Tom Tom International B.v.

Tomtom Traffic B.v.

Lars Petzold

Sven Baselau

Ralf-Peter Schaefer

Axel Berndt

A method of encoding a continuous path within a road network is described, the path being completely represented within a digital map and expressible as a path list of lines and/or segments existing in said digital map and consecutively ordered, wherein said lines and/or segments have one or more attributes associated therewith. The method involves storing a start position in a route search list, and determining a path from the start node of the start position and including said start position to an end node of the last line or segment in the path list within said digital map. The path is determined according to an algorithm utilizing an attribute of said lines or segments. The attribute may be a lowest functional road class (LFRC) of the path to be encoded or a part thereof.

Efficient location referencing method

A method, of resolving a location from an ordered list of location reference points being representative of nodes in an encoder digital map and each having attributes representative of a specific line or segment in the encoder digital map emanating from or incident at those nodes, is disclosed. In at least one embodiment, the method includes (i) for each location reference point, identifying at least one candidate node existing in a second digital map, and, using the available attributes of that location reference point, identifying at least one candidate line or segment existing in the second digital map emanating from or incident at the candidate node, (ii) performing a route search within the second digital map between: (a) at least one of said at least one candidate node and the corresponding candidate line or segment emanating therefrom or incident thereat, and (b) at least one of a candidate node for the next location reference point appearing in the list and the corresponding candidate line or segment emanating therefrom or incident thereat, and extracting from the second digital map each line or segment forming part of the route so determined between the candidate nodes, (iii) repeating step (ii) for each consecutive pair of location reference points up to and including the final location reference point appearing in the list. Preferably, the route search is a shortest path route search, most preferably operating on respective pairs of successive candidate nodes, and includes a way of ensuring that the corresponding line or segment of the first of the pair of nodes forms part of the route resulting therefrom.

Method of resolving a location from encoded data representative thereof

A efficient method of encoding a continuous path within a road network in which the path to be encoded is expressible as a path list of lines and/or segments existing in a digital map and consecutively ordered. The method comprises the steps of: (i) storing a start position in a route search list; (ii) determining a path from a start node of the start position and including said start position to an end node of the last line or segment in the path list within said digital map, said path being determined according to a shortest path algorithm; (iii) comparing the shortest path so determined to the path list, and identifying at least one deviation line or segment being part of the path list and having a start node representative of an intersection in said digital map but not being the line or segment first appearing in said path list, and if such deviation line or segment does not terminate at the end node of the last line or segment appearing in the path list, repeating step (i) using said deviation line or segment; and (iv) storing the last line or segment in the path list in said route search list if not already stored.

Growing community of inventors

Berlin, Germany

Lars Petzold