Abstract: Disclosed herein are methods for decoding path data. The methods may comprise providing a navigation database for storing topological information of a road network. The navigation database comprises a plurality of road links, and a plurality of link nodes, each link node defining a topological connection between two or more of the road links. The methods may further comprise receiving path data indicative of a path within the road network, wherein the path data comprises a start identifier, a link count, and at least one exit number. The methods may further comprise selecting, from the navigation database, one road link of the plurality of the road links as a start road link of the path based the start identifier. Moreover, the methods may comprise iteratively expanding the path with selected road links until the link count is equal to the number of road links of the path.

Abstract: In one embodiment, an attribute application associates content with a road segment. In operation, the attribute application generates a spatial reference identifier based on coordinates associated with the attribute. The attribute application then generates an attribute based on the content and the spatial reference identifier. Finally, the attribute application transmits the road segment attribute to a navigation system that performs at least one navigation operation based on a road database and the attribute. Because the attribute is specified based on spatial referencing, the attribute application requires fewer resources to generate attributes than conventional approaches that generate different attributes for different versions and formats of road databases.

Abstract: In one embodiment, a match application identifies an edge corresponding to a road segment based on an observational point specifying an estimated position and an estimated heading. The match application performs search operations on a road network graph based on the estimated position to identify multiple candidate edges. For a first candidate edge, the match application computes a first quality level based on at least a distance between the estimated position and the first candidate edge and an angle between the estimated heading and a direction associated with the first candidate edge. Subsequently, the match application determines that the first quality level indicates that the first candidate edge has a higher quality than any other candidate edge. Finally, the match application transmits the first candidate edge to an application that associates content specified in relation to the estimated position with the first candidate edge.

Abstract: In one embodiment, a layer application generates navigation-related data based on observations associated with vehicles. In operation, the layer application generates an attribute based on a first observation associated with a vehicle and an observation type. The layer application then compares the attribute to an existing road database to generate a dynamic layer. Subsequently, the layer application causes the dynamic layer to be transmitted to a navigation subsystem. After receiving the dynamic layer, the navigation subsystem performs navigation operation(s) based on the road database and the dynamic layer. Because the layer application may receive and operate on real-time observations, providers of road databases may produce dynamic layers at a frequency that enables navigation applications to continually provide accurate navigation data.

Abstract: Disclosed herein are methods for decoding path data. The methods may comprise providing a navigation database for storing topological information of a road network. The navigation database comprises a plurality of road links, and a plurality of link nodes, each link node defining a topological connection between two or more of the road links. The methods may further comprise receiving path data indicative of a path within the road network, wherein the path data comprises a start identifier, a link count, and at least one exit number. The methods may further comprise selecting, from the navigation database, one road link of the plurality of the road links as a start road link of the path based the start identifier. Moreover, the methods may comprise iteratively expanding the path with selected road links until the link count is equal to the number of road links of the path.

Abstract: In one embodiment, a speed limit application associates speed limits with road segments based on a road graph. In operation, the speed limit application selects a source road segment that meets a target road segment at an intersection based on the road graph. The source road segment is associated with a speed limit. Subsequently, the speed limit application determines a confidence value associated with extrapolating the first speed limit to the target road segment based on the first road graph. The speed limit application then determines that the confidence value indicates that a confidence in the extrapolation satisfies a minimum confidence requirement. Consequently, the speed limit application generates an attribute that associates the first speed limit with the target road segment. Finally, the speed limit application causes a navigation-related operation to be performed based on the attribute.

Abstract: A system may generate a database of a geographical map of a navigation device. The geographical map covering a geographical area which is divided into several update regions. The system may identify at least one object in the geographical map which covers an object area in the geographical area. The object area can be divided into different parts which are located in different update regions. The system can store in the database, for each of said at least one object, information indicating that the object area overlaps with plural update regions, the information including pointers to update regions in which the respective different parts of the object area are stored.

Abstract: In one embodiment, a cluster application generates navigation-related data based on observations received from vehicles. In operation, the cluster application computes an oriented distance between two observed object positions based on a heading, where each observed object position is associated with a different one of two observations. The cluster application then generates a cluster that includes the two observations based on the oriented distance. Subsequently, the cluster application computes an object position that is associated with the cluster based on the two observations. The cluster application transmits the object position and at least one characteristic associated with the observations to a update application that generates an update to a road database. Because the cluster application computes the object position based on multiple observations that are likely of a single object, the object position associated with the cluster may be more reliable than the observed object positions.

Abstract: In one embodiment, a speed limit application associates speed limits with road segments based on a road graph. In operation, the speed limit application selects a source road segment that meets a target road segment at an intersection based on the road graph. The source road segment is associated with a speed limit. Subsequently, the speed limit application determines a confidence value associated with extrapolating the first speed limit to the target road segment based on the first road graph. The speed limit application then determines that the confidence value indicates that a confidence in the extrapolation satisfies a minimum confidence requirement. Consequently, the speed limit application generates an attribute that associates the first speed limit with the target road segment. Finally, the speed limit application causes a navigation-related operation to be performed based on the attribute.

Abstract: In one embodiment, an attribute application associates content with a road segment. In operation, the attribute application generates a spatial reference identifier based on coordinates associated with the attribute. The attribute application then generates an attribute based on the content and the spatial reference identifier. Finally, the attribute application transmits the road segment attribute to a navigation system that performs at least one navigation operation based on a road database and the attribute. Because the attribute is specified based on spatial referencing, the attribute application requires fewer resources to generate attributes than conventional approaches that generate different attributes for different versions and formats of road databases.

Abstract: In one embodiment, a cluster application generates navigation-related data based on observations received from vehicles. In operation, the cluster application computes an oriented distance between two observed object positions based on a heading, where each observed object position is associated with a different one of two observations. The cluster application then generates a cluster that includes the two observations based on the oriented distance. Subsequently, the cluster application computes an object position that is associated with the cluster based on the two observations. The cluster application transmits the object position and at least one characteristic associated with the observations to a update application that generates an update to a road database. Because the cluster application computes the object position based on multiple observations that are likely of a single object, the object position associated with the cluster may be more reliable than the observed object positions.

Abstract: In one embodiment, a layer application generates navigation-related data based on observations associated with vehicles. In operation, the layer application generates an attribute based on a first observation associated with a vehicle and an observation type. The layer application then compares the attribute to an existing road database to generate a dynamic layer. Subsequently, the layer application causes the dynamic layer to be transmitted to a navigation subsystem. After receiving the dynamic layer, the navigation subsystem performs navigation operation(s) based on the road database and the dynamic layer. Because the layer application may receive and operate on real-time observations, providers of road databases may produce dynamic layers at a frequency that enables navigation applications to continually provide accurate navigation data.

Abstract: In one embodiment, a match application identifies an edge corresponding to a road segment based on an observational point specifying an estimated position and an estimated heading. The match application performs search operations on a road network graph based on the estimated position to identify multiple candidate edges. For a first candidate edge, the match application computes a first quality level based on at least a distance between the estimated position and the first candidate edge and an angle between the estimated heading and a direction associated with the first candidate edge. Subsequently, the match application determines that the first quality level indicates that the first candidate edge has a higher quality than any other candidate edge. Finally, the match application transmits the first candidate edge to an application that associates content specified in relation to the estimated position with the first candidate edge.

Abstract: A navigation system has a database which stores index data for, respectively, a tile of a tiling. The index data includes, for each one of plural cells of a grid which is superimposed on the tile, respectively an identifier for each triangular face of a triangulated irregular network which at least partially overlaps with the respective cell. The plural cells of the grid are defined so as to cover the respective tile. A processing device of the navigation system is configured to use the index data to determine a triangular face on which a map feature having given lateral coordinates is located, in order to determine a height coordinate of the map feature.

Abstract: Techniques for displaying a 3d map view of a 3d geographical map are provided. A database stores data which defines the 3d geographical map in a layered hierarchy comprising data layers which can be individually rendered for the 3d map view. The database comprises a data layer of a digital terrain model which is modelling a terrain surface and a data layer of a 3d road network comprising 3d road elements. A processor is configured for selecting specific data layers of the database in response to a resolution setting of the 3d map view and to render the 3d map view using the selected specific data layer.

Abstract: A navigation system determines one or more routes for a user from one location to another. The navigation system uses model data or information about weather, date, or time to determine an optimal route for a user. The navigation system may consider user preferences and dangerous or awkward conditions or criteria, and may perform a cost value analysis in determining the optimal route for a user.

Abstract: Techniques for generating a 3-dimensional map view of a navigation system are disclosed. A position module determines a position of a user to which the 3-dimensional map view is to be displayed, a viewing direction and elevation for the user. A map viewer generates the 3-dimensional map view of the map data, wherein for objects located within a predefined distance to the position of the user the position and the representation of each object is calculated taking into account the viewing direction and the elevation, wherein for objects located outside the predefined distance at least one group of objects, to which the objects belong, is identified, and for each identified group the background image is selected and displayed in which the 3-dimensional objects of the identified group are shown from the determined viewing direction and elevation. A display device displays the generated map view.

Abstract: A database for a navigation system has digital elevation model data defining a three-dimensional surface. The database stores, for plural tiles of a tiling, a first array including three-dimensional coordinates of vertices of plural triangulated irregular networks, TINs, for the respective tile, and a plurality of second arrays. Each second array respectively defines triangular faces of a TIN and includes a plurality of vertex indices of the vertices to define triangular faces of the respective TIN. A method of outputting a three-dimensional representation of a terrain and a method of generating the database are also described.

Abstract: A system for performing a similarity search in a navigation device data base uses a metric index structure. The index structure includes a plurality of nodes. When a query object is received, a node of the index structure which is associated with at least one object is accessed. A distance between the query object and the at least one object is determined in accordance with a distance metric. Based on the determined distance, another node of the index structure is selectively accessed.

Abstract: A navigation device for a vehicle comprises a database storing, for a plurality of tiles of a tiling, at least one triangulated irregular network (TIN) defining a three-dimensional surface, and, for a plurality of triangular faces of the at least one TIN, control information defining a nested bounding sphere for the respective triangular faces. The navigation device comprises a processor coupled to the database configured to calculate a screen-space error for the plurality of triangular faces based on the respective control information and based on at least one of the following: a viewing angle of an electronic map view, a virtual camera position of the electronic map view. The processor is configured to predict whether a triangular face is visible in the electronic map view based on the calculated screen-space error.