Abstract: A system and method are disclosed that provide traffic information to end users. The traffic information is contained in traffic data messages that use location reference codes to identify locations along roads. A data structure is formed that relates a set of location reference codes assigned to locations along roads by a first data supplier to another set of location reference codes assigned locations along roads by a second data supplier. The data structure is used to form traffic data messages containing location reference codes assigned by the first data supplier based on traffic data messages containing location reference codes assigned by the second data supplier.

Abstract: A method and system for use by driver assistance systems installed in a motor vehicle to continuously provide such systems with updated data about paths along roads onto which the motor vehicle can travel from a current position of the motor vehicle as the motor vehicle travels along said roads. The method includes accessing a database that contains data that represents segments of roads and intersections of a road network located in a geographic region in which the motor vehicle is traveling and determining one or more paths along roads onto which the motor vehicle can travel from a current position of the motor vehicle. Each path is extended out to a threshold. Data representing each of the paths is provided in an organized data structure for use by the driver assistance systems.

Abstract: The Hough Transform is used to identify the circular arcs and straight line segments that coincide with the horizontal curves of roads. The Hough Transform uses data indicating positions along the roads as an input in order to identify the circular arcs and straight line segments that coincide with the roads. Data indicating the circular arcs and straight line segments are stored in a geographic database and are used to represent the roads. Radius of curvature of the road is obtained as a by product of this representation. Because the Hough Transform yields a closed form representation of road segments, the heading at any point along a road can be computed by computing the tangent to the closed form representation. Thus, heading can be accurately obtained at any point along a road.

Abstract: A method for comparing geometric shapes to each other is disclosed. The method includes determination of a rotational variation metric. The shapes to be compared are scaled so that their lengths are equal and tangent vectors at corresponding locations along the geometric shapes are determined. The angle between each pair of corresponding tangent vectors for each of these locations is then plotted as a function of the length along the geometric shapes. The variation around the mean angle between the tangent vectors for the locations along the geometric shapes being compared is the rotational variation coefficient. This process defines a rotational variation metric which indicates how closely the two geometric shapes match. The rotational variation metric can be used in various geographic applications, including vehicle positioning, sign recognition, and evaluating geographic database accuracy.

Abstract: A navigation method and system are disclosed whereby users of the systems are provided with backup driving instructions. A wireless communications system allows end users' computing devices to receive dynamic route guidance from a remotely located navigation services provider. The dynamic route guidance provides each end user with maneuvering instructions at appropriate locations along a route to a desired destination. In addition to the dynamic route guidance, the navigation service provider also provides the end users with backup driving instruction data. The backup driving instruction data can be used by an end user's computing device to provide backup driving instructions for traveling to the destination. The backup driving instruction data can be used in case wireless communications is interrupted.

Abstract: A reporting program and system whereby end users of navigation systems, or other computing platforms that use geographic data to obtain navigation-related or map-related services, can make reports about the geographic data. The reporting program can be used by end users to report perceived errors or inaccuracies in the geographic data. The end users can use their own personal computers, or other computing devices, to access the reporting program over a network, such as the Internet. When an end user accesses the reporting program, the reporting program provides a graphical map image to the end user on the end user's computing platform. The reporting program allows the end user to zoom and pan the graphical map image in order to display an image of the area about which the end user wishes to make a report.

Abstract: The bearing of a road segment indicates the direction that the segment follows from an end thereof. A primary bearing of a road segment is determined with respect to a significant shape point located along the road segment. The significant shape point is not necessarily the shape point closest to the end point, but is that shape point located within or beyond a predetermined range of distance from the end point. A secondary bearing is determined for some road segments. The secondary bearing indicates the general direction that a road segment follows leading away from an end point. The secondary bearing is determined using a view distance. The view distance is based on attributes of the road segment and represents an estimate of the distance of the driver's field of view as he/she approaches the intersection. Data indicating the primary and secondary bearing can be stored in a geographic database used by a navigation system.

Abstract: A navigation system includes a computing platform that has geographic data and navigation applications installed locally. Use of the computing platform is monitored and reported via a wireless communications system to a remotely located facility. The remotely located facility handles billing the end user based on use of the navigation system. The remotely located facility also transmits authorization back to the local computing platform to enable the end user to obtain requested navigation services.

Abstract: A system and method are disclosed that make operation of an emergency vehicle safer. When an emergency vehicle is traveling to or from an emergency, a route for the emergency vehicle to travel is calculated using a navigation system. Traffic signals along the calculated route are controlled to give the emergency vehicle the right-of-way along the calculated route. In addition, data indicating the calculated route of the emergency vehicle are transmitted to other vehicles located along the calculated route. In each of these other vehicles, warnings are provided to the vehicle drivers. These warnings indicate the presence of the emergency vehicle and optionally, the expected path of travel of the emergency vehicle.

Abstract: A system and method for providing geographic data to end users' computing platforms. A server maintains downloadable geographic data that are organized into pre-computed parcels that correspond to pre-determined sub-areas into which the entire geographic region serviced by the server is divided. The server responds to requests from the end users' computing platforms for navigation services and data by sending selected pre-computed parcels of geographic data to the end users' computing platforms. The end users' computing platforms store the pre-computed parcels received from the server in a cache memory. The end users' computing platforms use the data in the pre-computed parcels to provide navigation-related features locally.

Abstract: A data collection system including a data glove is used by a researcher to safely and efficiently collect and input data for a geographic database. The data collection system is transported by the researcher along roads in a geographic area. As the data collection system is being transported, the positions of the data collection system are determined. The researcher inputs data into the data collection system through the glove by hand and/or finger gestures. The data collection system stores data indicating a determined position with a type of data associated with the gestures. The data obtained by the data collection system is displayed so that the researcher can add or modify data records in the geographic database. The data obtained by the data collection system is used to add data to or modify data in the geographic database.

Abstract: The degree to which a linearly extending feature, such as a road, curves is indicated using a bowing coefficient. The bowing coefficient at a given location along a linearly extending feature is determined by comparing the distance along the feature between two points on either side of the given location (or an approximation of the distance) to a straight-line distance between these same two points. Bowing coefficient data can be used by various vehicle systems that require information about the curvature of linearly extending features, such as roads upon which the vehicle is traveling.

Abstract: A program and method for route calculation for use with a navigation system and used with a map database that represents a road network in a geographic region. A route calculation program is adapted to find at least one solution route between a first location on a road network and a second location on the road network. The route calculation program includes a first search tree associated with the first location and a second search tree associated with the second location. Each search tree is adapted to hold gates. Each of the gates represents a physical position on the road network and a direction from the position to another location along a path on the road network. The route calculation program also includes at least one priority queue associated with one of the search trees. The priority queue assigns a priority to one of the gates in the associated search tree based upon an evaluation using a search algorithm.

Abstract: A computing architecture for a motorized land-based vehicle is disclosed. The computing architecture includes a data network comprised of a plurality of interconnected processors, a first group of sensors responsive to environmental conditions around the vehicle, a second group of sensors responsive to the vehicle's hardware systems, and a map database containing data that represent geographic features in the geographic area around the vehicle. A vehicle-environment modeling program, executed on the data network, uses the outputs from the first and second groups of sensors and the map database to provide and continuously update a data model that represents the vehicle and the environmental around the vehicle, including geographic features, conditions, structures, objects and obstacles around the vehicle. Vehicle operations programming applications, executed on the data network, use the data model to determine desired vehicle operation in the context of the vehicle's environment.

Abstract: A process and system for collecting data about roads located in a geographic area and using the collected data to develop representations of the locations and geometry of the roads for a geographic database. A vehicle in which data acquisition equipment is installed is driven on the roads. Using the data acquisition equipment, data are collected representing positions of the vehicle as it is being driven along the roads and data indicating the path of the vehicle as it is being driven along the roads. The data acquired while traveling may be smoothed and fused. The data acquired while traveling are processed by a program that automatically selects which of the data are necessary to provide a specified level of accuracy in a geographic database that includes data that represent the roads including data that represent positions and geometry of the roads. The data selected by the program are stored in the geographic database.

Abstract: A feature provided by a navigation system or other device whereby additional information about roadside signs can be provided to a driver of a vehicle while travelling along a road. The additional information may be provided automatically or in response to a request from the driver. The additional information may include a translation of the sign text into a selected language, supplementary information about the subject matter of the sign, commercial information about the subject matter of the sign, or other kinds of information. In one embodiment, the additional information is contained in a database that includes data identifying locations of roadside signs and additional information about the roadside signs. Programming in the navigation system or other device determines the location of the vehicle, uses the database to identify one or more roadside signs close to the location of the vehicle, and provides the driver with the additional information about the one or more roadside signs via a user interface.

Abstract: A method for displaying a zooming operation on a display screen of a computing platform. The method includes retrieving data from a geographic data storage system, possibly located on another system, displaying a starting image that shows geographic features at a first scale with a first level of detail and then displaying an ending image that shows the same geographic features at a second scale with a second level of detail. Between the displaying of the starting image and the displaying of the ending image, at least one intermediate image is displayed. The intermediate image combines two component images of at least some of the same geographic features shown in the starting or ending image. The two component images in the intermediate image are at the same scale and are registered with respect to each other so that the same geographic features represented in the two component images coincide.

Abstract: A system and method for collecting address data for a geographic database are disclosed. Data are collected using a plurality of end users' navigation systems. The data indicate a location at which a trip by a vehicle in which a navigation system is located ended and a desired destination entered into the navigation system by an end user prior thereto. These data are received in a data collection facility that statistically analyzes the data and uses the data to update a geographic database.

Abstract: A method of determining geographic feature association between geographic features of a first geographic database and a second geographic database builds a proximity matrix having a proximity value element for each of the features of the first geographic database as compared to each of the features of the second geographic database. A singular value decomposition of the proximity matrix is computed, and the singular value decomposition is converted into an association matrix. Using the association matrix, the method identifies an associated feature pair having one feature of the first geographic database and one feature of the second geographic database.

Abstract: A vehicle positioning application in a navigation system provides for determining a change of vehicle heading using differential wheel speed sensors and compensates for dynamic and static changes in the wheel radii.