Method of generating a database for a navigation device

In a method of generating a database for use in outputting three-dimensional maps, a projection of a two-dimensional road vector onto a three-dimensional surface defined by digital terrain model data is determined. At least one three-dimensional road vector (94, 95, 98, 99) is determined based on the established projection and is stored in the database. The database is generated before it is deployed to a navigation device for use in outputting three-dimensional maps. A method of outputting three-dimensional maps and a navigation device may use the thus generated database.