The Vehicle-borne Laser Measurement System (VLMS) is a mobile mapping system where three single-row laser range scanners, six line CCD cameras, and a GPS/INS-based navigation unit are mounted on a van to measure object geometry and texture along a street. This paper contributes to a method of fusing the data output of VLMS with existing geographic data sources where the focus is on the rectification of the vehicle's motion data derived from GPS/INS, which may be quite erroneous in an urban area. An algorithm is developed to correct the four variables of the vehicle's motion data, i. e., x, y, and z coordinates of the vehicle position and yaw angle of orientation by registering the laser points of the VLMS with an existing data source, e. g., a DSM. The algorithm was examined using the VLMS data that were taken in the Ginza District, Tokyo. By manually assigning 18 sets of tiepoints, the vehicle's motion data were corrected automatically and efficiently, such that the laser points of VLMS were matched to a DSM. In data fusion, a set of objects, which contained commercial signboards, traffic signs and signals, road boundaries, and road lights were extracted from the corrected VLMS data using an interface described in a previous paper. They were integrated with a 1:2500 3D map that consists of only building frames. In addition, line images from the VLMS were projected onto the building facades of the 3D map, and textures were generated automatically.