Studies Interactive Vectorization Methods Based Virtual Three-dimensional Terrain Surface

GIS data collection is a very time-consuming and expensive work, but it is one of the important tasks of the GIS. At present, the mainly methods of three-dimensional vector data capturing are ground-based measurements, GPS and photogrammetric. In recent years, the LaserAce Scanner for point cloud data has emerged as a new method for3D vector data acquisition. Due to efficiency issues, or because of costs, equipment, application features a range of issues, the application of those methods often limited to a particular area. In the field of earth science applications, the three-dimensional vector data usually has a specific significance in geoscience, which requires a new kind of three-dimensional vector data acquisition method, enabling geoscientists the flexible vector data acquisition and analysis. Based on this, we propose a the interactive vectorization method based on a virtual three-dimensional terrain surface using ordinary two-dimensional mouse interaction capture three-dimensional vector data, DEM-based3D visualization environment.First, sort out and analyze the relevant theories and technologies, including the basic principles and methods of three-dimensional terrain visualization, the basic principles and methods of three-dimensional interactive graphics and the GIS basic questions, provides a theoretical design of specific methods on guidance. Step-by-step the basic steps of the three-dimensional terrain analysis, highlights the biggest difference-three-dimensional display and two-dimensional display projection transformation, and analyzes the impact of this gives the three-dimensional vector of. Summarized and summary of the basic concepts and features of the three-dimensional interactive graphics, and made a brief introduction to learn commonly used in the field of visual interaction, interactive basic idea of the mainstream3D modeling software to do a rough summary, in order to be able to virtual three-dimensional terrain surface vector inspiration. Three-dimensional surface vector data collected from the DEM and three-dimensional surface vector data as digital control surface features discussed.Then, edit the line three-dimensional surface vector data collection methods, preliminary design. The characteristics of three-dimensional interactive design components of a "brush", multi-dimensional display window, and multi-positioning, visual interpretation of the three-dimensional environment uncertainty. Hierarchical property of the vector data, design layer management tools provide independent unit, three-dimensional vector editing and file management. Respectively three conceptual model of surface points in space, a method on the design of a three-dimensional curves and three-dimensional surface data model generation algorithm, as well as the editing process.Finally, preliminary realization of three-dimensional surface vector editing of the data collection method based on the IDL visualization of language, prove that this method is practical and feasible.