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.

Abstract: A navigation system includes a driving profile program. The driving profile program collects information about an end user's driving activity. The information relates to trips made by the end user. The information includes departure times, intermediate stops, arrival times, purposes of the trips, and so on. After collecting this information over a period of time, the driving profile program analyzes the end user's driving activity. The driving profile program provides the end user with a driving activity profile. In addition, the driving profile program determines ways to reduce the amount of time and/or expense that the end user spends traveling in his/her vehicle and suggests modifications to the end user's driving activity that would save the end user time or expense.

Abstract: The invention provides a method and system for providing route guidance and other information from a base unit to a remote unit in response to a request from the remote unit. A query is formatted at the remote unit, the query including the request, and is transmitted from the remote unit to the base unit. Requested route guidance information is calculated at the base unit in response to the query, using a large up-to-date database located at the base unit. A response to the query is formatted at the base unit, the response including route guidance information. The response is then transmitted from the base unit to the remote unit for display. The transmission is made in a compact form through the use of maneuver arms and combined maneuver arms and through the use of tokenized forms. A maneuver arm represents a road at an intersection, for depiction on a display, by one or two endpoint coordinates.

Abstract: System and method are provided for route calculation for use with a navigation system and used with a map database with attributed no-outlet and circular segments. A route calculation program adapted to find at least one solution route, between a first location and a second location on a road network, identifies a segment with a first node and a second node in the road network. From an attribute stored in the map database, the program determines whether the first node is connected to the road network and the second node is connected to an isolated portion of the road network. Using the attribute, the route calculation program determines whether to explore the isolated portion of the road network. In some instances, the program refrains from exploring the segment leading into the isolated portion of the road network and the isolated portion of the road network itself.

Abstract: A data compression method and system that include the substitution of a substring of data characters located at a first position in a stream of data characters with a substitution code. The substitution code includes a reference to a previous position in the stream of data characters at which is located a substring of data characters that matches the substring of data characters which are being substituted located at the first position. The substitution code also includes an indication of the size of the substituted substring. The reference in the substitution code is a backwards offset to the previous position relative to the first position. According to a further aspect, Huffman encoding can be applied to the backward offsets, the substring lengths, the consecutive literal character lengths, and the literal characters themselves to reduce the data requirement size.

Abstract: A database architecture for using geographic data to provide navigation-related functions is disclosed. The navigation-related functions are provided by navigation program applications. A geographic database is stored on a medium and includes data representing geographic features and has a plurality of indexes into the data. A data access layer accepts requests from the navigation program applications for geographically-referenced data, accesses the geographic database and provides responses to the requests from the navigation program applications for geographically-referenced data. Logic rules are associated with the geographic database. The data access layer includes a deductive database engine that accesses and combines the logic rules to determine how to use to the indexes to access the data from the medium and to convert the data from a format in which they are stored on the medium into a format that the navigation program applications can use.

Abstract: A method implemented on a navigation system in a vehicle for determining the position of the vehicle relative to a road network. The navigation system uses a geographic database that contains data that represent positions of roads upon which the vehicle travels. Using the output from a GPS system, and optionally outputs from other sensors, the navigation system matches the positions of the vehicle to the locations of the roads represented by the data contained in the geographic database. Upon detecting an event from which the position of the vehicle with respect to the roads represented by the data contained in the geographic database can be determined with a relatively high degree of accuracy, a correction factor is determined. The correction factor is an offset (i.e., a distance and direction) of the GPS position reported during the event to the known-to-be-highly-accurate position. The correction factor is then used to adjust subsequently obtained GPS readings for a limited period of time, i.e.