三维城市模型的统一表示

Unified representation of 3D city models

针对解决多维、多类型空间数据信息的透明集成管理与各种应用问题,在三维城市模型不同应用的分类和综合分析基础上,从概念层次提出了一种统一矢量数据与栅格数据、连续表面和离散实体的二维表达与三维表达的三维城市模型。该模型具备对任意复杂目标的多种细节层次表达和描述能力,为建立自动理解与解析分析的数学描述提供了理论依据。

For the purpose of integrated management and public application of 3D models under heterogeneous condition, this paper proposes a conceptual description of unified 3D city models based on classification of various applications and analysis of common requirements. Based on the study of different application characteristics of 3DCM, three different categories can be defined as： realistic visualization applications, 3D spatial searching and path navigation applications, and decision making support applications. Based on the cognitive theory, spatial phenomenon is classified into two types, feature entity and Fields. The point object, curve object, surface object, volume object, group object, LOD object, DEM and Texture object are then employed as the eight basic objects to describe urban spatial entities. The conceptual models can describe arbitrary complex objects with different levels of detail including raster objects, vector objects, continuous surface and discrete features. To ensure spatial consistency between 3D models at different scales, three special level-detail-of-relations between features and their geometry are defined as simple aggregation, hierarchy aggregation and hybrid hierarchy aggregation. The abstract model of 3D city is compatible with OGC specification, and is more easier to be extended to various cases. It provides theoretical proof for automatic data understanding and analysis. 2 figs, 13 refs.