Automatic 3D building reconstruction has becoming increasingly important for a number of applications. The reconstruction of buildings using only aerial images as data source has been proven to be a very difficult problem. The complexity of the reconstruction can be greatly reduced by combining the aerial images with other data sources. In this paper, we describe a 3D building reconstruction method that integrates the aerial image analysis with information from large-scale 2D Geographic Information System (GIS) databases and domain knowledge. By combining the images with GIS data, the specific strengths of both the images (high resolution, accuracy, and large-information content) and the GIS data (relatively simple interpretation) are exploited. D