Visualizations and simulations in an urban environment need 3D digital maps rather than traditional 2D maps, and constructing 3D maps from multiple data sources has become a promising and challenging research area nowadays. In this paper, we propose a method for modeling roads, buildings, and ground from 2D digital maps and Laser Range Finder(LRF) data. Firstly, road surfaces are created through extracting road region on the input 2D map and elevating their vertexes by using LRF points inside the road region. Secondly, building's boundaries in the 2D map are modeled to cubes whose base and roof elevations are calculated from near LRF points. The ground is represented by Triangular Irregular Network(T1N)based surfaces created from road boundaries, building's base boundaries, and flat area in LRF data. Some experiments are also carried out to illustrate the effectiveness of the proposed method. 1 Instructions GIS(Geographic Information Systems) is capable of assembling, storin...