目的 3维城市可视化是智慧城市信息显示的基础,对城市信息的实时准确传递起着重要作用。而现有的3维城市可视化方法和系统存在两点局限性:一是数据模型不适合于海量建筑物显示;二是对整个城市采用单一绘制方式,而建筑物的纹理、结构、高度等特征相似,绘制结果容易引起视觉混淆,为此提出一种基于人类感知理论的3维城市在线可视化技术。方法 在预处理阶段,系统采用建筑综合算法建立3维城市建筑物的多分辨率表示;在运行时刻,系统根据用户交互,自适应选择建筑物相应的层次进行显示。结果 采用几个3维城市数据对系统进行了测试,实验结果证明,该系统有效地提高了3维城市绘制效率。Leverkusen城市的5 530座建筑物,绘制效率达到19.4帧/s。结论 基于感知的3维城市多分辨率表示,有效提高了3维城市系统的显示效率以及用户获取信息的效率,同时提高了用户的交互效率。

Objective Three-dimensional (3D) city visualization is fundamental for information display in smarter cities. Existing 3D city visualization systems are mainly limited in two aspects. First, the data model of a 3D city is unsuitable for handling massive building data and does not support real-time network transmission. Second, given that the whole city is rendered in a homogeneous graphic style and that most buildings are highly similar in texture, structure, and height, the rendering results usually exhibit high visual complexity. In this study, we propose a technique for online 3D city visualization on the basis of human visual perception and spatial cognition theory. Method During preprocessing, our system creates a multiple representation of buildings on the basis of the building generalization technique. Then, at runtime, the system can dynamically choose an appropriate level of buildings on the basis of human interaction. Result The algorithm is tested on several large 3D city models. Experiment results confirm the applicability of our algorithm to interactive visualization and information intensity reduction of a 3D city. For the Leverkusen city model with 5 530 buidings, we have improred the frame rate to 19.4 frame/s. Conclusion The proposed method can improve the efficiency of 3D city rendering and thus enable users to obtain relevant information through efficient interaction.