| Computer hardware resources can be connected on the Internet; web pages can be linked on the World Wide Web. And now, the Grid provides a network infrastructure that enables the geographically distributed computers to be integrated into a virtual supercomputer via the computer networks. We can implement on sharing all grid resources, including computing, storage, data, information, knowledge, and software resources on the Grid. With the emergence of the concept of Open Grid Services Architecture (OGSA), Grid Computing technology originally motivated and supported from sciences and engineering requiring highend computing for sharing geographically distributed computing resources is extended to business application fields whose main characteristic for distributed systems integration. OGSA gives focus on grid services. All grid resources in OGSA are abstracted into grid services, and uses grid services as uniform software entries to provide sharing interfaces, which can shield the heterogeneity of grid resources effectively. On the Grid Computing environment, geospatial information users can not only gain distributed services of geodata and geoprocessing, but also rent computing resources, storage resources, etc. The direct effect is from GIS application to geospatial information service based on the Grid, namely Grid Geospatial Information Service (Grid GIService). Grid GIService is an innovative theory and technology architecture changing the design and application patterns of GIS. It provides geospatial information users with the feasible idea and solution to capture, access, share, analyze, and process geodata for geospatial information application requirements.GIS interoperability is a hot research topic of GIS field in the 19th century, which is emerged under the conditions of distributed computing and heterogeneous geospatial databases and generally divided into two basic levels: data interoperability and functionality interoperability. On the Grid Computing environment, the key issue of Grid GIService is still interoperability. Grid GIService decomposes GIS functions according to given standards into functionality components, and then encapsulates them into various geospatial grid services with geoprocessing functions, i.e. Geospatial Atomic Services and their combination. So Geospatial Atomic Service is the core research content of Grid GIService. And Grid GIService turns its interoperability issue into the interoperability issue between Geospatial Atomic Services.This thesis does research on Geospatial Atomic Services, data interoperability and functionality interoperability of Grid GIService. The main contributions can be summarized as following:1. Grid GIService is a methodology designing, developing, managing, deploying, and maintaining geospatial grid services including Geospatial Atomic Services and Geospatial Combination Services, and also a technology architecture capturing, transmitting, storing,managing, analyzing, processing, and visualizing geospatial data, information, and knowledge.2. This thesis proposes a service-oriented architecture based on OGSA for Grid GIService. The architecture is composed of five logical layers from bottom to top: Resource Layer, Basic Service Layer, Metaservice Layer, Service Layer, and Application Layer, and can reflect Geospatial Atomic Services is the core topic and data and functionality interoperability are the key issue of Grid GIService.3. This thesis systemically studies the interoperability framework of Geospatial Atomic Services, including service classification, service framework and interoperability protocol stack. In terms of the geoprocessing functionality, Geospatial Atomic Services are divided into six top-level categories: Human Interaction, Formation Management, Workflow, Processing, Communication, and System Management Service. Each category is divides into some sub category. The Geospatial Atomic Services Framework provides a common set of interfaces, interchange protocols, and Geospatial Atomic Services, including Client Services, Registry Services, Service Metadata, Processing Service, Portrayal Services, and Data Services. Interoperability protocol stack is based on Web Services protocol stack. It describes the interoperability layers and standards, Quality of Service (QoS) Specifications.4. This thesis establishes a Petri net-based model for Geospatial Atomic Services combination based on the analysis of the actuality and existing problems on service combination. In the model, it is straightforward to map a combination service into a Petri net system (Place/Transition system). The atomic services invoked by the combination service are modeled by transitions and the state of the combination service is modeled by places. Resources flowing between places and transitions are the massages and the data in the combination service, and the arrows between places and transitions are used to represent the flowing direction of resources. The combination of Geospatial Atomic Services is divided into four basic patterns: sequence combination, choice combination, parallel combination, and iteration combination pattern. The four basic service combination patterns can be nested in a variety of ways to express various complicated service combination. This thesis presents the Petri net-based graphic and semantic expression of the four basic patterns, and describes four basic service combination operators and their algebraic properties. The Petri net-based model for service combination has the characteristics as following; establishing an uniform high-level model which can express existing various service combination patterns; distinctly describing the collaboration relation between atomic services invoked by the combination service; optimizing the design of service combination using the graphic expression based on Petri net and the algebraic properties of service combination operators.5. This thesis analyzes the three key problems on the data interoperability of Grid GIService:accessibility, availability, and attainability about geospatial data, and puts forward a service-oriented data interoperability architecture used as a effective solution to data interoperability of Grid GIService. The architecture is composed of four cooperative roles. Data Provider has the network-addressable geospatial data, and describes their geospatial metadata to publish into Geospatial Metadata Catalogue Service that is responsible for managing and maintaining the geospatial metadata. Data Requester finds desired geospatial data by Geospatial Metadata Catalogue Service, and then accesses and integrates the distributed the geospatial data using grid data services provided by Service Provider. Geospatial Metadata Catalogue Service based on Metadata Catalogue Service (MCS) uses Logical Dataset to replace Logical File in MCS and extend the objects of data management from file systems to database systems. A Logical Dataset may be a geodata file, a database, a map layer, and a relation datasheet, etc. The metadata schema is defined based on the core metadata of ISO/FDIS 19115. Data interoperability really takes place during the course of distributed geodata access and integration. This thesis puts forward a solution extending OGSA-DAI (Open Grid Services Architecture-Data Access and Integration) activity. The solution adds a geodata query activity in which a set of geodata query interfaces is defined. So the extended OGSA-DAI services can access and integrate distributed geodata.6. This thesis analyzes the three key problems on the functionality interoperability of Grid GIService: accessibility, availability, and attainability about geospatial grid services, and puts forward a service-oriented functionality interoperability architecture used as a effective solution to functionality interoperability of Grid GIService. This thesis analyzes the actuality and existing problems on metaservice and discusses the requirements of computing and data intensive applications for advanced metaservices such as route, recover, and switch. This thesis designs and implement a Metaservice Framework, which can provide not only basic metaservices (publish and find), but also advanced metaservices by monitoring the invocation and the execution between geospatial grid services. The functionality interoperability between geospatial grid services is implemented on based on Sample Object Access Protocol (SOAP). The key problem is how to exchange the complicated geodata between services. This thesis puts forward a geodata exchange solution based on SOAP messages. In the solution, geodata and its correlative attribute data are contained in SOAP Body in GML format, and the geospatial metadata is contained in SOAP Header in XML format.
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