GB2449128A - Contour sensitive navigation apparatus and method in a vehicle - Google Patents

Abstract

In a method and apparatus for navigating, mapping data is provided that includes geographical mapping point data with altitude information. A user is able to select a journey from a geographical start point to a geographical end point and to select at least one desired gradient parameter for the journey. At least one route is computed from the geographical start point to the geographical end point dependent upon the desired gradient parameters and the mapping data. The computed routing(s) can then be presented to the user. The accompanying figure shows an example method of selecting routing parameters.

Description

CONTOUR SENSITIVE NAVIGATION APPARATUS AND METHOD

BACKGROUND

S The present invention relates to a navigation apparatus, for example a vehicle navigation apparatus that can provide contour sensitive routing and to a method of providing contour sensitive routing.

Navigation apparatus is known, for example a vehicle navigation apparatus that can provide routing information based, for example, on satellite positioning information, for example GPS, Galileo, GLONASS or similar systems.

A known navigation apparatus can calculate a route from a start location to a destination using map data stored in the system and can provide guidance to a user by a visual display and/or by audible instructions. Some systems can calculate both a shortest route and a quickest route for the user to choose. If a user deviates from a pre-calculated route some systems automatically recalculate the route to the destination taking account of the deviation.

Routing, especially but not exclusively, in off-road situations, does not traditionally take account of a vehicles ability to successftilly handle steep. gradients or a user's desire or ability to handle such gradients, for example in adverse conditions.

Japanese patent application 2005-265464 describes the use of map data based on nodes arranged to correspond to intersections points of a lattice where a road does not exist. A link is defined between nodes to identify passable zones between the nodes, whereby impassable zones (e.g., an impassable river) can be avoided when computing a potential navigational routing due to the absence of a link between the nodes.

Japanese patent application 08-247777 describes a navigation apparatus in which a mean gradient of a route and mean and maximum gradients of ascent and descent can be computed and displayed based on altitude information.

However, there is a need to provide an improved navigation apparatus that can take account of a vehicles ability to successfully handle steep gradients or a user's desire or ability to handle such gradients, for example in adverse conditions, in a more flexible and efficient manner.

SUMMARY

An embodiment of the invention can provide a navigation apparatus comprising mapping data storage for mapping data including geographical mapping point data, the geographical mapping point data including altitude information. A user can select a journey from a geographical start point to a geographical end point and at least one desired gradient parameter for the journey. At least one route can be computed from the start point to the end point dependent upon the desired gradient parameters and the mapping data. The computed routing(s) can then be presented to the user.

When computing a routing, gradients can be computed from the altitude information of the geographical points and the gradients can be compared to the selected gradient parameter(s). Alternatively, or in addition, the gradients can be stored as part of the mapping data. One or more routings can therefore be computed that take account of the input gradient parameter(s), The gradient parameters can be selected by the user from one or more sets of options, for example including one or more of a set of minimum gradients and a set of maximum gradients.

In an example embodiment, a user can also select a maximum deviation from a direct routing and this can be used with the gradient parameter(s) when computing a routing.

In one example the navigation apparatus is a vehicle navigation apparatus.

An embodiment of the invention can also provide a vehicle comprising such a navigation apparatus.

An embodiment of the invention can also provide a method for navigating using a navigation apparatus, the method comprising the navigation apparatus: providing mapping data including geographical mapping point data with altitude information; enabling a user to select a journey from a geographical start point to a geographical end point and to select at least one desired gradient parameter for the journey; computing at least one route from the geographical start point to the geographical end point dependent upon the desired gradient parameters and the mapping data; and presenting to the user the computed routing(s).

In one example embodiment, a computer program product can include program instructions for causing a programmable navigation apparatus to carry out such a method.

Although various aspects of the invention are set out in the accompanying independent claims, other aspects of the invention include any combination of features from the described embodiments and/or the accompanying dependent claims with the features of the independent claims, and not solely the combinations explicitly set out in the accompanying claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the invention will now be described by way of example only with reference to the accompanying drawings.

Figure 1 is a schematic representation of a vehicle; Figure 2 is a schematic representation of a dashboard of a vehicle; Figure 3 is a schematic representation of functional elements of a navigation system for implementing the present invention; Figure 4 is a schematic representation of alternative routings up an incline; Figure 5 is a representation of a presentation of alternative gradient parameters; Figure 6 is a representation of a presentation of alternative route deviations; Figure 7 is a flow diagram of an example method of selecting routing parameters; Figure 8 is a schematic representation of geographical points data with gradient data for vectors between the geographical points; Figure 9 is a flow diagram illustrating an example of a method of computing one or more routings; Figure 10 is a schematic representation of alternative routings computed based on input gradient parameters; and Figure 11 is a schematic representation of further alternative routings computed based on input gradient parameters.

While the invention is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and are 25. herein described in detail. It should be understood, however, that drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the invention is to cover all modifications, equivalents and alternatives falling within the scope of the present invention as defined by the appended claims.

DETAILED DESCRIPTION

Example embodiments of the invention are described with reference to the accompanying draings. An embodiment of the invention can provide a method and an apparatus for navigating in which a user is able to select a journey from a geographical start point to a geographical end point and to select at least one desired gradient parameter for the journey. At least one route can then be computed from the geographical start point to the geographical end point dependent upon the desired gradient parameters and mapping data that includes geographical mapping point data with altitude information. The computed routing(s) can then be presented to the user.

Figure 1 a schematic representation of a vehicle 10 provided with a satellite antenna 12 for receiving satellite signals for use in a navigation system.

Figure 2 is a schematic representation of a dashboard 20 of a vehicle such as the vehicle I. Among other components illustrated on the dashboard are a display screen 22 of a navigation system, one or user operable controls 23 such as a touch screen facility for the display 22 and/or one or more control knobs, buttons, etc., a microphone 52 and a loudspeaker 54. These components will be referred to in the

following description.

Figure 3 is a schematic representation of an example of a vehicle navigation apparatus that is connected to the antenna 12 for receiving signals from a constellation of satellites of a global positioning system such as, for example a global navigation satellite system (e.g., the Global Positioning System (GPS) or the Galileo system). A positioning system 42 in the navigation apparatus processes the received signals and provides position signals representing the position of the navigation apparatus to a processor 46. Some, or all, of the processing of the signals may be done in the processor 46 instead of in the positioning system 42. The processor 46 may be a programmable microprocessor, microcontroller, other programmable processing unit or may be special purpose hardware or a combination of special purpose hardware and a programmable processing device or any other suitable processing apparatus.

Storage 44 stores a database contaimng mapping data from which a route may be calculated. In an example embodiment of the invention, the mapping data includes geographical point data including altitude data. In addition, gradient data in respect of vectors between the geographical point data can be stored. The storage may be any suitable type of memory, for example a non-volatile random access memory such as a flash memory, hard disk drive storage, etc. A memory 48 stores programs and other information for use by the processor 46. The memory 48 may be any type of suitable memory. Programs and other data may also, or alternatively, be stored in the store 44.

An output device such as, for example, the display screen 22 illustrated in Figure 2, which can, for example be an LCD display screen, can present visual information to the user. Alternatively, or in addition, an output device can be in the form of a loudspeaker such as the loudspeaker 54 illustrated in Figure 2 that can be used to present audible (e.g. voiced) information to the user from a voice command generator. The voice command generator can be implemented, for example, in software running on the processor 46 or could be implemented by special purpose hardware (not shown).

An input device 23 can be formed by one or more manually operable devices such as a control knob, switch, etc. that can allow the user to manually input data into the system and to select options presented to the user. Alternatively, or in addition, an input device can be implemented using a touch sensitive screen (e.g., incorporated in the screen 22) on which buttons can be displayed and operated. Alternatively, or in addition, the input device can include a microphone 52 which may be used in conjunction with a speech recognition system to input data and selections into the system. The voice recognition system can be implemented, for example, in software running on the processor 46 or could be implemented by special purpose hardware (not shown).

The processor 46 may also receive other data from components andlor sensors of the vehicle for example for detecting speed of travel andlor distance travelled for the purpose of improving the accuracy of the estimate of position especially in circumstances when it is not possible to receive sufficient signals from the satellites.

The programs and map data stored in the memory 48 and storage 44 can be operable to cause the processor 46 to operate in accordance with, for example, the flow charts of Figures 7 and 9 described hereinafter.

Figure 4 is a schematic representation of alternative routings for a journey from a start point 66 at the bottom of a hill 60 to a finish, or end, point 68 at the top of the hill 60. A direct routing 62 follows the shortest route from the start point 66 to the end point 68. However, given that there is a difference in altitude between the start point 66 and the end point 68, the shortest, or most direct, route 62 will mean that the incline to be overcome may be steep. An alternative, indirect, route 64 shows an indirect zigzag path which goes from the start point 66 to the end point 68. Although this indirect route is longer than the direct route 62, the indirect route 64 has a lower average steepness due to being longer. However, merely taking a longer route up the hill 60 does not mean that the steepness at any particular point on the route is less than the routing 62. For example, in any terrain, there may be steeper portions and less steep portions, whereby the choice of a correct route can be very important to enable a user to navigate from a start point without encountering excessively steep gradients.

Conventional routing, especially in off-road situations, does not generally take account of a vehicle's ability to successftilly handle steep gradients and/or the desire of a user to test their driving skill on steep gradients. The choice of a particular routing on an off-road situation is not a simple matter. The requirements for the choice of the routing can depend on particular circumstances. For example, an off-road driver may wish to have flexibility to alter the off-road route depending on weather conditions *, 9 and/or the vehicle status and/or a particular vehicle task at a given time. A user may wish to test their skill on steep gradients, or to avoid steep gradients, or to choose gradients within a particular range. An embodiment of the invention can enable a user to alter the route to suit his or her needs whereby an embodiment of the invention can provide a user-configurable setting to enable a navigation system to control its route calculation based on topographical data.

Figure 5 represents a presentation 70, for example on the display 22 illustrated in Figure 2, of a set of minimum gradients 72 and a set of maximum gradients 74. The presentation of the minimum and maximum gradients can, as will be described later, be used by the user to select a desired range of gradients for a route from a start point to an end point. The gradient can be described to the user either as portion (1:4, or "1 in 411) or as a percentage (25%).

The user may also wish to set an allowed deviation from a direct, or straight-line, route from the start point 66 to the end point 68. Figure 6 illustrates a presentation 76, for example on the display 22 illustrated in Figure 2, of allowed deviations from a straight-line route. This can be illustrated, for example, at 77 in terms of an overall range, e.g., small, medium, large, or in terms of a distance, for example one mile, five miles, ten miles, whereby the deviation could equally be indicated in terms of metres or kilometres. Also, the deviation from a straight-line or direct route can be expressed in relative terms, for example with a fixed percentage for each class, as opposed to being represented as a distance.

Figure 7 is a flow diagram illustrating one example of a method using presentations as illustrated in Figures 5 and 6, to enable a user to specify a desired minimum and maximum gradient for selecting one or more routes, and also to select a desired deviation from a straight-line or direct route.

In the example method illustrated in Figure 7, at step 80 the start and end points of the journey are determined. The determination of the start and end points of the journey can be effected by direct user input, in a conventional manner using the user input devices in combination with the output devices under the control of the processor 46 and information stored in the storage 44 andlor the memory 48.

Alternatively, the start point of a journey can be determined to be the current position of a vehicle as determined by the positioning system 42 illustrated in Figure 3.

In the example method illustrated in Figure 7, in step 82, the processor 46 can then cause maximum and/or minimum gradients to be presented to the user, for example as illustrated in Figure 5 using the display 22.

The user can then make a selection from either the set of minimum gradients 72 or from the set of maximum gradients 74 using the user input devices.

In step 84, the processor 46, in response to the selection of one of the minimum gradients 72 or one of the maximum gradients 74, can present the user with a list of available second selections, for example on the display 22, to enable a range of gradients from a minimum gradient to a maximum gradient to be determined. In other words, if the user had selected a particular maximum gradient (e.g., 1:4), then the possible minimum gradients (i.e., that are less steep than 1:4), could be presented to the user (e.g., by greying out the maximum gradients and greying out the gradients which are greater than 1:4, namely 1:2).

In step 86, in response to the user's selection of the second gradient value (say minimum gradient 1:12), the processor 46 can be operable to cause the presentation of the options for choosing an allowed deviation from a straight-line route, for example by displaying information as illustrated in Figure 6 on the display 22.

In response to the user's selection of an allowed deviation value (eg, small), the processor 46 can be operable to compute possible routings from the start position 66 to the end position 88 using topographical map data held in the storage 44 and/or the memory 48.

If, in step 90, it is determined that the processor 46 computed at least one valid route in step 88, then in step 92, the processor can cause the available valid routes to be presented to the user for selection (e.g., using the display 22). Where many possible routes are available to the user, the processor 46 can be operable to present the routes which best match the selected gradient range to the user.

If it is determined in step 90 that no valid routes were computed in step 88, then in step 94 the user can be informed that no available routes exist.

In the above-referenced process, the presentation of the options for selection by the user can be, for example, on the display 22. Alternatively, or in addition, the options for selection could be presented audibly (eg, by being voiced) by the navigation system 40. The user's selection of the navigation parameters can be effected by means of the user operable controls 23 (eg, the touch sensitive part of the display screen 22 or separate control knobs, switches, etc). Alternatively, or in addition, the user's selection can be made using a voice recognition system detecting the voice of the user using the microphone 52.

It should be appreciated that the method illustrated in Figure 7 is only one possible method for the user input of the navigation parameters. In the example shown in Figure 7, the start and end points of the journey are determined prior to entering the navigation parameters relating to the gradients and the allowed deviation. In another example, the gradients and the allowed deviation could be input prior to the selection of a particular journey, whereby the user could make a preselection of the navigation routing parameters before choosing a particular journey. Also, as illustrated in Figure 7, the selection of the gradients is performed before the selection of the allowed deviation. Clearly, the order of this selection could be reversed. Also, in a further embodiment of the invention, the user may be required only to input the gradients, whereby the allowed deviation is either pre-programmed, or not used. As a further alternative, rather than displaying both the minimum gradient options and the maximum gradient options at one time, the user could be presented firstly with the minimum gradient options and then with the maximum gradient options, or vice versa.

For example, the user could be required to select a maximum gradient first, and then to select a minimum gradient. Further, rather than the user having to select both a minimum gradient and a maximum gradient, the user could be required to select a single parameter (for example, being representative of a pre-programmed range of gradients of types such as easy, medium, difficult) whereby the system is pre-programmed to interpret a range of gradients meeting the basic gradient parameter. As a further alternative, rather than displaying individual values which can be selected, the user could be provided with a scale, whereby a position on the scale could be selected (e.g. using a rotary or slider control), this latter approach providing a continuous, rather than a discreet, selection of the gradient and/or deviation values.

Figure 8 is a schematic representation of one example of the storage of topographical mapping data in an off-road navigation situation. As illustrated in Figure 8, a matrix 100 of geographical points, or nodes, is stored, with, at each node 102, an altitude value representative of the altitude of the geographical position represented by the point or node 102. In order to improve calculation speed, the altitude measurement can be quantized.

As also illustrated in Figure 8, each of a plurality of vectors joining the nodes can have, associated therewith, a gradient measurement for the link represented by the vector. Once again, the link values can be quantized to improve data storage. As illustrated in Figure 8, a quantization of one percentage point is employed. However, in another example, another quantization can be used, for example 2.5 percentage points (eg, 10%, 12.5%, 15%, 17.5% instead of all available values in the range).

Optionally, the gradient measurement may represent all gradient measurements below 5% with a single value of 5%. In one example of the invention, the gradient values are used when computing a routing. In an alternative embodiment, the gradient values can be calculated directly from the altitude values. In such an example, the additional storage of the gradient values in the matrix 100 is optional.

Figure 9 is a flow diagram illustrating an example of the calculation of possible routings corresponding to step 88 of the flow diagram of Figure 7. 0 13

In step 112, a grid size is determined, whereby the X grid access is defined by the straight-line difference squared multiplied by a stretch factor, and the Y grid access is defined by a straight-line difference squared multiplied by the stretch factor. The stretch factor in the present example can be, for example a value from 0 to 2 determined by default or by the user's selection of a deviation (eg, a percentage deviation) from the straight-line distance.

In step 114, a routing is calculated, whereby the cost of routing is computed as: A for a link within a requested range; and A+B+X for a link outside the requested range where A and B are constants, and X is calculated based on the amount a link deviates from the requested range.

As represented in step 116, in the present example, a route is determined to be possible where the maximum deviation is within N percentage points of a requested range. Accordingly, the particular example shown in Figure 9 allows ranges to be displayed to a user having parameters which are slightly outside the range selected by the user. The value N can be selected to be a relatively small percentage, for example 1% or 2%, or a larger value such as 5% or 10%.

The route calculation algorithm employed by the processor 46 can be configured to increase a penalty gradient towards the high end of the gradient range.

Where the bottom of a gradient range is also set as a relatively steep grade, the system can be configured to penalize low-gradient routes. The use of the user's selectable inputs enables users purposely to choose steep gradients as opposed to shallow gradients, if this is what is desired.

Figure 10 is a schematic representation of a route selected from a start point 166 to an end point 168. As illustrated in Figure 8, the values at the nodes, or grid points 102, represent altitude values and the values on the links or vectors 104 between the nodes 102 represent gradients. * 14

Figure 10 illustrates that two possible routings are selected. In the example shown in Figure 10, it is assumed that the route has a gradient range between 0% and 10%. A first routing 120, shown by the solid black line in Figure 10, contains the fewest links outside the requested range. An alternative route 122, which deviates from the route 120 at two areas represented by the solid black dashed line contains more links which are outside the requested range, but reduces the distance by two segments. Accordingly, the presentation of the two alternative routes to the user can enable the user to make a better selection of the desired routing.

Figure 11 illustrates another example where the user selects that the route should be within a gradient range of 12% to 20%. As shown in Figure 11, a first routing 124 is illustrated by the solid black line and a second routing 126, which is shorter but includes sections which are steeper, is represented by the black dashed line.

It can be seen that an example of the present invention can allow the selection of a route within an allowed distance increase over a direct distance between two points, taking into account the gradient between the points and enables the selection of a route with a selectable deviation from the direct distance and a selectable routing outside a preferred gradient range. The preferred gradient and maximum detour presentations andlor values can optionally be varied by the user, to meet different requirements at the time (for example, hill racing or a leisurely drive).

User-accessible switches can be made available to the user so that the user can select a default setting or change a gradient range and a maximum detour range. The default settings can be configured to contain an algorithm automatically to reduce the default maximum gradient when the navigation system detects that a trailer connection is in use. For example, the navigation system, as indicated earlier, can be responsive to sensors provided in a vehicle, and one such example can be that iehicle messaging information can notify the navigation system of the additional optinnal fitment of a trailer, an attachment, or other loads.

There has been described a method and apparatus for navigating in which mapping data is provided that includes geographical mapping point data with altitude information. A user is able to select a journey from a geographical start point to a geographical end point and to select at least one desired gradient parameter for the S journey. At least one route is computed from the geographical start point to the geographical end point dependent upon the desired gradient parameters and the mapping data. The computed routing(s) can then be presented to the user. An example embodiment of the invention can calculate a route which forms a best match to a gradient range selected by a user.

The invention may be embodied in a computer program product for operating the processing apparatus 46 when the processing apparatus is a programmable device.

The computer program product may be in the form of a computer program on a carrier medium. The carrier medium could be a storage medium such as a solid state, magnetic, optical, magneto-optical or other storage medium. The carrier medium could be a transmission medium such as broadcast, telephonic, computer network, wired, wireless, electrical, electromagnetic optical or any other transmission medium.

Although the embodiments described above have been described in detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to include all such variations and modifications and their equivalents.

Claims (35)

1. A navigation apparatus comprising: mapping data storage for mapping data including geographical mapping point data, the geographical mapping point data including altitude information; input means for a user to select a journey from a geographical start point to a geographical end point and at least one desired gradient parameter for the journey; route processing means for computing at least one route from the start point to the end point dependent upon the desired gradient parameters and the mapping data; output means for presenting to the user the computed routing(s).

2. The navigation apparatus of claim 1, wherein the mapping data further includes gradient information in respect of vectors between the geographical mapping points, and the route processing means is responsive to the gradient information for computing the routing(s).

3. The navigation apparatus of claim 1 or claim 2, wherein the output means is operable to present a set of gradient parameters to the user for the user to select the at least one gradient parameter using the input means.

4. The navigation apparatus of any preceding claim, wherein the at least one gradient parameter comprises one or both of a minimum gradient and a maximum gradient.

5. The navigation apparatus of claim 4, wherein the output means is operable to present to the user either one or both of a set of minimum gradients and a set of maximum gradients and is operable, in response to a user selecting either a minimum gradient from a set of minimum gradients or a maximum gradient from a set of maximum gradients, to present to the user for selection available gradients from the other set of gradients in order to define a range of gradients between a minimum gradient and a maximum gradient.

* . 17

6. The navigation apparatus of any preceding claim, wherein the route processing means is configured to be responsive to selection of a geographical start point and a geographical end point for a journey to cause the output means to present a set of gradient parameters to the user for the user to select the at least one gradient parameter using the input means.

7. The navigation apparatus of any preceding claim, wherein the input means is further configured for a user to select a desired maximum deviation from a direct routing.

8. The navigation apparatus of claim 7, wherein the output means is operable to present a set of deviations from a direct routing to the user for the user to select the at least one gradient parameter using the input means.

9. The navigation apparatus of any preceding claim, wherein the route processing means is configured to be responsive to selection of a journey from a geographical start point to a geographical end point or to selection of at least one gradient parameter to cause the output means to present to the user a set of deviations from a direct routing for the user to select the at least one gradient parameter using the input means.

10. The navigation apparatus of any preceding claim, wherein the route processing means is operable to determine a plurality of potential routings, the output means is configured to present the plurality of routings to the user, and the input means is configured to permit the user to select one of the presented routings.

11. The navigation apparatus of any preceding claim, wherein the output means comprises at least one of a display device and a voiced instruction output apparatus.

12. The navigation apparatus of any preceding claim, wherein the input means comprises one of a touch sensitive display device, a manual selector or a voice capture and recognition apparatus.

13. The navigation apparatus of any preceding claim, comprising position determining means, the processing means being responsive to the position determining means.

14. The navigation apparatus of claim 13, wherein the processing means is responsive to position determining means to determine a geographical start point for a journey to be a current position of the navigation apparatus.

15. The navigation apparatus of claim 13 or claim 14, wherein the position determining means is operable to determine a position based on satellite signal information.

16. The navigation apparatus of any preceding claim, wherein the navigation apparatus is a vehicle navigation apparatus.

17. A vehicle comprising the navigation apparatus of any preceding claim.

18. A method for navigating using a navigation apparatus, the method comprising the navigation apparatus: providing mapping data including geographical mapping point data with altitude information; enabling a user to select a journey from a geographical start point to a geographical end point and to select at least one desired gradient parameter for the journey; computing at least one route from the geographical start point to the geographical end point dependent upon the desired gradient parameters and the mapping data; and presenting to the user the computed routing(s).

19. The method of claim 18, wherein the mapping data further includes gradient information in respect of vectors between the geographical mapping points, and the navigation apparatus is responsive to the gradient information for computing the routing(s).

20. The method of claim 18 or claim 19, comprising the navigation apparatus presenting a set of gradient parameters to the user for the user to select the at least one gradient parameter using the input means.

21. The method of any of claims 18 to 20, wherein the at least one gradient parameter comprises one or both of a minimum gradient and a maximum gradient.

22. The method of claim 21, comprising the navigation apparatus presenting to the user either one or both of a set of minimum gradients and a set of maximum gradients and, in response to a user selecting either a minimum gradient from a set of minimum gradients or a maximum gradient from a set of maximum gradients, presenting to the user for selection available gradients from the other set of gradients in order to define a range of gradients between a minimum gradient and a maximum gradient.

23. The method of any of claims 18 to 22, comprising the navigation apparatus responding to selection of a geographical start point and a geographical end point for a journey to present a set of gradient parameters to the user for the user to select the at least one gradient parameter using the input means.

24. The method of any of claims 18 to 23, comprising the navigation apparatus further enabling a user to select a desired maximum deviation from a direct routing.

25. The method of claim 24, comprising the navigation apparatus presenting a set of deviations from a direct routing to the user for the user to select the at least one gradient parameter using the input means.

26. The method of any of claims 18 to 25, comprising the navigation apparatus responding to selection ofa journey from a start point to an end point or to selection of * 20 at least one gradient parameter to present to the user a set of deviations from a direct routing for the user to select the at least one gradient parameter using the input means.

27. The method of any of any of claims 18 to 26, comprising the navigation apparatus determining a plurality of potential routings, presenting the plurality of routings to the user, and responding to user selection of one of the presented routings.

28. The method of any of claims 18 to 27, wherein the navigation apparatus presents information to a user using at least one of a display device and a voiced instruction output apparatus.

29. The method of any of claims 18 to 28, wherein the navigation apparatus receives input from the user using at least one of a touch sensitive display device, a manual selector or a voice capture and recognition apparatus.

30. The method of any of claims 18 to 29, comprising the navigation apparatus determining its current geographical position.

31. The method of claim 30, comprising the navigation apparatus taking its current geographical position as a geographical start point for a journey.

32. The method of claim 30 or claim 31, comprising the navigation apparatus determining its current position wherein the position determining means is operable to determine its current geographical position based on satellite signal information.

33. The method of any of claims 18 to 32 for navigating a vehicle.

34. A computer program product comprising program instructions for causing a programmable navigation apparatus to carry out the method of any of claims 18 to 33.

35. The computer program product of claim 34, comprising a machine readable medium, the machine readable medium carrying the program instructions.