Abstract: A method and apparatus are provided for estimating an impedance through a node at an intersection between roads in a roadway network. The impedance may be measured in time or distance, for example. Characteristic information describes at least one feature of the intersecting roads. One or more pieces of characteristic information may impact the impedance of traffic through an intersection and are used to estimate the impedance through the node. Examples of characteristic information are speed information, road-type, network routing level, intersection angle information, one-way, and cross traffic turn information. An impedance factor, or a cost, is assigned to each piece of characteristic information. The cost may be positive if the characteristic information adds impedance to the node, or negative if the characteristic information subtracts impedance from the node.

Abstract: A method and apparatus are provided for estimating an impedance through a node at an intersection between roads in a roadway network. The impedance may be measured in time or distance, for example. Characteristic information describes at least one feature of the intersecting roads. One or more pieces of characteristic information may impact the impedance of traffic through an intersection and are used to estimate the impedance through the node. Examples of characteristic information are speed information, road-type, network routing level, intersection angle information, one-way, and cross traffic turn information. An impedance factor, or a cost, is assigned to each piece of characteristic information. The cost may be positive if the characteristic information adds impedance to the node, or negative if the characteristic information subtracts impedance from the node.

Abstract: A method and apparatus are provided for calculating potential paths between source and destination locations. First and second map databases are provided that are indicative of roadway networks for geographic regions bounded by region edges and containing source and destination locations. The first and second map databases are non-adjacent, non-contiguous such that the region edges of the first map database are separate and distinct from region edges of the second map database. Potential paths are calculated through the roadway network of the first map database up to a node or segment at which each potential path intersects a region edge of the first map database, thereby defining a node/edge coordinate. A transition location is obtained in the second map database that geographically corresponds to the node/edge coordinate at which a given potential path intersected the region edge of the first map database.

Abstract: A method and apparatus are provided for estimating an impedance through a node at an intersection between roads in a roadway network. The impedance may be measured in time or distance, for example. Characteristic information describes at least one feature of the intersecting roads. One or more pieces of characteristic information may impact the impedance of traffic through an intersection and are used to estimate the impedance through the node. Examples of characteristic information are speed information, road-type, network routing level, intersection angle information, one-way, and cross traffic turn information. An impedance factor, or a cost, is assigned to each piece of characteristic information. The cost may be positive if the characteristic information adds impedance to the node, or negative if the characteristic information subtracts impedance from the node.

Abstract: Systems, devices and methods are provided for more efficient use of RAM and other resources in connection with a route calculation algorithm which quickly obtains a best or reasonable best path between two locations. The navigational aid device includes forced layer switching capabilities. The navigational aid device includes a processor and a memory adapted to communicate with the processor. The memory has cartographic data including any number of locations and data indicative of thoroughfares of a plurality of types connecting certain ones of the locations. The plurality of thoroughfares are organized in a hierarchy of detail levels. The processor operates on a route calculation algorithm to find a path between any two of the number of locations and the route calculation algorithm dynamically forces switching between different levels in the hierarchy of detail levels based on a set of criteria.