Patent ID: 8170793

Claim:
A mapping system comprising a receiver and a sender arranged to communicate with one another via a communication link, wherein the sender includes an initial path definition defining a path, the initial path definition comprising: a starting point, a list of intersection points, and an end point; the sender further includes an encoder having means for encoding the initial path definition to a shortened path definition; the receiver includes a decoder having means for decoding the shortened path definition and means for reconstructing the initial path definition; and wherein the encoder further comprises: means for checking whether there is a valid alternate path between the starting point and successive points of the initial path definition, wherein the valid alternate path does not contain the part of the path between the last two points included in a check; means for completing the process of checking the initial path definition if there is no valid alternate path, and the means for checking has checked the path to the end point, means for eliminating the valid alternate path by adding a new routing point to the initial path definition, if a valid alternate path has been determined by the means for checking, means for repeatedly checking whether there is a valid alternate path between a newly added routing point and successive points of the initial path definition, wherein the valid alternate path does not contain the part of the path between the last two points included in a check, and means for completing the process of checking the initial path definition by defining the final shortened path definition as a starting point, a sequence of routing points, and an ending point of the path.