基于表面剖分的3DCM空间数据模型研究

A 3DCM Data Model Based on Surface Partition

3维城市模型 (3 DCM)的研究近年来得到了飞速发展 ,但目前所开发的 3 DCM系统大多属于 3维可视化系统 ,所提供的空间分析与操作功能极为有限 ,究其原因 ,主要是缺乏能有效表达城市 3维实体及其空间关系的 3 DCM空间数据模型。尽管在 3 DGIS数据模型的研究方面 ,许多学者提出了很有价值的模型 ,但这些模型均难以满足城市 3维建模的要求。针对这一问题 ,本文首先分析了城市 3维实体的几何特征及 3 DCM系统要求 ,提出用外表面表示体状实体 ,以便用 TIN对面状和与体状实体进行统一表达 ,在此基础上就可采用单纯形作为 3维实体的基本要素 ,从而归纳导出了基于表面剖分的 3 DCM空间数据模型。作者还以简单建筑物、复杂建筑物、立交桥为例 ,对折面实体、曲面实体和复杂实体的表面剖分与表达进行了研究 ,并开发了实验系统 ,以实例论证了该模型的可行性。

The research about 3DCM is in full swing, and also got a rapid progress in recent years. But the majority of the 3DCM systems are only 3D visualizing systems, which have few functions to provide operation and analysis, and it's also difficult to represent complex 3D objects. The main reason is that its spatial data model can't represent 3D objects and spatial relationships between them efficiently. As traditional 3D GIS data model seldom considers the idiographic feature of 3D objects and 3DCM system itself, the present 3D GIS data model can't be used in 3DCM, so it's need to establish a data model especially for 3DCM. Because the representation of Face objects and Body object is the key problem, this paper introduces to settle this problem by TIN partition representation to these objects surface, and from this main view point, a 3DCM data model based on Surface Partition is put forward. In addition, we explored an experiment system and construct many 3D entities, with these entities we illustrate the data model in detail.