| 摘要 |
A navigation device comprises a database storing data for reconstructing three-dimensional roof structures. The data includes information on edges (64, 65) of at least one closed polygon and a type identifier respectively stored in the database for each one of the edges (64, 65). Each one of the type identifiers is respectively selected from a finite set of type identifiers. Plural planar faces (55-56) are generated to reconstruct the roof structure. The planar faces (55, 56) are respectively determined such that they pass through an edge (64, 65) of the polygon and have an orientation determined based on the type identifier stored for the edge. |
