Based On The Vc And Opengl Overpass Visualization

The Three-Dimensional Geographic Information System(3DGIS) is one of the development trends of current GIS research field and research focuses. With the space degree form two-dimensional to rise to three-dimension, it has a series of questions along with it to urgently to be solved. For example, the three-dimension data modal of object, the management and visible of the three-dimension data model and so on. 3DGIS underwent more than nearly ten years of development, these problems have been solved to a certain extent, but realization still has a great deal of problems to the complicated target's three-dimension realization in 3DGIS category of studying fictitiously. For example, the three-dimension fictitiously realization of complex cloverleaf junction in Transportation Information System. Present thesis's core content is the data modal and the visible technology of three-dimension object. Through regarding XiaoCaiyuan cloverleaf junction as the embodiment, author gathers field data, processes data , discusses the three-dimension model and to Three-Dimension visual realizes, proposes one feasible method of three-dimensional reconstruction of cloverleaf junction.This thesis reviewed the three -dimension Geographic Information System's present situation and the development tendency at first, and explained the meaning of the selected title of this research. Because the three-dimensional data model is the foundation of 3DGIS system, it concerns directly what models are set up is good and bad. This thesis has carried on detailed analysis to compare to the setting-up algorithms of several kinds of main three-dimensional models. Because visual technology of three-dimension object is the indispensable part in 3DGIS system. This text has carried on detailed exposition to OpenGL technology adopted in case study too. On the basis of summarizing and analyzing that studies progress in three-dimensional data model at present, it has proposed a makes the three-dimensional modeling method up on the basis of the character of cloverleaf junction. The author has mainly made the following progress while studying.1. Collected data. Do control measure and detail measure with total station.2. Use a kind of improved Delaunay triangular network algorithm to set up irregular triangular network (TIN) model to road and topography, use border of road and topographical border to restrain it.3. Set up cloverleaf junction model according to the thought of assembling object.4. Use OpenGL figure storehouse to realize the three-dimension reveals.5. Realize some space analyzing and inquiring on the basis of the three-dimensional model.