in Digital Earth. The approach was developed based on registering a mono photograph on a master 3D model. The result is a 3D vector model, which can be broadly applied in visualisation, mapping, geographic information system (GIS), planning, change detection, as well as Digital Earth. The approach does not require parameters of correction for transformation. The accuracy of the output depends on the accuracy of the master data. This approach is very versatile and able to register any image on the digital elevation model, digital surface model and topographic 3D model.     

Rating crowdsourced annotations: evaluating contributions of variable quality and completeness

Crowdsourcing has become a popular means to acquire data about the Earth and its environment inexpensively, but the data-sets obtained are typically imperfect and of unknown quality. Two common imperfections with crowdsourced data are the contributions from cheats or spammers and missing cases. The effect of the latter two imperfections on a method to evaluate the accuracy of crowdsourced data via a latent class model was explored. Using simulated and real data-sets, it was shown that the method is able to derive useful information on the accuracy of crowdsourced data even when the degree of imperfection was very high. The practical potential of this ability to obtain accuracy information within the geospatial sciences and the realm of Digital Earth applications was indicated with reference to an evaluation of building damage maps produced by multiple bodies after the 2010 earthquake in Haiti. Critically, the method allowed data-sets to be ranked in approximately the correct order of accuracy and this could help ensure that the most appropriate data-sets are used.     

"数字地球"战略及其制高点

科学技术本来就是双刃剑。“数字地球”战略可能有助于全球信息资源的共享,全球化经济贸易的繁荣,同时也威胁着发展中国家的权益与安全。中国既要积极参与,更要独立自主。实现国家信息化建设是基础;应付“数字地球”的挑战是对策,不能混淆,不能等同。各国不是站在同一起跑线上出发的。必须扬长避短,发挥优势,及时占据制高点。     

浅论自发地理信息的数据管理

自发地理信息（volunteered geographic information,VGI）由大众志愿者自发标报,导致其可信度具有诸多不确定性,但目前的研究工作很少考虑用户信誉对于VGI质量的影响,因此提出基于用户信誉的VGI可信度计算模型。首先提出了VGI的用户信誉模型,模型综合考虑了用户的初始信誉和评价信誉两方面,在此基础上综合地理要素的编辑过程和贡献者的信誉等因素发展了地理对象的可信度计算模型。最后采用OpenStreetMap的真实历史数据中的线对象进行实验,实验结果表明,线要素的质量和可信度值呈正相关关系。本文从可信度的角度来评价自发地理信息,为VGI的质量评价和筛选提供了新的视角。