The Study And Experiment For Expression Method Of3D Geographic Information Symbolization

At the Smart City Stage, it requires the building of3DGIS much faster, more efficient and lower cost.3DGIS symbolization is an effective means to meet this requirement. It is one way to achieve the standardization and normalization of geographic information systems. It is in favor of building a unified spatial and temporal information cloud platform at smart city stage.The main contents of this paper include the following aspects:1. This paper summarizes the recent research about3D geographic information symbolization and introduces its premise as well as necessity, generalizes and summarizes the key issues that3D geographic information symbolization faced and proposes the corresponding solutions in the first part. Main content and the organizational structure are also included in this paper.2. In the second section, introduce the main technology which is used to realize three-dimensional geographic information symbolization, including the expression system of geographical elements in the urban scene, the principles of three-dimensional symbol design, the classification of symbolic elements, and parametric modeling technology. According to the3D Model and product specification, I divide the three-dimensional symbol into three parts, which include geographical elements, digital elements and finishing elements. Summary of the design principles and symbol visual variables, the classification of three dimensional symbols based on its content and spatial distribution, the theory of parametric modeling and related technology are also introduced in this paper.3. This part introduces the approach and technology to achieve the3D symbolization for all kinds of three-dimensional elements which expression of point features and discretization, linear features loft modeling, texture filled and random discretized of area features, and annotation features. According to key technologies, based on OSG and the classification of geography elements, realized in point, line, area symbols library. 4. Lastly, implement a three-dimensional GIS symbolic engine based on the designed OSG, and integrate three-dimensional symbol library, scene rendering module, data manipulation module and spatial analysis module to an ActiveX. Secondary development of engine platform for3DGIS symbolic system achieve2D vector data build three-dimensional GIS integrated management systemfast and automatic.