Legend Symbol Data Model And Its Application Of Geological Map

In the geological maps, symbols are very important information. Unified, normative, and standard legend symbols are in favor of information exchange and sharing, which provides a solid foundation for the cluster, industrialization geological data information services. At present, in the actual process of producing geological maps, often also need to artificially geological elements to each entity to enter various symbols primitive parameters, surface rendering edit and modify information, this manual process is not only very cumbersome, but also prone to error. Currently there is a gap in the application of standards of geology and mineral industry such as "Regional Geological Map Legends, compared to basic geographic industry and farmland industry, which has not been able to satisfy the need of mineral resource potential evaluation for actual work. This is mainly because the current field in geological deposits is still lack of comprehensive symbol data model, let alone supporting software tool and application services based on the model. So there is an urgent need for researching the relationship between the attributes of feature and characteristic symbols in the geological maps, expanding and improving the existing standard geological legend symbol, establishing the legend symbol data model of geological map, developing in-depth research based on the model, giving apposite values of geological map and database.National mineral resources potential evaluation project (NMRPEP) is one of the largest basic census work since the founding of new China in geological and mineral industry. In the implementation process of NMRPEP, there have emerged many new theories, new technologies and new methods. In order to ensure the final project data usefulness, usability and accessibility, the project has formed a set of normative mineral resources potential evaluation data model in the early implementation stage, and produced results data based on the model. This paper uses the results map as data base, by analyzing the data in the legend symbol usage, puts forward a set of technical process and method of subclass symbol extraction, normalization and modeling, which tries to establish symbol data model of geological map.The main works done in this article are:(1) Analysis of the domestic and foreign research status of geological mineral database, database model, geological maps and standard, indicating that there is a larger gap in the field of research and application of the data mining model about the elements of legend symbols and other fields.(2) Analysis of the data compositions, data structures and data models of NMRPEP data maps. In-depth study of the professional pedigree and potential evaluation data classification and coding system characteristics, by clarifying the composition of the logical relationship between the data model and a variety of coding standards, combined with the existing geological maps of the elements of a standard classification system, designing the content of symbol data model for symbol professional pedigree, symbol logic code and symbol physics code. By studying the division of a subclass, this paper specifies the meaning of the symbol data model is to find out the relationship between the symbol subclass, feature properties and legend symbols.(3) The data-driven and knowledge driven general idea of combining as a guide, designed and implemented from symbol sub class division, the symbol parameter extraction process to the symbol data model storage. The physical storage of data model is using the legend symbol data dictionary, combining MapGIS secondary development components to complete a series of software tools of subclass division, symbol automatic parameter extraction, and legend symbol modeling tool, using ADO large-field technology to save and call the picture of symbol.(4) Carried out application research of the legend symbol data model, designed and implemented the report generation tools, the legend board mapping function and the symbol standardizing function based on standardized legend symbol data model. The results show that the established legend symbol data model is simple structured, clear logic, with complete content, which can meet the function realization.The ultimate goal of this paper is to develop a set of comprehensive legend symbol data model in the field of Geology and mineral resources. It not only can be used in the NMRPEP, in the other major projects based on similar geology data model, such as the "National Crisis Mines Resource Prospecting Project","National Mineral Resource Utilization Survey Project", also has some reference and promotional value.