Research And Implementation Of 3D Visualization Of Geologic Map

With the development of VISC, GIS, VR, geoscience maps are becoming digital, three-dimensional and interactive. Geologic map is an indispensable tool for geologist's work. But it can't express 3D space information of geologic elements, just as a kind of 2D ichnography. So there is important significance to study the 3D visualization of geologic map and its correlative functions.The 3D visualization of terrain is the premise for the 3D visualization of geologic map. So the author puts forward a multi-resolution model based on block quad tree to implement the 3D visualization of terrain. This model breaks the restricts of the height and width of the entire grid height data field and broadens its applying scope. Meanwhile it adopts observation error evaluation criteria to improve error test, and uses recursive activation methods to eliminate crevices, which consumedly improve the executive efficiency of arithmetic and speed up the visualization of terrain.A significant function of the 3D visualization of geologic map is the production of the cutting section. For this purpose, the author brings forward a production model of the cutting section, which can basically produce the cutting section of any site on any direction on a 3D geologic map. At the same time, the author adopts raster assistance algorithm and intersection algorithm of Line segments with local space transform to improve the intersection process of the cutting section, which directly speeds up the producing of the cutting section.At last, the author develops a 3D visualization system of geologic map on the basis of Visual C++ and OpenGL, and tries it out in the north of Honggouzi area and the west of Lingjiaqiao area, which has made achieved better results.