Bingli Xu

Design and development of Distributed Virtual Geographic Environment system based on web services

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 architecture 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.

Collaborative virtual geographic environments: A case study of air pollution simulation

The integration of high dimensional geo-visualization, geo-data management, geo-process modeling and computation, geospatial analysis, and geo-collaboration is a trend in GIScience. The technical platform that matches the trend forms a new framework unlike that of GIS and is conceptualized in this paper as a collaborative virtual geographic environment (CVGE). This paper focuses on two key issues. One is scientific research on CVGE including the concept definition and the conceptual and system framework development. The other is a prototype system development according to CVGE frameworks for air pollution simulation in the Pearl River Delta. The prototype system integrates air pollution source data, air pollution dispersion models, air pollution distribution/dispersion visualization in geographically referenced environments, geospatial analysis, and geo-collaboration. Using the prototype system, participants from geographically distributed locations can join in the shared virtual geographic environment to conduct collaborative simulation of air pollution dispersion. The collaborations supporting this simulation happen on air pollution source editing, air pollution dispersion modeling, geo-visualization of the output of the modeling, and geo-analysis.

Integration of a computational grid and virtual geographic environment to facilitate air pollution simulation

Air pollution, which is a global environmental problem, has been the hot research area among the scientists in the geoscience community. Air pollution simulation is of low-efficiency caused by the computation-intensive models, such as MM5 or WRF, and the complicated and unfriendly user interface. These issues are addressed in this paper by integrating computational grid and virtual geographic environment (VGE). The computational grid is employed to improve the computation efficiency of air pollution models. The VGE is used as a straightforward and easy to use interface to navigate the air pollution modeling workflow and improve the operational efficiencies of the models with respect to initiation, computation, and output visualization. On the aspect of technique implementation, this paper designs a framework and addresses the methodologies of the integration of computational grid and VGE. The prototype system, which integrates the computation grid of the Chinese University of Hong Kong (CUGrid) and a VGE to facilitate air pollution simulation based on the Mesoscale Model Version 5 (MM5), was developed. Based on the prototype system, a case was tested and the results indicate that the efficiencies of air pollution simulation on the model computation and workflow operation based on MM5 are increased significantly. This success also proves the reasonability of our general contribution of integrating computational grid and VGE to facilitate air pollution simulation.

Software, Data and Modelling News: VGE-CUGrid: An integrated platform for efficient configuration, computation, and visualization of MM5

The platform of VGE-CUGrid integrates a computational grid (CUGrid) and a virtual geographic environment (VGE) to enable an efficient life-cycle process of MM5. The CUGrid is used to speed up MM5 computation. The VGE, which is supported by an underlying GIS system and virtual reality, is adopted as the friendly and efficient interface for initiation, computation, and visualization and analysis of MM5.

A Virtual Geographic Environment for a Simulation of Air Pollution Dispersion in the Pearl River Delta (PRD) Region

The rapid economic development of the PRD (Pearl River delta) has led to severe air pollution. Air pollution control is critical for sustainable development. From a geographic viewpoint, this paper will focus on how to develop a virtual geographic environment (VGE) to study environmental issues. Unlike existing work, our methods pay attention to dynamic 3D volume representation in virtual PRD terrain environment, which make air pollution transportation and dispersion easily understood to public and officers. Moreover, some GIS spatial analysis and real-time interactive operation with VGE will also be implemented to support the management and control of atmospheric pollution. A prototype system is developed to construct a virtual geographic environment for simulating the PRD region air pollution and dynamic interaction. Experimental results prove that the scheme addressed in the paper is effective and feasible.

Real-time visualization of virtual geographic environment using the view-dependent simplification method

A real-time virtual geographic environment (VGE) can serve as interactive, intuitive visualization tools for exploring, analyzing, synthesizing, and simulating multi dimension geo-data and complex geo-phenomena. The VGE scene can be constructed by terrain models, building models, and natural gaseous phenomena models. This paper used a viewdependent simplification method to improve the rendering efficiency of the VGE scene. The continuous level of detail technique(C-LOD) algorithm was adopted to achieve high frame rates by generating an approximate view-dependent triangulation of large terrain scene. Meanwhile image-based rendering techniques such as the imposter billboard were used to speed up the visualization of 3D object models (e.g., 3D building, 3D trees, smoke, cloud and so on). Using the Pearl River Delta (PRD) region in China as a case area, the visualization environment was built to support real-time rendering of larger-scale geo-scene. Experiment results prove that the scheme addressed in the paper can improve the overall efficiency.

Grid based model computation of virtual geographic environment: application in Pearl River Delta air pollution visualization

Virtual Geographic Environment (VGE) is a virtual representation of the physical world, culture world and imaginary world. Compared with GIS, VGE has two core components, which are Data and Model respectively. Many models in VGE are complex and therefore the model calculations for them are very time consuming as well. How to decrease and reduce the required model computation time to improve VGE efficiency will be a vital and key issue for most of the VGE implementation. In this research, we adopt CUGrid as the model computation server, which contains more than two hundred CPUs for fast and intensive computation. With the CUGrid, MM5 based air pollution data in Pearl River Delta is used as the test case for this study. According to the test results, we managed to reduce the required model computation time from the original three months on one specific desktop to several minutes on the CUGrid. Another significance and benefit of this research is that we also able to integrate MM5 with geographic information, which makes concepts on air pollution can easily be understood by the public.

A GI services grid for public health management and disease control

A geographic information services grid (GISG) is an open frame and software system based on grid for discovering, sharing, processing, integrating multi-source and heterogeneous geographic information, and conducting collaborative work. At present, many technologies are introduced and applied to implement sharing, integration and collaboration of geographic information, of which grid computing technology, OpenGIS, and Web services are the most important ones. In this paper, we aim to utilize Open GIS specification and Web services technology to design the architecture of GISG according to OGSA. Specially, GI services are taken as the GISGs center. Based on GISG, we develop designa framework for establish the public health management and disease control system.

System design and implementation of remotely sensed image information services based on grid technology

With the increase of the data amounts received from Remote Sensing (RS), many data can’t be used efficiently in good time because of the traditional service mode such as purchasing data. In fact, many users only want to get some information from RS images, and they don’t want to purchase these images, especially high-resolution images, which is very expensive. Based on Grid technology, we proposed RS information service that can avoid these restricts and offer more rapid and convenient service modes to help people efficiently use RS images. In this paper, we firstly introduce and analyze some major characteristics of RS and Grid technologies. Then, the RS information service system architecture is designed and key technologies such as data management and services management are also discussed. In our system, this design conforms to the OGSA (Open Grid Services Architecture) standard and takes into account the idea of grid service. Finally, the paper designs and implements a prototype system, the result shows the feasibility of the application of RS image information services based on Grid technology. Keywords-Information Service; Grid Technology; Open Grid Services Architecture; Remote Sensing;;

A spatial data 3D-visualization web services for GIS

Data visualization is an important technique that helps in understanding and analysis of complex data. Geo-spatial data is quite different from other kinds of data, for its unique properties of territorial, multidimensional structural and dynamic change. VR technologies have considerable potential to extend the power of geo-spatial data visualization methods which traditional GIS can not provide. Although Virtual GIS can provide the functions of the 3D-visualization analysis for spatial data, these systems are dependent upon specific platforms and programming languages without interoperability. Web services are very suitable for solving above problems. In this paper, we design and implement a spatial data 3D-Visualization web services for publishing multi-dimension geo-data in order to make independent GIS software share distributed geo-information resources including geospatial data and 3D-visualization geo-model, and realize them interoperability. The web services are used to construct the land view with DEM data and remote sensing data based on Java3D, and are deployed in Weblogic8.1 server and published in IBM UDDI registry center on Internet. At last, a client of the web services is created to test the effect of the spatial data 3D-Visualization web services.