Research On Three-Dimensional Spatial Data Models And Algorithms In Geology And Mine

The geographical information system (GIS) has provided the effective tools to capture, store, manage and analyze the spatial information. At present most commercial GIS software is based on 2D or 2.5D, which can not describe the real 3D spatial phenomenon effectively and efficiently. For the present, there are still a lot of problems that are unsolved or solved not so well, theoretically on 3D spatial data model and data structure, 3D data acquisition, storage and management of large volume data, modeling and analysis of 3D spatial objects and 3D visualization. As the core of 3D GIS, 3D data model decides directly the validity and capability of 3D GIS. Therefore, how to construct 3D data model is the key of 3D GIS research. 3D data model should varying with different thematic research domains because different characteristics of spatial objects should be involved in different domains and applications. The research of this dissertation focuses on 3D data model and algorithms of geology and mine. The main research works are as follows:(1) The concepts and terms of 3D spatial data model, the relation between spatial data model and spatial data structure are expatiated upon. By reviewing and classifying the current research situation of 3D spatial data models, the characteristics of all kinds of data model are summed up, and various common 3D spatial data models are carried out systematic comparison and analysis. The factors should be considered when designing 3D spatial data model are discussed.(2) Various natural geological phenomenon and artificial exploration engineering phenomenon in the research domain of geology and mine are analyzed systematically. The spatial dimension characteristic and geometric characteristic of various geological objects are expatiated upon, and the source, characteristic, classification and graphic expression of geological information are discussed. Considering the characteristic of uranium mine geological exploration engineering, the calculation principle and method of various feature points on borehole curve are explained in detail. The calculation formula of obtaining the 3D coordinates of feature point from profile chart is proposed.(3) The general framework of spatial data model integrated raster and vector is proposed, and the general framework classification system is study. For the purpose of researching on 3D spatial data model in geology and mine, an object-oriented conceptual data model based on Quasi Tri-Prism Volume (QTPV) is described using UML. A data model based on hybrid volume elements is put forward, and a hybrid data model based on multi-DEMs and QTPVs is also put forward.(4) The characteristics of 3D spatial model based on QTPV are analyzed and the definition of QTPV is proposed. The QTPV logical data model, data structure and topological relation among the model elements are designed. The algorithm of constructing QTPV model according to the real borehole sample data is proposed.Reasonable solutions to special problems, which appear during modeling stratum QTPV, are put forward. The QTPV modeling method of geological exploration engineering objects is discussed.(5) Various situation of QTPV is cut by a plane are studied, and the algorithm forming the profile chart after the QTPV model being cut by a plane is designed. The idea of QTPV partition into tetrahedron is put forward, and the partition forms, partition codes, partition code-vertex comparison table and partition algorithm are researched on. An algorithm of extracting TIN model from QTPV data model is proposed, and the modeling benefits of QTPV model are analyzed by comparing with 3D FDS and TEN.(6) The concept of the 3D stratum model based on multi-DEMs is discussed and the multi-DEMs conceptual model and data structures are designed. The idea of adopting five groups of topological relation tables to maintain four kinds of topological relation among the model entities is proposed. The existing modeling process of 3D stratum model is analyzed , and the concept of "Borehole-piece TIN Modeling method" is proposed and the work flow of constructing 3D stratum model is also designed. A model merge algorithm based on delaunay triangulation is proposed.(7) Based on grid index, a method of creating TIN model for stratum interface which constrained by feature lines is studied. For the description of different distributions of the data after an arbitrary plane cutting complex stratum model, an algorithm of creating TIN constrained by polygon data with islands which have a specific attribute is proposed. The dissertation also makes a research on triangulation algorithms in a simple polygon based on the dynamic identify of the minimum interior angle. Moreover, for modeling fault interface, the algorithm of minimum diagonal line is explored for the construction of serial triangle facets between two separate polylines.(8) For valuating the validity of 3D spatial data models and modeling algorithms proposed in this dissertation, two experimental prototype systems are developed on VC++ platform, and some real data is employed to verify the results of experiments.