The Three-dimensional Geographic Information System Research And Practice, The Relevant Technologies

As a marginal subject formed by some other subjects such as Geography, Surveying and Mapping, Graphics, Remote Sensing, Geography Information System (GIS) has become mature and is going forward to socialization. Three-dimension (3D) and dynamic GIS has become one of the pop problems in the research and application of GIS.This paper takes some research about 3D-GIS and its primary works are as follows:1. According to the way of spatial cognizance and the thought of Object Oriented, a new data structure for 3D-GIS is presented based on researching the existing data structures, which adopts a three-lay structure including the lay of fundament geometric model, the lay of appliance model and the lay of relation model. This data structure is fit for human thought, benefit to storage and management of spatial data and also benefit to spatial analysis in three-dimension space.2. The technology of three-dimension animation is researched in this paper, in which temporal characteristic of geographic data was explored mainly by using the technology. Meanwhile, practice was taken about three kinds of animation technology including camera animation, entity object animation and circumstance animation.3. The technology of mutual function between user and computer in 3D topography is studied, in which the strongpoint and shortcoming in the method of positive solution and the method of oppositive solution is analyzed and their improvement is also presented. At the same time, a method of their combination is presented which can improve the precision and the dependability of mutual function.4. The method of querying substance in 3D space is studied, in which the mechanism of pickup and feedback provided in OpenGL is discussed, and one method of querying substance by translating 3D into 2D +1D is presented and used in practice.5. Definition of collected class is used to present the topology among the objects in 3D space.6. Data structure in 3D community is studied and a new way to class substance on land is presented which takes full account of characters of display and combination of vector data and attribute data.7. A set of 3D visualization system is produced by virtue of visualized programme platform according to something in this paper. As well, one 3D terrain module in this system is used in a GIS project and makes good effect which proves the importance and practicability of this system to GIS.