Abstract: In order to better meet the demand of automatically determining the precise eave height of buildings in the construction of Smart City models, a method of initial eave height determination is proposed based on the maximum edge information, Edge Images, and 2D DLG (digital line graph) overlays of the position of eaves, to determine precise eave height through generalized point photogrammetry iteration. Experiments show that this method delivers eave height automatically for buildings in 2D DLG, with a decimeter accuracy. It provides a method for 3D DLG production, and contributes to the development and progress of technologies such as 3D building reconstruction, and automatic man-made objects extraction.