Abstract: A method for generating a compressed navigation map database from uncompressed navigation map data, wherein the uncompressed navigation map data contains different building blocks of navigation data, each building block addressing a functional aspect of the navigation data, each block containing strings of data. The method includes determining, for each block of the uncompressed navigation map data, most frequent substrings of the block; storing, for each block, the determined most frequent substrings of the block in a seed block; replacing, for each block, in the strings the determined most frequent substrings stored in the seed block by a reference to the seed block thereby generating a compressed block for each block; and storing, for each block, the compressed block and the seed block in order to generate the compressed navigation map database.

Abstract: A navigation device comprises a database storing footprint data for buildings which define a footprint of the respective building. For at least some buildings, the footprint data comprise position information defining a position of the building, a length indicator indicating a length of a rectangular portion of the footprint, and a width indicator indicating a width of the rectangular portion of the footprint. The length indicator is stored in a single byte. The width indicator is stored in another single byte.

Abstract: The invention relates to generating a three-dimensional (3D) graphical representation of a building. The method comprises establishing appearance control data comprising information on parameterized architectural features of the building and on building blocks which are fragments indicative of the building, and retrieving template data from a database based on references in the appearance control data, wherein the template data relates to a prefabricated graphical representation of the building blocks. The method further comprises, for each building block, calculating a 3D graphical representation of the building block based on the respective template data and the appearance control data, and combining the 3D graphical representations of the building blocks based on the appearance control data to generate the 3D graphical representation of the building.

Abstract: A navigation device comprises a processing device and a database. The database may store first data defining, for a plurality of objects, respectively a three-dimensional representation of the object. The database may store second data including, for at least a subset of the plurality of objects, an icon representation of the respective object, coordinates of the respective object and a pointer to a portion of the first data which is associated with the respective object. The processing device is coupled to the database and is configured to control an optical output device to display an object based on the first data or based on the second data.

Abstract: A navigation system (NS) may include a processor that can retrieve geographic map data from a database, where the geographic map data includes polygonal chains. The processor can determine a straightness value, a length ratio, and/or an angle-to-length ratio for each of the polygonal chains based on segments and/or vertices of the polygonal chain. Also, a first class and a second class of the polygonal chains can be determined based on one or more of the three determined values for each of the polygonal chains. The first class may represent roads that are less winding than the second class, and such an attribute may be beneficial in selecting an optimal route.

Abstract: The invention relates to system and method for generating a 3-dimensional representation of a tunnel. Road network data is provided having a plurality of road segments, at least one road segment being a tunnel road segment, including the information that said at least one road segment is a road segment located in a tunnel. The tunnel segment in the road network is identified, providing a geographical elevation map including elevation data of the geographical region in which the tunnel road segment is located, providing predefined patterns representing predefined parts of a 3-dimensional tunnel body, generating the 3-dimensional representation of the tunnel based on the tunnel road segment, the elevation map and the predefined patterns, and storing the 3-dimensional representation of the tunnel in connection with the road network as a 3-dimensional object which is located at the geographical position of the tunnel road segment.

Abstract: A method for generating a compressed navigation map database from uncompressed navigation map data, wherein the uncompressed navigation map data contains different building blocks of navigation data, each building block addressing a functional aspect of the navigation data, each block containing strings of data. The method includes determining, for each block of the uncompressed navigation map data, most frequent substrings of the block; storing, for each block, the determined most frequent substrings of the block in a seed block; replacing, for each block, in the strings the determined most frequent substrings stored in the seed block by a reference to the seed block thereby generating a compressed block for each block; and storing, for each block, the compressed block and the seed block in order to generate the compressed navigation map database.

Abstract: A navigation device comprises a processing device and a database. The database may store first data defining, for a plurality of objects, respectively a three-dimensional representation of the object. The database may store second data including, for at least a subset of the plurality of objects, an icon representation of the respective object, coordinates of the respective object and a pointer to a portion of the first data which is associated with the respective object. The processing device is coupled to the database and is configured to control an optical output device to display an object based on the first data or based on the second data.

Abstract: The invention relates to system and method for generating a 3-dimensional representation of a tunnel. Road network data is provided having a plurality of road segments, at least one road segment being a tunnel road segment, including the information that said at least one road segment is a road segment located in a tunnel. The tunnel segment in the road network is identified, providing a geographical elevation map including elevation data of the geographical region in which the tunnel road segment is located, providing predefined patterns representing predefined parts of a 3-dimensional tunnel body, generating the 3-dimensional representation of the tunnel based on the tunnel road segment, the elevation map and the predefined patterns, and storing the 3-dimensional representation of the tunnel in connection with the road network as a 3-dimensional object which is located at the geographical position of the tunnel road segment.