Abstract: At least one example embodiment discloses a method of detecting a bifurcation in a navigable feature. The method includes first determining a first possible segment and a second possible segment of the navigable feature based on location measurements along the navigable feature, the location measurements representing a heading vector and the location measurements having a higher probability of being on the first possible segment than on the second possible segment, second determining an angle based on the heading vector and a vector between the second possible segment and one of the location measurements, and detecting a bifurcation based on the angle.

Abstract: A navigation device comprising a receiver for receiving signals from position sensors, memory having stored therein a seed position and map data which comprises a map of navigable routes in an area, and an output device, such as a display or speaker, for outputting a current location. The navigation device further comprises a processor for determining distance travelled and changes in orientation from the signals and estimating the current location on one of the navigable routes of the map data. The step of estimating comprises using the distance travelled and the changes in orientation to extrapolate from the seed position possible paths along the navigable routes that the navigation device may have travelled and assigning to each path a probability that the navigation device travelled that path. For changes in orientation, the processor expands each path and recalculates the probability that the navigation device travelled that path.

Abstract: A computerised method is disclosed of creating map data from position data derived from the positions of at least one vehicle over a period of time, the map data including a plurality of navigable segments representing segments of a navigable route in the area covered by the map and the map data also including intersections between navigable segments representing intersections in the navigable route. In at least one embodiment, the method includes using a processing circuitry to perform the following: i. processing the position data; ii. calculating from the processing of the position data a transit time or set of transit times for at least some of the intersections in the map data; and iii generating further map data, which for at least some of the intersections therein, contains the calculated transit time or set of transit times associated with the intersection for which the calculation was made.

Abstract: A method and apparatus are described for rendering a display image generated from digital map information. The method includes the steps of: determining elevation information (20a) from the digital map information; determining display scale information (28) for the display image; and determining (22) a shading value to apply to a pixel in the display image, and applying the shading value to the respective pixel in the display image, to generate a display (24) that represents elevation information by pixel shading. The shading value varies as a function of the elevation information and the display scale information, whereby the display is generated to represent elevation information by pixel shading that varies with display scale.

Abstract: This invention relates to a data processing method for pixels (7) of a field of view (5), wherein the field of view comprises a portion of a digital map (1) that is to be displayed and includes a plurality of pixels (7), the digital map (1) comprises a plurality of data patches (3) which each include at least one data point, and the field of view (5) includes a plurality of said data patches (3), the method being characterised by: (i) identifying (504), for a said pixel (7), a data patch (3) in which said pixel (7) lies; (ii) locating (506-512) a border (9) of said data patch (3) that lies within said field of view (5); (iii) processing (522) all pixels (7) of said field of view (5) that lie within said border (9) to provide a processed data patch; (iv) locating (504-512), for each of any unprocessed data patches (3) within the field of view (5) that are adjacent a border (9) of a processed data patch, a border (9) of the unprocessed data patch (3) that lies within said field of view (5); (v) processing (522)