中文摘要：

三维数字城市模型中地上下三维模型的数据种类复杂，多种数据的自适应性剪切技术是个难，苣。依据各种GIS三维模型的特点，定义地理和地质实体的语义模型，并针对不同对象使用基于空间分区二叉树（BSP树）的剪切算法，自适应地完成了数字城市地上下集成数据模型的一体化剪切和拓扑重建。最后结合南京市三维数字城市示范区地上下模型数据进行了应用试验分析，验证了该方法的有效性和实用性。

英文摘要：

The data about surface and underground models in a 3D digital city system are varied and quite complicated, which results in the difficulty of adaptive-cutting technology on a variety of data. According to the characteristics of these 3D GIS models, a semantic model of geographical and geological entities is defined in this paper. Using binary space partitioning （BSP）-tree cutting algorithm directed at different kinds of objects, integration cutting and topology reconstruction about surface and underground data model of a city are completed adaptively. Application test analysis is carried out upon the surface and under- ground model data of the 3D digital city demonstration areas in Nanjing city, confirming the availability and practicability of this technology.