Patent ID: 8977480
Filing Date: 2015-03-10
Classification: G01C,G08G

Abstract:
1. A method for determining barrier crossing information using historic trajectory data, said method comprising the steps of: receiving trajectory data representative of the movements of a plurality of objects over a network of travel paths with respect to time, said trajectory data for an object comprising a plurality of sequential time-stamped geo-positions, and said network of travel paths comprising at least one barrier crossing which periodically impedes or restricts the free flow of objects along the network of travel paths; associating the received trajectory data with segments of a digital map, said segments being representative of the network of travel paths; determining the trajectory density along at least some of the segments as a function of position and time from the trajectory data, the trajectory density being indicative of the number of objects at a particular location and time; identifying locations at which the trajectory density changes periodically from zero to substantially greater than zero; using a frequency distribution for the trajectory density changes at said identified locations to determine the location of a barrier crossing and augmenting the digital map with the determined location of the barrier crossing, the barrier crossing being between a first segment and a second segment; determining at least one of a crossing timetable or crossing frequency for the barrier crossing from the changes in trajectory density; and associating the determined at least one of the crossing timetable or crossing frequency with the barrier crossing in the digital map.