| 3D GIS is tightly tied in with VISC(Visualization in Science Computing), Mathimatics, Geo-science,etc. The thesis aims to make research into visualization technology of 3D GIS in geo-field, and to implement the case of study, Geothermal Water Spatial Information Management System of Fuzhou, which runs on Windows OS platform. The main tasks in research are listed as follows: According to the concept of 3D GIS, functional requirement in geo-field and structural demand of software, the conceptual model of 3D GIS in geo-field is builded. And all kinds of spatial data models which are the basis of algorithm on visualization are discussed. Volume visualization is a joint between VISC and 3D GIS, the prospect of which is summarized in this thesis. And two basic algorithm on visualization of 3D data are expounded: Surface-fitting method and Direct Volume Rendering(DVR). In the case of study, the better fittable algorithm of volume visualization is selected in accordance with the analysis of the software. We combine the algorithm of Ray Casting and Z-Buffer to rebuild 3D data, and use Marching Cubes to create Iso-surfaces in 3D regular Data Sets. Several common spatial interpolation are discussed in this thesis, and the famous Kriging algorithm in the geological statistics is the emphasis. - Four interpolations are used in the case of study, and the results are compared in this thesis. Based on the above relevant theories, the archetype, function modules and data models of the software are designed. The technical difficulties and theirs solutions are dwelled on. In the module of 3D Visualization, the flow of volume rendering is given: pretreatment of volume data -> data sorting -> illumination procession -> volume rendering. Shape Files, DXF files can be loaded in the software to provide the functions of spatial analysis.The case of study based on real 3D Geographical Coordinates has implemented, which is the leader of research on 3D GIS in the relevant field of china.
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