VGE Lab Blog

A Collaborative Virtual Geographic Environment:Design and Development

Tue, 26 Jun 2007 11:22:02 GMT

A Collaborative Virtual Geographic Environment:

Design and Development

Jianhua Gong, Chinese Academy of Sciences, China

Hui Lin, The Chinese University of Hong Kong, Hong Kong

Abstract

A collaborative virtual geographic environment (CVGE) is a 3-D, distributed,and graphical world representing and simulating geographic phenomena and processes to enable geographically distributed users to explore geoproblems and theories and generate hypotheses, and to support geomodel building and validation and collaborative ecological planning. This chapter reports an approach to establishing a CVGE across the Internet, and its application to the collaborative planning of silt dam systems in watersheds through the integration of distributed virtual environments, geographical information systems (GIS), planning models of dam systems, and geocollaboration. The chapter addresses the conceptual and system frameworks of the distributed CVGE, and the 3-D modeling of virtual geographic environments and virtual collaborative studios in addition to the mediated tools for collaboration, such as streaming media based communication, shared whiteboards for text input and graphics drawing, and text-based dialogue. In a case study of the Qiu-Yuan-Gou watershed, Suide County, Shanxi Province, China, a prototype system is designed and developed with Java, Java3D, and VRML. The complete dam systems in the Qiu-Yuan-Gou watershed represent a typical example model of a massive silt dam construction project on the Loess Plateau. The study employs the example model of the watershed to explore the methodologies of collaborative spatial planning of silt dam systems. Using the prototype system, participants

can implement communication with each other via media tools, mainly in the virtual collaborative studio, and 3-D editing of shared dams, calculation of topographic properties, and ideal spatial distribution of dam systems in virtual geographic environment.

Introduction

Geographic environments are open, huge complex systems in which most complicated geoproblems, such as ecologic planning, sustainable urban development, evaluation of large geographic projects, disaster forecasting and early warning, emergency response and process, and ecologic security need to be collaboratively explored and solved by a group of people. Meanwhile, the rapid development of information and communication technologies facilitates the potential to invent many tools to support collaboration, with computer-supported cooperative work (CSCW) becoming an important research field (MacEachren, 2001; Mandviwalla & Khan, 1999). In the GIScience community, the limitations of current geographic information systems only designed for individuals, and the resultant increase in interest in geocollaboration is evidenced by the growing body of work on group decision support systems, public participation GIS, collaborative GIS, and collaborative geovisualization (Batty, Didge, Doyle, & Smith, 1998; Benko, Ishak, & Feiner, 2003; Cheng, Hu, & Ma, 2003; Craig, Harris, & Weiner, 2002; Densham, Armstrong, & Kemp, 1995; Jankowski & Nyerges, 2001; MacEachren & Brewer, 2004). This chapter will focus on the design and implementation of technologies for geocollaboration from the perspective of distributed virtual geographic environments.

The rest of the chapter is organized as follows. In section 2, work related to geocollaboration, with a special emphasis on distributed-virtual environments, is presented through a discussion of relationships with the online community, networked visualization, and Internet/virtual GIS. Section 3 elaborates the design of the conceptual and system framework of collaborative virtual geographic environments. Section 4 presents a prototype system of CVGE, and a case study of the dam systems planning in the Jiu-Yuan-Gou watershed. The last two sections conclude with a discussion of future research trends.

Background and Related Works

Geocollaboration can be defined as a group of people working together in both the same or differing geographical locations and time to accomplish geotasks or to solve complex geoproblems. The study of geocollaboration involves diverse aspects ranging from participants and organization to mediated tools, geoproblem contexts, and supportive environments. From the viewpoint of geocollaboration supportive mediation technologies, this chapter highlights distributed virtual environments supporting different place/same time geocollaboration. Distributed virtual environment technology works to establish distributed, 3-D environments allowing geographicly distributed users to meet and interact virtually with objects and processes, and collaborate with other users in 3-D worlds on the Web (Gong & Lin, 2000; Normand, 1999). In recent years, distributed virtual environments have drawn increasing interest in academic and industrial communities (Blaxxun, 2005; Dykes, Moore, & Wood, 1999; Hibbard, 1998; Oliveira, Shen, & Georganas, 2000; Singhal & Zyda, 1999 ).

From the perspective of online communities, originating from the online textbased or voice-based chat rooms such as the famous Muds (multiuser dungeons) and Tencent OICQ in China, distributed virtual environments are now used to create online, 3-D communities for conducting a variety of activities such as chatting, game playing, forming clubs, virtual house building, and shopping in the virtual mall (Cooper, 2000; OICQ, 2005). Figure 1 illustrates a snapshot of Cybertown, a well-known 3-D Internet community (Cybertown, 2005). In Figure 1, online users are represented as 3-D avatars that can navigate in 3-D worlds and chat with other users. From the perspective of networked computer graphics integrated with CAD and visualization technology, distributed virtual environments are applied to the building and distribution of CAD or visualization environments for collaborative designing or visual data interpretation. Figure 2 shows a distributed CAD design environment called DMUConference (Tecoplan, 2001). In the DMUConference environment, geographically distributed designers can meet virtually and discuss the design of cars.

Applications and importance of virtual reality/virtual environment technology have increasingly drawn attention in the GIScience, modern cartography, and geographic sciences communities (Batty et al. 1998; Faust, 1995; Gong & Lin 2000; Gore 1998; Van Maren & Germs, 2000; Verbree, Maren, Germs, Jansen, & Kraak, 1999). Much effort has been directed towards the integration of the traditional GIS, geographical application models, AutoCAD, and distributed tools such as ActiveX, VRML, Java, and Java3D to construct distributed virtual geoenvironments (GeoVE) on the Internet. Using Java and Java3D, Hibbard et al. (Hibbard, Rueden, Emmerson, Rink, Glowacki, Whittaker, Murray, Fulker, & Anderson ,2005) designed and developed a VisAD system to create applications

that enable many users to implement the visualization of a shared set of numerical geodata and geocomputations. Based on Geometrek’s DeepMatrix 1.1, an existing multiuser virtual environment, Manoharan et al. (Manoharan, Taylor, & Gardiner, 2002) established a collaborative urban planning prototype system to assist shared analysis of urban planning proposals by visualization and interaction with spatial data. MacEachren et al. (MacEachren, Edsall, Haug, Baxter, Otto, Masters, Fuhrmann, & Qian,1999, MacEachren, Cai, Sharma, Rauschert, Brewer, Bolelli, Shaparenko, Fuhrmann, & Wang, 2005) address geospatial virtual environments (GeoVE) and dialogue-assisted visual environments focusing on visual representation, exploratory interaction, visually-enabled dialogue, and team/group collaboration in the context of geovisualization. From the perspective

of geography, Gong and Lin (2000) present the concept of virtual geographic environments, and define a virtual geographic environment as a human-centered environment that represents and simulates geographic environments (physical and human environments), and allows distributed multiusers to implement exploratory geospatial analysis, geocomputation, and geovisualization, and to conduct collaborative work for supporting design and decision. The building of virtual geographic environments needs to integrate such technologies as GIS, distributed virtual environments, and CSCW. The major aim of the virtual geographic environment is to allow traditional geographers to carry out their research work on comprehensive and complex geoproblems in an efficient and innovative way on a data- and graphics-driven integrated platform.

In this chapter, we employ theories and technologies of collaboration and distributed virtual geographic environments to first explore the features and framework of CVGE, and then carry out the design and development of the CVGE system.

Study on Data Collaboration Service for Collaborative Virtual Geographic Environment

Wed, 20 Jun 2007 14:47:50 GMT

Study on Data Collaboration Service for Collaborative

Virtual Geographic Environment

Jun Zhu1,2, Jianhua Gong1, Hua Qi 3, and Tao Song4

[Full Paper Download]

^{1 State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications,}

^{Chinese Academy of Sciences, Beijing 100101, P.R. China}

^{2 Key Laboratory of Poyang Lake Ecological Environment and Resource Development，}

^{Ministry of Education}

^{vgezj@163.com}

^{3 Surveying Engineering Department, Southwest Jiaotong University, 610031, P.R. China}

^{4 GIS Lab, Department of Geoinformatic Engineering, Inha University, Yonghyundong 253,}

^{Namgu, Inchon, S. Korea, 402-751}

Abstract. The use of Collaborative Virtual Geographic Environments (CVGE) is one of the most promising uses of virtual reality in geographic field. Data collaboration can support multi-directional sharing of data and files, allowing ideas and thoughts to be communicated interactively among users. Thus how to integrate diverse and separated data and offer more convenient and intuitive data collaboration service becomes increasingly significant for implementing collaborative work in the CVGE. In this paper, we firstly design a Grid-based CVGE service framework and discuss the data searching mechanism and accessing control. A data collaboration service was built to integrate and share system internal resources and improve collaboration work efficiency. Finally, we built a collaborative virtual environment and implemented data collaboration service in silt dams system planning on a case study area, Jiu-Yuan-Gou watershed of Loess Plateau, China. Experiment results prove that the scheme addressed in the paper is efficient and feasible.

1 Introduction

In recent years, the amount of spatial data is becoming more and more tremendous [1]. However, a lot of data cannot be used efficiently because the rapidly increasing amount of data precludes the presentation of all given data items and the complexity of many datasets surpasses the user’s ability to identify the gist or the underlying concepts [2]. Essentially, solving geographic problem is a process of collaborative work among group members, which are often distributed in geographic space [3]. To facilitate the analysis of simulation data, a variety of experts may be needed. As an integrated technology, collaborative virtual geographic environment (CVGE) offers an tuitively and efficiently interactive visualization environment. The CVGE might vary in its representational richness from 3D geographic spaces, 2.5D and 2D environments to text-based environments, which allows eographically separated users to explore complicated spatial information and conduct collaborative work [4,5]. An essential achievement of the CVGE is that it combines the participants and the information it accesses and manipulates in a single virtual geographic space.

Hence improving the efficiency of data collaboration is very important to keep synchronization in the CVGE collaborative work. In fact, many related works have been implemented to resolve some certain application cases. For example, a visualization environment in a single computer has been developed. So how to integrate data, procedures and algorithms to build and offer more convenient and intuitive data collaboration service in heterogeneous and geographically dispersed environments becomes increasingly significant for collaborative work in the CVGE.

The development of Grid technology endows the CVGE with a promising future. Grid’s concept is coordinated at sharing resources and solving problems in dynamic, multi-institutional virtual organizations [6]. The Grid computing system can provide different kinds of services for users [7,8]. Essentially, Grid user sees a large virtual computer despite of the fact that the resources are geographically distributed and connected over the worldwide networks [9]. Based on the concepts and technologies of Grid and Web Service communities, this architecture defines the uniform exposed service semantics (Grid Service). The OGSA (Open Grid Services Architecture) [10] can provide building blocks that can be used to implement a variety of higher-level Grid services such as distributed data management services. This framework is very flexible because services can be implemented and composed in a variety of different ways.

By using Grid computing, the CVGE can integrate and share all internal resources to create a big high-performance computing environment. Since the core of the OGSA is the service idea, the OGSA-based CVGE can integrate services across distributed, heterogeneous and dynamic collaboration environment formed from the disparate resources with a single system and/or from external resources sharing and service provider relationships. In this paper, we pay attention to build up a data collaboration service to high-efficiently support collaborative work in the CVGE.

The rest of this paper is organized as follows. In section 2, we focus on how to build a data collaboration service, some key problems such as Grid-based CVGE service framework, data searching mechanism, data accessing control and service implementing are discussed in detail. A simple prototype system was developed and a

data collaboration experiment was implemented as shown in section 3. Finally, some concluding remarks are given in section 4.

Design and Development of Distributed Virtual Geographic Environment System Based on Web Services

Tue, 19 Jun 2007 09:58:34 GMT

Design and Development of Distributed Virtual Geographic

Environment System Based on Web Services

[Full Paper Download]

Jianqin Zhang(a,c*), Jianhua Gong (a), Hui Lin (b), Gang Wang (c),

JianLing Huang (c), Jun Zhu (a), Bingli Xu (a), Jack Teng (d)

^{a State Key Laboratory of Remote Sensing Science, Jointly Sponsored by the Institute of Remote Sensing}

^{Applications of Chinese Academy of Sciences and Beijing Normal University, Beijing 100101,P.R. China}

^{b Joint Laboratory for Geoinformation Science The Chinese University of Hong Kong Shatin, Hong Kong}

^{c Beijing Transportation Information Center, Beijing 100055,P.R. China}

^{d Resource Management and Environmental Studies, University of British Columbia, Canada}

ABSTRACT

This paper aims to design and develop a Distributed Virtual Geographic Environment (DVGE) system. A DVGE system is an Internet-based virtual 2D and 3D environment that provides users with a shared space and a collaborative platform for publishing multidimensional geo-data, and for simulating and analyzing complex geo-phenomena. Users logging into the system from different clients can share distributed geo-information resources, including geo-data and geo-models, and can complete collaborative tasks. Web service technology provides effective solutions for constructing DVGE systems because of its ability to support multi-platform, multi-architecture, and multi-program-language interoperability on the Internet, but also because of its ability to share programs, data, and software. This paper analyzes the characteristics, relevant technologies, and specifications of web services, such as grid services, Open Geo-data Interoperability Specifications (OpenGIS), and Geography Markup Languages (GML). The rchitecture and working mechanisms of the DVGE system based on web services are then elaborated. To demonstrate DVGE systems based on web services, we examine a case study of water pollution in Yangzhou City, Jiangsu Province, China, using a prototype DVGE system that is developed with Jbuilder9.0 and Java3D 1.0 packages, and the Weblogic platform 8.1.

Keywords: virtual environment, virtual geographic environment, distributed computing, web services, J2EE, grid services

1. INTRODUCTION

A Geographic Information System (GIS) is designed to provide storage, retrieval, analysis, visualization, and mapping capabilities for spatial information data, such as road networks, power transmission networks, and land use information data [27]. Virtual Reality (VR) derives from three-dimensional (3D) computer graphics and provides an intuitive human-computer interface

that gives the user the impression of being in a computer-generated virtual world [16]. VR technologies, when used as a medium for geographic visualization and analysis, have considerable

potential to extend the geo-information visualization methods of 2D maps or traditional GIS. Thus, the applications and importance of VR technology have increasingly attracted the interest of researchers in the field of geographic information science.

Virtual geographic environment (VGE) was first proposed in 1999. In contrast to current data-centered GIS, a VGE is a human-centered environment. From the perspective of geography, VGE is an environment concerned with the relationship between avatar-based humans and 3-D virtual worlds [7, 6]. From the perspective of information systems, VGE is an advanced information system that combines GIS with VR technology [14]. At present, there has been much research into VGE, allowing for VGE application systems to be successfully designed and implemented [13]. However, these systems are dependent upon specific platforms and programming languages that lack interoperability, making the sharing of resources and collaborative work difficult. To address this, we aim to design and develop a distributed VGE (DVGE) system. A DVGE system is a virtual Internet-based 2D and 3D environment that provides users with shared space and a collaborative platform for publishing multidimensional geo-data, and for simulating and analyzing complex geo-phenomena. Users logging into the system can be from different clients, which are often not in the same geographic area, but can nevertheless share distributed geo-information resources, including geo-data and geo-models, and can also complete collaborative tasks.

There are two key challenges to a DVGE system: sharing geo-information resources and implementing collaborative work. These two key problems can be solved using new computer technologies, such as web services and grid computing. Using certain specific regulations, grid

computing aims to share all kinds of resources, including data, applications, and computing capacity; these regulations can ensure the compatibility of all the resources in the grid system [3]. But, grid computing is derived from distributed parallel computing and high-performance network computing, both of which depend on computer hardware that are too expensive to be used universally. Despite this, the Global Grid Forum began to improve the possibility of converging

grid services with web services, to ultimately merge into a single service [12]. Web services are platform-independent and language-independent, since they use standard Extensible Markup Language (XML) languages. Besides web services’ natural capability for cross-platform interoperation, they also have the following advantages: 1) sharing not only programs, but also

data; 2) easy integration with other programs; 3) easy re-use of software; 4) simple configuration and deployment [11]. Web services are thus highly suitable for constructing an Internet-scale DVGE system. This paper reports the construction of a DVGE system, which is based on web services technology, and which allows traditional geographers to carry out efficient and innovative research, on comprehensive and complex geo-problems, using a data and graphics-driven distributed and collaborative platform.

The paper is organized as follows: Section 2 briefly introduces VGE and reviews related work on VGE, and the relevant technologies, such as web services, grid services, OpenGIS, and GML. Section 3 describes the DVGE system architecture based on web services, and the working mechanisms of DVGE system. Section 4 describes a prototype DVGE system that was established to illustrate the effectiveness of the DVGE system using Jbuilder9.0, Java3D1.0, Weblogic Platform 8.1. Section 5 discusses our research. Finally, section 6 concludes with a discussion of our research.

An International Conference on Developments in Visualization and Virtual Environments in Geographic Information Science

Mon, 18 Jun 2007 10:39:11 GMT

First Announcement

Virtual Geographic Environments

An International Conference on Developments in Visualization and
Virtual Environments in Geographic Information Science

7-8 January 2008

The Chinese University of Hong Kong

Geovisualization involves theories, methods, software, and applications for visualizing geographic phenomena in real or virtual worlds. This two day conference will address progress and developments in research and applications in this field, bringing together the world’s key experts to present the state of the art and discuss future developments. The technologies to be discussed will cover news ways of visualizing geographic phenomena as information spaces, as virtual and augmented and multi-media realities (VR and AR), as well as new ways of communicating such visualizations and representations in digital environments. There will be a focus on applications which involve experts and users in the context of collaborative decision-making, spatial decision support systems, and user participation. Some of the areas that the meeting will cover are:

• Conceptual advances in temporal and dynamic representations
• Visualizing geographic phenomena in new information spaces
• New techniques of display and communication
• Real and abstract representation in virtual environments (VEs)
• Virtual environments for exploring and discovering spatial information
• Use of metaphors and analogies in Geovisualization
• Locomotion, navigation, scale, and distance in Geovisualization
• Dialogue-enabled human-system and human-human geocollaboration
• Human-computer interfaces involving spatial visualization
• Collaborative and participative (geo)visualization
• The development of 3D and 4D visualization environments
• Mobile Geovisualization in the lab and in the field
• Web and grid-based technologies for visualization
• Public domain GIS, cartography and visualization
• New hardware technologies for visualization

The program committees will organize the meeting around these and related themes. The conference will aim to present a comprehensive synthesis of basic development and applications in virtual geographic environments, illustrating the state of the art and charting directions for future research.

Abstracts must be submitted by May 31, 2007 and final papers by October 31, 2007. Papers will be posted on the web site prior to any decisions about future publication in book and/or journal form.

Organizer: Institute of Space and Earth Information Science
The Chinese University of Hong Kong, Hong Kong, China

International Advisory Board

Shupeng Chen, Co-chair (CAS, Beijing, China)
Michael Goodchild, Co-chair (UCSB, USA)
Peter Fisher, (City University, UK)
Jun Gao, (ZZISM, China)
Yee Leung, (CUHK, Hong Kong)
Deren Li, (Wuhan University, China)
Paul Longley, (UCL, UK)
Liqiu Meng, (TUM, Germany)
Jiulin Sun, (CAS, China)
Vladimir Tikunov，(MSU, Russia)
Anthony Yep, (HKU, Hong Kong)

International Program Committee

Michael Batty, Co-Chair (UCL, UK)
Hui Lin, Co-Chair (CUHK, Hong Kong)

Gennady Andrienko (FhG IAIS, Germany)
Ian Bishop (University of Melbourne, Australia)
Katy Borner (Indiana University, USA)
Ken Brodlie (University of Leeds, UK)
Bill Cartwright (RMIT, Australia)
Martin Dodge (University of Manchester, UK)
Jason Dykes (City University, UK)
Rob Edsall (Arizona State University, USA)
Sarah Frabrikant (University of Zurich, Switzerland)
Mark Gahegan (Penn State University, USA)
Jianya Gong (Wuhan University, China)
Andrew Hudson-Smith (UCL, UK)
Menno-Jan Kraak (ITC, Netherlands)
Andrew Lovett (UEA, UK)
Juval Portugali (Tel Aviv University, Israel)
Carlo Ratti (MIT, USA)
Ifan Shepherd (Middlesex University, UK)
Ryosuke Shibasaki (University of Tokyo, Japan)
Andre Skupin (San Diego State University, USA)
Jo Wood (City University, UK)
Chenghu Zhou, (CAS, China)

Local Organizing Committee

Hui Lin, Chair (CUHK, Hong Kong)
Jianhua Gong, (CAS, China)
Bo Huang, (CUHK, Hong Kong)
Bin Jiang, (HKPU, Hong Kong)
PC Lai, (HKU, Hong Kong)
Guonian Lu, (NNU, China)
Hanqiu Sun, (CUHK, Hong Kong)
Jinyeu Tsou, (CUHK, Hong Kong)
Xiong You, (ZZISM, China)
Qing Zhu, (WU, China)

The workshop web site announcing further details is at
http://www.iseis.cuhk.edu.hk/vge/

A Collaborative Virtual Geographic Environment Based on P2P and Grid Technologies. Information Science (SCI）

Fri, 15 Jun 2007 11:03:07 GMT

A Collaborative Virtual Geographic Environment Based on P2P and Grid Technologies*

Jun Zhu ^a,*, Jianhua Gong^a, Weiguo Liu^b, Tao Song^c, Jianqin Zhang^a

[Full Paper Download]

^a State Key Laboratory of Remote Sensing Science, Institute of Remote Sensing Applications, Chinese Academy of Sciences, Beijing 100101, China;

^b Department of Geography and Planning, The University of Toledo, Toledo, OH, 43606, USA

^c GIS Lab, Department of Geoinformatic Engineering, Inha University, Yonghyundong 253, Namgu, Inchon, S.Korea, 402-751

Abstract: Solving a geographic problem usually requires collaborative work among a group of people in different geographic locations. Collaborative virtual geographic environment (CVGE), an integrated technology, offers an intuitive, efficient, and interactive visualization environment through which geographically separated users can explore complicated spatial information and conduct collaborative work. In this paper, two new technologies, Peer-to-Peer (P2P) and grid computing, are tightly coupled to develop a CVGE system. This paper evaluates the potential contributions of the P2P and grid technology to CVGE systems. Using a Grid-based system architecture efficiently integrates and shares geographically distributed resources as well as modelling procedures built on different platforms. To offer a shared and interactive virtual collaborative geographic environment for resolving geographic problems, we developed several P2P services including a terrain visualization collaboration service and a video collaboration service. Finally, a CVGE prototype system is implemented for collaboration on silt dam planning on the Loess plateau. The experimental results show that the scheme developed in this paper is efficient and feasible.

Keywords: Collaborative Virtual Geographic Environment (CVGE); Peer-to-Peer (P2P); Grid Services; Open Grid Services Architecture (OGSA); Collaborative Work

1. Introduction

The advances in remote sensing, geographic information system (GIS), and other survey technologies over the course of last two decades have dramatically increased our capabilities to collect large amounts of multi-attribute geo-spatial data. Geography has changed from a data and computation-poor discipline to an environment rich in data, computational tools, and resources. However, the value of geographic data cannot be fully realized when information content is difficult to describe and not successfully applied. Many datasets surpass the user’s ability to identify its gist and the underlying concepts because of their complexity (Lin and Zhu 2005). Visualization, an advanced technology of studying human-computer interaction, provides a new paradigm for visually and interactively exploring large amounts of complicated geo-spatial information. As an interdisciplinary of visualization and GIS, virtual geographic environment (VGE) was proposed in 1999. Unlike the traditional data-centered GIS, VGE is a human-centered environment that represents and simulates geographic environments (both physical and human environments). It allows geographically distributed multi-users to visually explore spatial information, design models, implement complex computation, and to provide support for decision-making (Gong and Lin 1999, 2000).

With the distributive nature of companies and research organizations, collaborative work among geographically dispersed workers has become very popular and important in both academia and industry. Research studies show that collaborative work involves the interaction of individual and group efforts where considerable complex information needs to be exchanged. Collaborative virtual environments (CVEs) are distributed virtual reality systems that offer graphical environments for individuals to exchange information and to work collaboratively. Collaborative virtual geographic environment (CVGE) integrates CVE and VGE to support collaborative work on geospatial information exploration and analysis by creating a digital landscape environment. It has drawn increasing attention in the fields of collaborative GIS and collaborative virtual environments (Wang 2002). The CVGE can be applied to many areas such as geographic game, public participation, city management and planning, resource development planning and management, natural disaster evaluation, prevention and reduction, collaborative scientific research, and virtual geographic education and training.

CVGE integrates the technologies of computer network, visualization, and spatial information. There are two important components in a CVGE system: distributed system architecture and virtually shared collaborative environment. Thus, the implementation of an open and flexible architecture and a more intuitive, efficient, and interactive visualization collaborative environment is crucial to the success of a CVGE system in the real world. The grid and Peer-to-Peer (P2P) technologies developed in the field of computer network provide such a platform for sharing resources and services across distributed, wide area networks. Integration of the two technologies with visualization in a CVGE system has become very promising.

Grid technologies aim at supporting resource sharing and problem solving in dynamic, multi-institutional virtual organizations (Foster et al. 1998). The essential property of Grid technologies is using services to implement different Grid functions requested by multi-users. By using grid computing, CVGEs can integrate and share all internal resources to create a high-performance computing environment (Foster et al. 2001, 2002a). Also, Grid technology based CVGE can integrate different kinds of services across distributed, heterogeneous, dynamic collaborative environment formed from the disparate resources within a single system and/or from external resources sharing and service provider relationships (Foster et al. 2002b). A true P2P system is one where all nodes in a network join together dynamically to participate in traffic routing-, processing- and bandwidth intensive tasks. It has many advantages over traditional client-server networks in terms of data sharing. With P2P, computers can share both data and resources through direct communication with each other (Georgios et al. 2004, Sudip et al. 2005, Cai et al. 2005). Thus, by using P2P, CVGEs can potentially improve the efficiency of resource usage and collaboration.

This paper mainly focuses on the design and implementation of a collaborative virtual geographic environment system using Grid and P2P technologies. Several key techniques, such as data organizing and scene simplifying, which are needed to build a real time collaborative geographic scene, are discussed in the following sections. The system aims to efficiently integrate disparate resources and to offer powerful geographic information services, and to allow large-scale distributed users to explore spatial information and conduct collaborative work.

The remainder of this paper is organized as follows. In section 2, the features of Grid and P2P technologies are introduced and their advantages are discussed. In section 3, a Grid based CVGE system is presented and two types of P2P application services are designed. In section 4, a prototype system that includes a terrain visualization collaboration service and a video collaboration service is implemented. Finally, conclusions and future research plans are addressed in section 5

Wenhang Li finished his doctoral thesis defense successfully on June 10, 2007.

Thu, 14 Jun 2007 13:59:00 GMT

Wenhang Li finished his doctoral thesis defense successfully on June 10, 2007. His doctoral dissertation is entitled “Study on Theories and Key Technologies for Collaborative Virtual Geographic Studio ” .

This is his doctoral thesis summary:

Study on Theories and Key Technologies for Collaborative Virtual Geographic Studio

Abstract

Geographic system is one open complex giant system, which indicates that new methods are needed for complex geographic issues solution. Collaborative Virtual Geographic Studio (CVGS) was then proposed, based on thought of collaboration from CSCW (Computer Supported Cooperative Work) and CVE (Collaborative Virtual Environment), thought of mobile work from mobile technology, and thought of complexity solution from metasynthesis and hall for workshop of metasynthetic engineering.

CVGS is one distributed three-dimensional platform for group discussion on geographic issues. It is one human-centered human-computer system, composed of Internet and mobile network, computers and mobile instruments involved.

CVGS is studied from three levels of theory, techniques and application in this paper, the main content are:

l At the theory level. (1) “Role theory” is proposed for social property of group participants. In group discussion, participants have different “social status”, play different “roles”, have different “rights”, as well as different “obligations”, and build up different “relationship” on basis of these. (2)The “5A” model is proposed for geographical researches from view of group participation. “5A” is Anyone, Anytime, Anywhere, Anything and Association. The flexible “5A” model has little restriction with participants, space (including movement status), time (in discussion period), and the content of geographic issues. All these are done with tight association between each other. (3) A 4-part group discussion process is proposed: collaborative reconstruction for geographic issues, collaborative analysis for geographic data, group discussion, and decision-making. The process is a positive feedback cycle. At the same time, measures for “concept conflict”, “language conflict”, “group thinking”, and “emergency” are emphasized. (4) Study on geo-ontology. It is pointed out that geo-ontology is different from other ontology because of its spatial characters. So it is suggested that ontology would have its scope extended when applied into geography. Meanwhile, the paper notes that ontology (including geo-ontology) should combine with graph theory for knowledge expression, and more important, for knowledge calculation visually with support of graph theory. “Knowledge Topology Network (KTN)” is then prospected.

l At the technique level. CVGS is positioned as a heterogeneous system, composed with heterogeneous networks of Internet and mobile network, with heterogeneous clients of computers and mobile instruments. Asymmetry is the obvious property of CVGS, with computation capability asymmetry, storage capability asymmetry, and display capability asymmetry as typical ones. To make CVGS agree with the concept of “Collaboration”, computation transfer and storage transfer between different terminals are proposed. Key technologies are as follows: (1) Three-dimensional scene collaboration among heterogeneous terminals. It is still a hard work to simulate 3-dimensional, let alone collaboration with computer. To solve this problem, “Stream media based collaboration” is proposed. The main idea is that to transfer computation requirement from mobile instruments to computer to render the complex content of the 3-dimensional virtual scene, and send the result back as a stream. Complex virtual scene contents, such as particle systems, multi-agent systems, and videos can then be simulated on mobile instruments. (2) Long-time connection maintenance mechanism for mobile instruments. Mobile instruments have the so-called “roll-back effect” which makes mobile instruments unable to keep network connection. This is unsuitable for choose mobile instruments as one part of CVGS. To solve this problem, “long-time connection maintenance” is proposed, that is, to separate sent-messages from gotten-messages to avoid the “roll-back effect”. The mechanism enables mobile instruments long-time collaborations with computer during geographic issues discussion.
As to the group interaction, workflows in collaborative issue reconstruction, collaborative data mining, multi-perceptive group interactions, and group decision-making are studied. Key technologies such as CVGS data organization, scene consistency maintenance, right assignment and other techniques are studied. Based on the above technologies, a CVGS prototype has been programmed using Java SE, Java ME, and Java 3D.

l At the application level. “Dam system planning project judgment” is chosen as the case for CVGS application. Dam system is one of the vital measures for water and soil conservation for loess plateau and for health of Yellow River, while dam system planning project judgment is the final and key stage for dam system planning. Collaborative project judgment is first proposed according to “5A” model, which is to involve experts, workers, and citizens, wherever they are, and whatever their movement status, to make comments on different projects, and to select the best one among those projects. Group discussion steps, collaborative issue reconstruction, collaborative data analysis, social group interaction, and project selection are all test. The result shows that it is feasible.

Key words: Group geographic research, geo-collaboration, distributed virtual environment, collaborative virtual environment, virtual geographic environments, mobile computation and collaboration, role theory, geo-ontology

Introduction to Virtual Geographic Environments(VGE)

Thu, 10 May 2007 15:35:29 GMT

Introduction to Virtual Geographic Environments

[Full Introduction Download]

GONG Jianhua

Institute of Remote Sensing ApplicationsChinese Academy of Sciences, Beijing ,China

Email:jianhuagong@sina.com

Homepage：http://www.vgelab.org

1 Definition of VGE
A virtual geographic environment (VGE) is a multi-user shared,intelligent, virtual environment representing the real geographic environment to conduct geo-spatial analysis, to carry out geo-visualization, to support collaborative work, planning and decision making, as well as to serve for training, geographic education, and entertainment.

2 VGE Modeling and Simulation

Examples

•Spatial (Geometric) Modeling;

•Geo-Process Simulation ;

•Behavior Simulation;

•Support Dialogue and Planning.

3 Current VGE Research

Topics

•Modeling of Very Large Geographic Environments for Distributed VGE (Compression Algorithms, LOD, etc.)

•Streammedia incorporated into the multi-media VGE for Collaboration

•Grid-based VGE Systems for handling complex geo-problems

•Distance and Collaborative Visualization in VGE

•Intelligent VGE ( Agents, Handling of a large volume of messagesbetween agents )

•Visual data mining and Geo-Knowledge Discovery

•VGE for Augmented Reality (Mobile mixed reality )

•Spatial Cognition and Collective Thinking

•VGE for establishing digital city

•VGE for supporting crisis (emergency) management , environmentalassessment of large project, etc.

Book List: Publication

Tue, 19 Jun 2007 10:02:09 GMT

Publication

Jun Zhu,Jianhua Gong, Weiguo Liu, Tao Song, Jianqin Zhang: A Collaborative Virtual Geographic Environment Based on P2P and Grid Technologies
Abstract: Solving a geographic problem usually requires collaborative work among a group of people in different geographic locations. Collaborative virtual geographic environment (CVGE), an integrated technology, offers an intuitive, efficient...
Jianhua Gong, Hui Lin: A Collaborative Virtual Geographic Environment: Design and Development
A collaborative virtual geographic environment (CVGE) is a 3-D, distributed,and graphical world representing and simulating geographic phenomena and processes to nable geographically distributed users to explore geoproblems and theories ......
Jianqin Zhang, Jianhua Gong, Hui Lin, Gang Wang, JianLing Huang, Jun Zhu, Bingli Xu, Jack Teng: Design and Development of Distributed Virtual Geographic Environment System Based on Web Services
ABSTRACT: This paper aims to design and develop a Distributed Virtual Geographic Environment (DVGE) system. A DVGE system is an Internet-based virtual 2D and 3D environment that provides users with a shared space and a collaborative platform...

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4 Undergraduate Students
2 Ph.D. students
1 Research Fellows

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