3D GIS Study Of Water Conservancy

This paper sets focus on the 3D GIS study of water conservancy and demonstration of water conservancy spatial information in 3D is the goal. The 2D GIS has been widely used in such fields as water resource, transportation and construction. Compared with 2D GIS, 3D GIS is endowed with the following peculiarity: It is stronger in expressing the real world model; It exhibits the geographic spatial objects using the technique of solid sculpt; It can demonstrate both the spatial relationship and the characteristics of spatial objects.The emphasis of this paper falls on two categories: 3D GIS modeling of water conservancy and 3D GIS data structure. Meanwhile, technique of 3D visualization, display of DEM, spatial analysis in 3D GIS of water conservancy are also discussed. The technical routine of this paper can be described as this: According to the mechanism of GIS information handling the whole domain of water conservancy is classified into four levels, which are water conservancy hinge, water project, water conservancy building and water conservancy cell. By the classification mentioned above water conservancy can be disassembled and assembled spatially. What's more, 3D GIS data model and data structure is constructed taking the lowest level as the primary element.The production of this paper is what is targeted initially: 3D GIS data model and data structure of water conservancy. The 3D GIS data model is like this: water conservancy cell is defined as the first level which is used to assemble the higher level objects and the cell itself can be generalized as the single geometries like column, taper, sphere and so on; Then comes the second level of water conservancy building that is assembled by a series of objects of the first level; Using the same method, the third level of water conservancy project and the fourth level of water conservancy hinge are assembled. If a series of water conservancy hinges are grouped, the fifth level of water conservancy group is on hand. Therefore, the 3D GIS data model of water conservancy can be extended.The 3D GIS data structure of water conservancy can include the followinginformation of water conservancy object: generalization, geometry, position, spatial, logical, visualization and the water conservancy features. It can also be extended if necessary. When assemblage is in process, on one hand, the to be objects of higher level will inherit the features of the being assembled objects of lower level; on the other, the assembled higher-level object will take on some new features.