1. A method of identifying a trajectory of an object on a map, the trajectory being aligned with road segments in a road map network, said method comprising: identifying GPS shifting fields for at least two of the road segments with a GPS shifting field constructor, each GPS shifting field of the GPS shifting fields including an area around a road segment of the road segments that includes false GPS readings of objects that traveled on the road segment; revising the GPS shifting fields with the GPS shifting field constructor, the GPS shifting fields being revised with at least one of a road segment attribute and at a driver preference, the road segment attribute including at least one of a road segment name, locative information for the road segment name, and a popularity score for the road segment name, and the driver preference including at least one of a preferred road, an unpreferred road, a shortest route preference, a quickest route preference, and a no toll preference; partitioning the road map network into space units with a GPS shifting field indexer connected to the GPS shifting field constructor, the road map network including at least two GPS readings of the object; for each space unit that includes at least one road segment of the road segments, calculating for each road segment in the space unit with a virtual network constructor connected to the GPS shifting field indexer, a probability that the object was located on the road segment in the space unit based on the GPS readings of the object and the GPS shifting fields; and determining the trajectory of the object with a most possible path searcher connected to the virtual network constructor, the trajectory of the object being determined based on said computing of the probabilities.