Jianqin Zhang

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.

A collaborative virtual geographic environment based on P2P and Grid technologies

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 modeling 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.

Spatial Analysis Services in Virtual Geographic Environment based on Grid technologies

In recent years, spatial data, including Digital Elevation Model (DEM) data and Remote Sensing (RS) images data, is becoming more and more tremendous, and their information also become more and more abundant. So it becomes a great challenge for current spatial information technologies to integrate all diverse and separated data resources and offer more convenient and intuitive geographic information services for complicated geographic problem solving. Virtual geographic environment (VGE) in conjunction with Grid technology can provide us the capability to solve these issues effectively. In this paper, we firstly introduce and analyze the major characteristics of VGE and Grid technologies. Based on Grid technology, we focus on how to build a virtual geographic environment that can integrate resources in high-efficiency and offer powerful geographic information services. The VGE aims to build more intuitive and efficient interactive visualization environments allowing distributed users to implement exploration of large amounts of complicated spatial information and to conduct geographic work. Then we design the VGE system architecture and its implementing mechanism is addressed. Meantime, some key technologies are also discussed. Finally, this paper designs a simple application service. The experiment result shows that the scheme addressed in the paper is efficient and feasible.

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.

Task multi-level decompose in grid-VGE

In order to integrate kinds of data, models and applications in virtual geography environment (VGE), we propose the grid-VGE based on the technology of grid. With regard to the specific applications of grid-VGE, the tasks submitted by users can be divided into several sorts, such as science computing, I/O species, data management, simulating and modeling. With the development of VGE, more and more applications will join the grid-VGE, but they may not belong to any species that has been listed up. Of course, many tasks may be covered by several species. When a user submits a complex and onerous task, the task needs to be decompounded to assign to different locations for implementation. Based on the theoretic of Bernstein by layer upon layer, we decompose the task into many sub-tasks, which will be distributed to certain nodes based on the upper capability hierarchy. And these sub-tasks will cooperate to complete the whole task. In an addition, a status-word will be added to every sub-task which is used to record the status of the sub-task implementation. In the last, we will give an example. The user can ramble and interact with each other in the three-dimension visional scene and can use kinds of peripheral equipments to hence the sense of immersion and interact each other in real time. The experiment results show that decomposition and distribution of tasks regarding grid-VGE are correct and effective for the cooperative implementation of the tasks.