1. Field of Art
The present invention generally relates to updating databases of road map information that can be used for vehicle navigation or similar purposes.
2. Description of the Related Art
Digital databases of road map information are essential components of a variety of useful applications, such as vehicle routing. The road map information databases used in vehicle routing systems describe the layout and characteristics of the roads over which vehicles travel, such as the locations of various roads and their intersections, traffic speeds over the various road segments, and the like. The use of real-time location data, such as that provided by a satellite-based Global Positioning System (GPS), in conjunction with such databases allows a vehicle routing system to determine the location of a user's vehicle and to take actions useful to the user, such as suggesting directions to a desired destination from the current location. As the database information is augmented to describe additional characteristics of roads and traffic conditions, the applications using the database are thereby enabled to provide additional, more useful features. For example, the addition to a database of information regarding real-time traffic conditions enables a vehicle routing application to suggest not only a route that minimizes overall distance, but also one that minimizes driving time based on the current traffic speeds associated with the route.
However, databases frequently lack important categories of information that applications could use to provide more accurate results or entirely new categories of features. Some examples of information that is not generally available are the locations of stop signs and traffic lights, information about whether traffic lights are timed or untimed to coordinate with traffic flow, and information about the illegality of certain turns at certain times of day. As an example of the utility of such information, information about the illegality of certain turns at certain times of day could be used to detect that a route that was optimal at 11:00 AM would be entirely prohibited at 6:00 PM, thus avoiding proposing an invalid route to the user.
Of additional concern is the fact that database information may contain inaccuracies due to human error on the part of those creating the database, or due to failures to timely update the database to reflect actual changes in the roads themselves subsequent to the creation of the database. For example, a database may erroneously indicate that two road segments are disconnected when they are in fact connected, or vice-versa.
Some commentators have discussed the possibility of using in-vehicle GPS units to correct one of the deficiencies found in many databases—the lack of information on traffic speeds—by amalgamating the individual vehicle speeds recorded by GPS units over many vehicles to obtain statistical information about likely vehicle speeds on a particular road segment at a given time. However, there remain many other database information deficiencies for which no automated solutions have been discussed, although the need to address these deficiencies becomes ever more pressing as the number of related routing applications grows.