Research On Mineral Resources Evaluation By Weights Of Evidence Model Based On Spatial Information Grid

Mineral resources evaluation is an important research item in the field of geology and mineral resources. It is a significant subject that improving the credibility, reliability of evaluation results and prospecting efficiency with computer technique. The application-oriented research on mineral resources evaluation by weights of evidence model based on Spatial Information Grid (SIG) is considered as two reasons: 1) Information island phenomenon appears because of Chinese geological changes in its operating system that geological data distributed in various regions and units that data are difficulty in sharing, and 2) There are large amounts of computation during the process of mineral resources evaluation. The assessment computing could not be completed on a high-performance server in a short period of time. SIG technology provides solutions to the problems above.Supported by the National High Technology Research and Development Program "Resources and Environment Information Sharing and Application Services based on Spatial Information Grid" (No.2002AA134010), the paper proposes the mineral resources evaluation by weights of evidence model based on spatial information grid and its application. The paper takes weights of evidence model as typical model, proposes the Mineral Resources Grid and its architecture and builds data integration platform, then develops mineral resources evaluation system based on SIG. Based on analyzing grid technology, Web Services Resources Framework and support of SOAP, WSDL, UDDI and XML standard agreement, it realizes the grid evaluation system based on Web services with Service-Virtualization and Service-Discovery mechanism.Mineral resources evaluation by weights of evidence model (WEM) is usually applied to evaluation on mineral resources. The paper describes the theory of mineral resources evaluation by WEM, including apdodty probability computing, weights of evidence computing, posterior probability and independence test. Based on the work steps and work flow of WEM based on GIS, it designs WEM web services, including apriority probability computing web service, weights of evidence computing web service, posterior probability web service and independence test web service, and gives the algorithm of web services and the sort of the component model, which are the foundation of mineral resources evaluation based on SIG.The paper introduces the concept of Grid, Grid GIS and SIG. It analyses in detail the agreement, role and life-cycle of Web services technology, which is one of the key technologies of SIG. Based on XML protocol, web services technology solves the problem that how to call grid services for evaluation system to satisfy the user's needs. And web service is the basic unit of SIG.Grid architecture is the framework of grid. The paper analyses three kinds of grid architectures, including protocol-oriented Five-Level Sandglass Architecture, service-oriented Open Grid Service Architecture and Web Services Resource Framework (WSRF), and discusses in detail the concept and service mechanism of WSRF. On the base of WSRF, the paper puts forward a 3-layer framework of assessment system by WEM based on SIG, including Data Service Layer, Data Processing Layer and Application Layer. According to 3-layer architecture, the evaluation method and work flow of mineral resources evaluation by WEM based on SIG are given.Service-oriented architecture is an approach to defining integration architectures based on the concept of a service. The paper puts forward the method to realize the mineral resources grid evaluation based on SOA. Based on Web Service-discovery mechanism, Web Services Register and Publication technology, it builds Web Service-Virtualization framework to realize distributed geospatial data integration and distributed computing function integration.In this paper, the author takes geospatial data analysis and integration application platform oriented resources integrating, resources sharing and application services as entrance for Internet users to request all kinds of mineral resources evaluation web services, which are designed as sets of public geospatial information services based on SIG that solve the problems of heterogeneous integration of geological data display and attribute extraction. Compensative processing flow based on web services is adopted by the modules of platform, such as the human-machine intercommunication interface processing flow and the component processing flow on system control.The mineral resources grid evaluation system by WEM is developed under the development environment of C# and.NET framework, based on the technology of MapGIS function library and SQL Server database. The evaluation system integrates heterogeneous data integration operation technology, geospatial data extraction technology and grid evaluation by WEM technology. And it realizes the mineral resources grid evaluation which is online, distributed and resources sharing. Evaluation gdd consists of Jiangsu grid node, Anhui grid node, Jiangxi grid node, Hubei grid node, Sichun grid node, Yunnan grid node, Xizang grid node and Beijing grid node. The evaluation method based on SIG has been applied in practical assessment which realizes acquiring, integrating, computing and analyzing geospatial data intellectively.The mineral resources grid evaluation system by WEM has been applied into the prediction of copper mineral occurrence in the Middle-Lower Yangtze Metallogenic Belt and the Three-river Metallogenic Belt, Southwest China. According to the posterior probability value of each geological element, also considering geological metallogenic laws, the author draw 56 copper mineral prognosis regions in the Middle-Lower Yangtze Metallogenic Belt, including 30 ore-prospective target regions of grade-A and 26 ore-prospective target regions of grade-B. Meanwhile, 18 typical modeling deposits are all in prognosis regions and some of prognosis regions are new. Geologists should pay more attention on these new prognosis regions. In the Three-river Metallogenic Belt, the author draw 12 copper mineral prognosis regions, including 5 ore-prospective target regions of grade-A and 7 ore-prospective target regions of grade-B. Assessment results passed the relative examination. It is proved that the structure, the grid evaluation model and evaluation method in this paper are practical and operative which can be applied in the field of mineral resources evaluation.At the beginning stage of research, there is no unified framework and technical specifications of Spatial Information Grid technology. It can combine with all the work in this dissertation represents certain use for reference to the research on mineral resources evaluation based on SIG which can be useful for relevant research.