A digital elevation model (DEM) is a digital representation of ground surface topography or terrain. It can be represented as a raster (a grid of squares) and it is commonly estimated by utilizing remote sensing techniques, or from land surveying. In this research a 3D building of Baghdad university campus have been performed using DEM, where the easting, northing, and elevation of 400 locations have been obtained by field survey using global positioning system (GPS). The image of the investigated area has been extracted from QuickBird satellite sensor (with spatial resolution of 0.6 m). This image has been geo-referenced by selecting ground control points of the GPS. The rectification is running, using 1st order polynomial transformation. Estimation of the ground layer elevation is carried out by spline and IDW interpolation, the buildings have been delineated as polygons with given real heights in the second layer. The mosaic algorithm has then been applied between the two layers to perform the final DEM creation process. Finally, the estimated DEM have been used to constructing 3-D building.
