| In this paper, from the view of development and application of two-dimensional GIS and three-dimensional GIS, discuss the common features and shortcomings of several models in two three-dimensional integrated GIS. It proposes a number of issues need to be resolved, including rendering interfaces, spatial coordinates and vector-grid integration. This paper focus on the map projection and coordinate system, multi-scale vector data on the sphere of expression, vector data in the symbolic by three-dimensional API and do some systemic analysis, discussion and testing. It completes the major work:1. Through analyzing the concept of map projection in the plane model, sums up some limitations in the map projection and flat map reference system, proposes new ideas that vector data is visualized on the sphere based on the geographical spherical or ellipsoidal surface of the geographical space, ensuring large-scale vector data in the expression of continuity and consistency.2. It describes ways and meaning of Multi-scale vector data's expression, analyzes the common strategy to improve the rendering speed. In the case of cartographic generalization theory and technology having not fully mature, proposes the way of multi-scale expression based on multi-scale topographic map and achieving quickly expression and organization of multi-scale data in the three-dimensional space through multi-threading technology and memory pool.3. It briefly describes concepts and categories of Map symbols, analyzes respective characteristics and structure theory of point feature symbol, line feature symbol and area feature symbol, proposes and implements symbolic method in three-dimensional interfaces (OpenGL).4. From the point of view that the map display of expression and the amount of information contained, proposes selection method of electronic map elements based on the level of detail, this method is to set the LOD factor of map various elements and conclude closely related factors.
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