Vector data represents one major category of data managed by GIS. This paper presents a new technique for vector-data display that is able to precisely and efficiently map vector data on 3D objects such as digital terrain models. The technique allows the system to adapt the visual mapping to the context and user needs and enables users to interactively modify vector data through the visual representation. It represents a basic mechanism for GIS interface technology and facilitates the development of visual analysis and exploration tools. Categories and Subject Descriptors H.5.2 [Information Interfaces and Presentation]: User Interfaces - graphical user interfaces, screen design, interaction styles. I.3.3 [Computer Graphics]: Picture/Image Generation display algorithms, viewing algorithms. I.3.6 [Computer Graphics]: Methodology and Techniques - interaction techniques. I.3.7 [Computer Graphics]: Three-Dimensional Graphics and Realism - color, shading, shadowing, and texture. General Ter...