WO2009143870A1

WO2009143870A1 - Navigation apparatus and method of generating a view therefor

Info

Publication number: WO2009143870A1
Application number: PCT/EP2008/004568
Authority: WO
Inventors: Olaf Achthoven
Original assignee: Tomtom International B.V.
Priority date: 2008-05-29
Filing date: 2008-05-29
Publication date: 2009-12-03
Also published as: TW200949208A

Abstract

A navigation apparatus (200) comprises a processing resource (202) that is operably coupled to a data store (214) comprising terrain data (294) relating to a three- dimensional terrain and feature data (296, 298) associated therewith. A location determination unit (202, 224) is also provided and capable of determining a location. A view generation engine (292) supported by the processing resource (202) provides output data receivable by a display device (206). The terrain data (294) is arranged as a network of triangular cells comprising a triangular cell (350) having respective height data associated with each vertex thereof; the triangular cell (350) is relevant to the location. The feature data (296, 298) comprises information concerning a feature (352) relevant to the location. The processing resource (202) accesses a part of the terrain data (294) and a part of the feature data (296, 298) relevant to the location, and the view generation engine represents in planar form the triangular cell (350) and the feature (352) relative thereto.

Description

NAVIGATION APPARATUS AND METHOD OF GENERATING A VIEW THEREFOR

Field of the Invention

The present invention relates to a navigation apparatus of the type that, for example, provides a three-dimensional view in respect of a location. The present invention also relates to a method of generating a view to be displayed by a navigation apparatus, the method being of the type that, for example, accesses terrain data to obtain information for generation of the view. The present invention further relates to a navigation apparatus of the type that, for example, provides a coloured three- dimensional view in respect of a location. The present invention also relates to a method of representing a terrain by a navigation apparatus, the method being of the type that, for example, accesses terrain data to obtain information for generation of the view.

Background to the Invention Portable computing devices, for example Portable Navigation Devices (PNDs) that include GPS (Global Positioning System) signal reception and processing functionality are well known and are widely employed as in-car or other vehicle navigation systems.

In general terms, a modern PND comprises a processor, memory (at least one of volatile and non-volatile, and commonly both), and map data stored within said memory. The processor and memory cooperate to provide an execution environment in which a software operating system may be established, and additionally it is commonplace for one or more additional software programs to be provided to enable the functionality of the PND to be controlled, and to provide various other functions. Typically these devices further comprise one or more input interfaces that allow a user to interact with and control the device, and one or more output interfaces by means of which information may be relayed to the user. Illustrative examples of output interfaces include a visual display and a speaker for audible output. Illustrative examples of input interfaces include one or more physical buttons to control on/off operation or other features of the device (which buttons need not necessarily be on the device itself but could be on a steering wheel if the device is built into a vehicle), and a microphone for detecting user speech. In one particular arrangement, the output interface display may be configured as a touch sensitive display (by means of a touch sensitive overlay or otherwise) additionally to provide an input interface by means of which a user can operate the device by touch.

Devices of this type will also often include one or more physical connector interfaces by means of which power and optionally data signals can be transmitted to and received from the device, and optionally one or more wireless transmitters/receivers to allow communication over cellular telecommunications and other signal and data networks, for example Bluetooth, Wi-Fi, Wi-Max, GSM, UMTS and the like. PNDs of this type also include a GPS antenna by means of which satellite- broadcast signals, including location data, can be received and subsequently processed to determine a current location of the device.

The PND may also include electronic gyroscopes and accelerometers which produce signals that can be processed to determine the current angular and linear acceleration, and in turn, and in conjunction with location information derived from the GPS signal, velocity and relative displacement of the device and thus the vehicle in which it is mounted. Typically, such features are most commonly provided in in-vehicle navigation systems, but may also be provided in PNDs if it is expedient to do so.

The utility of such PNDs is manifested primarily in their ability to determine a route between a first location (typically a start or current location) and a second location (typically a destination). These locations can be input by a user of the device, by any of a wide variety of different methods, for example by postcode, street name and house number, previously stored "well known" destinations (such as famous locations, municipal locations (such as sports grounds or swimming baths) or other points of interest), and favourite or recently visited destinations.

Typically, the PND is enabled by software for computing a "best" or "optimum" route between the start and destination address locations from the map data. A "best" or "optimum" route is determined on the basis of predetermined criteria and need not necessarily be the fastest or shortest route. The selection of the route along which to guide the driver can be very sophisticated, and the selected route may take into account existing, predicted and dynamically and/or wirelessly received traffic and road information, historical information about road speeds, and the driver's own preferences for the factors determining road choice (for example the driver may specify that the route should not include motorways or toll roads). In addition, the device may continually monitor road and traffic conditions, and offer to or choose to change the route over which the remainder of the journey is to be made due to changed conditions. Reai time traffic monitoring systems, based on various technologies (e.g. mobile phone data exchanges, fixed cameras, GPS fleet tracking) are being used to identify traffic delays and to feed the information into notification systems. PNDs of this type may typically be mounted on the dashboard or windscreen of a vehicle, but may also be formed as part of an on-board computer of the vehicle radio or indeed as part of the control system of the vehicle itself. The navigation device may also be part of a hand-held system, such as a PDA (Portable Digital Assistant), a media player, a mobile phone or the like, and in these cases, the normal functionality of the hand-held system is extended by means of the installation of software on the device to perform both route calculation and navigation along a calculated route.

Route planning and navigation functionality may also be provided by a desktop or mobile computing resource running appropriate software. For example, the Royal Automobile Club (RAC) provides an on-line route planning and navigation facility at http://www.rac.co.uk, which facility allows a user to enter a start point and a destination whereupon the server with which the user's computing resource is communicating calculates a route (aspects of which may be user specified), generates a map, and generates a set of exhaustive navigation instructions for guiding the user from the selected start point to the selected destination. The facility also provides for pseudo three-dimensional rendering of a calculated route, and route preview functionality which simulates a user travelling along the route and thereby provides the user with a preview of the calculated route.

In the context of a PND, once a route has been calculated, the user interacts with the navigation device to select the desired calculated route, optionally from a list of proposed routes. Optionally, the user may intervene in, or guide the route selection process, for example by specifying that certain routes, roads, locations or criteria are to be avoided or are mandatory for a particular journey. The route calculation aspect of the PND forms one primary function, and navigation along such a route is another primary function.

During navigation along a calculated route, it is usual for such PNDs to provide visual and/or audible instructions to guide the user along a chosen route to the end of that route, i.e. the desired destination. It is also usual for PNDs to display map information on-screen during the navigation, such information regularly being updated on-screen so that the map information displayed is representative of the current location of the device, and thus of the user or user's vehicle if the device is being used for in- vehicle navigation.

An icon displayed on-screen typically denotes the current device location, and is centred with the map information of current and surrounding roads in the vicinity of the current device location and other map features also being displayed. Additionally, navigation information may be displayed, optionally in a status bar above, below or to one side of the displayed map information, examples of navigation information include a distance to the next deviation from the current road required to be taken by the user, the nature of that deviation possibly being represented by a further icon suggestive of the particular type of deviation, for example a left or right turn. The navigation function also determines the content, duration and timing of audible instructions by means of which the user can be guided along the route. As can be appreciated a simple instruction such as "turn left in 100 m" requires significant processing and analysis. As previously mentioned, user interaction with the device may be by a touch screen, or additionally or alternately by steering column mounted remote control, by voice activation or by any other suitable method.

A further important function provided by the device is automatic route re- calculation in the event that: a user deviates from the previously calculated route during navigation (either by accident or intentionally); real-time traffic conditions dictate that an alternative route would be more expedient and the device is suitably enabled to recognize such conditions automatically, or if a user actively causes the device to perform route re-calculation for any reason. It is also known to allow a route to be calculated with user defined criteria; for example, the user may prefer a scenic route to be calculated by the device, or may wish to avoid any roads on which traffic congestion is likely, expected or currently prevailing. The device software would then calculate various routes and weigh more favourably those that include along their route the highest number of points of interest (known as POIs) tagged as being for example of scenic beauty, or, using stored information indicative of prevailing traffic conditions on particular roads, order the calculated routes in terms of a level of likely congestion or delay on account thereof. Other POI-based and traffic information-based route calculation and navigation criteria are also possible.

Although the route calculation and navigation functions are fundamental to the overall utility of PNDs, it is possible to use the device purely for information display, or "free-driving", in which only map information relevant to the current device location is displayed, and in which no route has been calculated and no navigation is currently being performed by the device. Such a mode of operation is often applicable when the user already knows the route along which it is desired to travel and does not require navigation assistance.

Devices of the type described above, for example the 920T model manufactured and supplied by TomTom International B. V., provide a reliable means for enabling users to navigate from one position to another. Such devices are of great utility when the user is not familiar with the route to the destination to which they are navigating. As mentioned above, the memory of the PND stores map data used by the PND not only to calculate routes and provide necessary navigation instructions to users, but also to provide visual information to users through the visual display of the PND.

As is known in the art, map information can be expressed in a number of ways and indeed can comprise a number of separate information components, which are used in combination by the PND. One aspect of map information is terrain information, which is needed by the PND in order to be aware of and represent surrounding terrain, or expressed another way, how the "land lies".

In this respect, it is known to record terrain information as grid data, each intersection of the grid having a longitude value, a latitude value and an associated height value. However, expression of the terrain data in grid form is disadvantageous, because matching certain cartographic features, for example roads, to the grid is difficult. For example, the difficulty arises as a result of stored road data typically comprising longitude and latitude data in respect of end points of a given road. Heights are respectively attributed to the end points, the heights adopted being the heights of the grid cells in which the end points respectively reside. However, a given grid cell can comprise a so-called "ridge" or maximum where the terrain inside the grid cell rises above values associated with grid cell corners or a so-called "valley" or minimum where the terrain inside the cell falls below the values associated with the grid cell corners. Consequently, if the end points reside in grid cells either side of the given grid cell, the heights of the end points can be such that the road extending through the grid cell can be represented as passing physically through the terrain or "floating" above the terrain, which is nonsensical. Indeed, even if the points of entry and exit of the given road with respect to the given grid cell are set to the heights at the entry and exit points of the given grid cell, the given road can still appear to pass through the terrain or above the terrain as opposed to residing on the terrain associated with the grid cell. In an attempt to alleviate this problem, when a height of a point on the given grid cell is required, unless the point coincides with an intersection of a point of known height of the given grid cell due to the existence of recorded height data, an interpolation of heights at neighbouring intersections can be performed by the PND in order to determine the height of the point under investigation and the relevant part of the road is then represented at the calculated height. Unfortunately, the use of interpolation does not always yield a correct result. For example, the given grid cell, D, having corners of heights (moving in a clockwise manner starting at the top left-hand corner) of: 10, 15, 10, 15, can have equal diagonally opposite values. Consequently, such a distribution of height data can be interpreted as the given grid cell, D, comprising a "valley" extending between two diagonally opposite heights of 10. Alternatively, the distribution of height data can be interpreted as the given grid cell, D, comprising a "ridge" extending between the two diagonally opposite heights of 15. As such, a representation of the given grid cell will not necessarily coincide with a representation of a point on the given road at an interpolated height value calculated and so a mismatch, which will be visually evident, can occur.

An additional difficulty associated with the terrain information relates to visualisation. Typically, known PNDs do not provide an indication of height of surrounding three-dimensional terrain. Consequently, it is difficult for a user, for example one driving through or near a mountain range, to distinguish between relative heights of neighbouring geographic features, for example mountains.

Summary of the Invention

According to a first aspect of the present invention, there is provided a Navigation apparatus comprising: a processing resource operably coupled to a data store, the data store comprising terrain data relating to a three-dimensional terrain and feature data associated therewith; a location determination unit operably coupled to the processing resource and capable of determining a location; a display device operably coupled to the processing resource, the processing resource supporting, when in use, a view generation engine and the display device being capable of receiving output data generated by the view generation engine; wherein the terrain data is arranged as a network of triangular cells comprising a triangular cell having respective height data associated with each vertex thereof, the triangular cell being relevant to the location; the feature data comprises information concerning a feature relevant to the location; and the processing resource is arranged to access, when in use, a part of the terrain data and a part of the feature data relevant to the location, and the view generation engine is arranged to represent in planar form the triangular cell and the feature relative thereto.

The triangular cell may be relevant to display of an environment associated with the location. The feature may be relevant to display of the environment associated with the location. The network of triangular cells may be a Triangulated Irregular Network.

The network of triangular cells may comprise another triangular cell located adjacent the triangular cell and having a height associated with a vertex thereof and sharing remaining vertices with the triangular cell. A common boundary may at least notionally extend between the shared remaining vertices. The common boundary may be substantially indicative of a convergent height.

The convergent height may be indicative of a peak formation represented by the triangular cell and the another triangular cell. The convergent height may be indicative of a trough formation represented by the triangular cell and the another triangular cell.

The processing resource may be arranged to represent at least part of the feature at a height relative to the triangular cell and the another triangular cell. The height of the at least part of the feature may be determined using the convergent height. The processing resource may be arranged to provide a first node and a second node in relation to the at least part of the feature; the first node and the second node may be indicative of limits of the at least part of the feature with respect to overlap with the triangular cell and/or the another triangular cell; and the first node and the second node may have respective node heights associated therewith substantially equal to the convergent height.

The height data respectively associated with the shared remaining vertices may be substantially the same. The feature data may comprise road data. The feature may be a road. The feature data may comprise land use data.

The view generation engine may be arranged to colour at least part of the planar representation of the triangular cell in accordance with a height-related colour scheme. The height-related colour scheme may comprise a palette of colours associated with a range of heights. The height-related colour scheme may comprise a plurality of height sub-ranges, each height sub-range of the plurality of height sub-ranges being associated with a colour. The height-related colour scheme may be user-defined.

The processing resource may be arranged to permit a first colour to be set in respect of a first height sub-range substantially at a first end of the range of heights and a second colour to be set in respect of a second height sub-range substantially at a second end of the range of heights, and to determine colours of the palette in respect of height sub-ranges between the first and second height sub-ranges.

The processing resource may be arranged to permit an intermediate colour to be set in respect of a height between the first and second ends of the range of heights and to determine colours of the palette between the first and intermediate colours and the intermediate and second colours.

According to a second aspect of the present invention, there is provided a navigation system comprising, a navigation apparatus as set forth above in relation to a first aspect of the invention; wherein the data store is remotely located from the navigation apparatus and accessible via a communications network. According to a third aspect of the present invention, there is provided a method of generating a view to be displayed by a navigation apparatus, the method comprising: determining a location associated with the navigation apparatus; accessing a part of terrain data and a part of feature data relevant to the location, the terrain data being arranged as a network of triangular cells comprising a triangular cell relevant to the location and having respective height data associated with each vertex thereof, and the feature data comprising information concerning a feature relevant to the location; and representing in planar form the triangular cell and the feature relative thereto.

According to a fourth aspect of the present invention, there is provided a navigation apparatus comprising: a processing resource operably coupled to a data store, the data store comprising terrain data relating to a three-dimensional terrain; a location determination unit operably coupled to the processing resource and capable of determining a location; a display device operably coupled to the processing resource, the processing resource supporting, when in use, a view generation engine and the display device being capable of receiving output data generated by the view generation engine; wherein the terrain data is arranged as a network of polygonal cells comprising a polygonal cell having respective height data associated with each vertex thereof, the polygonal cell being relevant to the location; and the processing resource is arranged to access, when in use, a part of the terrain data relevant to the location, and the view generation engine is arranged to represent in planar form the polygonal cell, the representation comprising colouring at least part of the planar representation of the polygonal cell in accordance with a height-related colour scheme.

The height-related colour scheme may comprise a palette of colours associated with a range of heights. The height-related colour scheme may comprise a plurality of height sub-ranges, each height sub-range of the plurality of height sub-ranges being associated with a colour. The height-related colour scheme may be user-defined.

The processing resource may be arranged to permit, a first colour to be set in respect of a first height sub-range substantially at a first end of the range of heights and a second colour to be set in respect of a second height sub-range substantially at a second end of the range of heights, and to determine colours of the palette in respect of height sub-ranges between the first and second height sub-ranges.

The processing resource may be arranged to permit an intermediate colour to be set in respect of a height between the first and second ends of the range of heights and to determine colours of the palette between the first and intermediate colours and the intermediate and second colours. According to a fifth aspect of the present invention, there is provided a method of representing a terrain by a navigation apparatus, the method comprising: determining a location of the navigation apparatus; accessing a part of terrain data relevant to the location, the terrain data being arranged as a network of polygonal cells comprising a polygonal cell having respective height data associated with each vertex thereof, the polygonal cell being relevant to the location; representing the polygonal cell in planar form; and colouring at least part of the planar representation of the polygonal cell in accordance with a height-related colour scheme.

According to a sixth aspect of the present invention, there is provided a computer program element comprising computer program code means to make a computer execute the method as set forth above in relation to the third or fifth aspects of the invention.

The computer program element may be embodied on a computer readable medium.

According to a seventh aspect of the present invention, there is provided a data store of a navigation apparatus comprising terrain data, the terrain data being arranged as a network of triangular cells comprising a triangular cell having respective height data associated with each vertex thereof.

Advantages of these embodiments are set out hereafter, and further details and features of each of these embodiments are defined in the accompanying dependent claims and elsewhere in the following detailed description. It is thus possible to provide an apparatus and method capable of representing feature data with improved accuracy and not in a nonsensical manner. Consequently, user experience is enhanced, because the user is not placed in a position where it is possible to conclude, incorrectly, that the apparatus is malfunctioning. As a result, rate of return of correctly functioning products to a manufacturer is reduced as are enquires due to incorrect suspicions of malfunction. Additionally, terrain is represented in a more accurate manner than when grid cell data is used. It is also possible to provide an apparatus and method that has improved visual display accuracy and clarity by virtue of a user being able to visualise relative heights of geographic features. Furthermore, the visual appearance presented to the user is enhanced and more pleasing to the eye. Height information is also communicated in a clear manner, thereby reducing instances of driver confusion, insecurity, hesitation and hence driver workload resulting in a safer driving experience.

Brief Description of the Drawings At least one embodiment of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 is a schematic illustration of an exemplary part of a Global Positioning System (GPS) usable by a navigation device;

Figure 2 is a schematic diagram of a communications system for communication between a navigation device and a server; Figure 3 is a schematic illustration of electronic components of the navigation device of Figure 2 or any other suitable navigation device;

Figure 4 is a schematic diagram of an arrangement of mounting and/or docking a navigation device;

Figure 5 is a schematic representation of an architectural stack employed by the navigation device of Figure 3;

Figure 6 is a schematic illustration of entities supported by a processor of the navigation device of Figure 3;

Figure 7 is a flow diagram of a method of generating a view for the navigation device of Figure 3 and constituting a first embodiment of the invention; Figures 8 to 16 are screen shots from the navigation device in accordance with a part of the method of Figure 7;

Figure 17 is a schematic diagram of projection of three-dimensional data onto a two-dimensional plane;

Figure 18 is a screen shot of a view displayed by the navigation device of Figure 3 relating to the first embodiment of the invention following the method of Figure 7 and a second embodiment of the invention;

Figure 19 is another screen shot of another view displayed by the navigation device in relation to the first embodiment and the second embodiment of the invention; and Figure 20 is a flow diagram of a method of colouring a view constituting the second embodiment of the invention;

Figure 21 is a schematic diagram of a colour palette used in relation to the method of Figure 20; and

Figure 22 is a screen shot of an approach to a destination displayed by the navigation device.

Detailed Description of Preferred Embodiments

Throughout the following description identical reference numerals will be used to identify like parts. Embodiments of the present invention will now be described with particular reference to a PND. It should be remembered, however, that the teachings of the present invention are not limited to PNDs but are instead universally applicable to any type of processing device that is configured to execute navigation software in a portable manner so as to provide route planning and navigation functionality. It follows therefore that in the context of the present application, a navigation device is intended to include (without limitation) any type of route planning and navigation device, irrespective of whether that device is embodied as a PND, a vehicle such as an automobile, or indeed a portable computing resource, for example a portable personal computer (PC), a mobile telephone or a Personal Digital Assistant (PDA) executing route planning and navigation software. It will also be apparent from the following that the teachings of the present invention even have utility in circumstances, where a user is not seeking instructions on how to navigate from one point to another, but merely wishes to be provided with a view of a given location. In such circumstances the "destination" location selected by the user need not have a corresponding start location from which the user wishes to start navigating, and as a consequence references herein to the "destination" location or indeed to a "destination" view should not be interpreted to mean that the generation of a route is essential, that travelling to the "destination" must occur, or indeed that the presence of a destination requires the designation of a corresponding start location.

With the above provisos in mind, the Global Positioning System (GPS) of Figure 1 and the like are used for a variety of purposes. In general, the GPS is a satellite-radio based navigation system capable of determining continuous position, velocity, time, and in some instances direction information for an unlimited number of users. Formerly known as NAVSTAR, the GPS incorporates a plurality of satellites which orbit the earth in extremely precise orbits. Based on these precise orbits, GPS satellites can relay their location to any number of receiving units.

The GPS system is implemented when a device, specially equipped to receive GPS data, begins scanning radio frequencies for GPS satellite signals. Upon receiving a radio signal from a GPS satellite, the device determines the precise location of that satellite via one of a plurality of different conventional methods. The device will continue scanning, in most instances, for signals until it has acquired at least three different satellite signals (noting that position is not normally, but can be determined, with only two signals using other triangulation techniques). Implementing geometric triangulation, the receiver utilizes the three known positions to determine its own two-dimensional position relative to the satellites. This can be done in a known manner. Additionally, acquiring a fourth satellite signal allows the receiving device to calculate its three dimensional position by the same geometrical calculation in a known manner. The position and velocity data can be updated in real time on a continuous basis by an unlimited number of users.

As shown in Figure 1 , the GPS system 100 comprises a plurality of satellites 102 orbiting about the earth 104. A GPS receiver 106 receives spread spectrum GPS satellite data signals 108 from a number of the plurality of satellites 102. The spread spectrum data signals 108 are continuously transmitted from each satellite 102, the spread spectrum data signals 108 transmitted each comprise a data stream including information identifying a particular satellite 102 from which the data stream originates.

The GPS receiver 106 generally requires spread spectrum data signals 108 from at least three satellites 102 in order to be able to calculate a two-dimensional position. Receipt of a fourth spread spectrum data signal enables the GPS receiver 106 to calculate, using a known technique, a three-dimensional position.

Turning to Figure 2, a navigation device 200 comprising or coupled to the GPS receiver device 106, is capable of establishing a data session, if required, with network hardware of a "mobile" or telecommunications network via a mobile device (not shown), for example a mobile telephone, PDA, and/or any device with mobile telephone technology, in order to establish a digital connection, for example a digital connection via known Bluetooth technology. Thereafter, through its network service provider, the mobile device can establish a network connection (through the Internet for example) with a server 150. As such, a "mobile" network connection can be established between the navigation device 200 (which can be, and often times is, mobile as it travels alone and/or in a vehicle) and the server 150 to provide a "real-time" or at least very "up to date" gateway for information.

The establishing of the network connection between the mobile device (via a service provider) and another device such as the server 150, using the Internet for example, can be done in a known manner. In this respect, any number of appropriate data communications protocols can be employed, for example the TCP/IP layered protocol. Furthermore, the mobile device can utilize any number of communication standards such as CDMA2000, GSM₁ IEEE 802.11 a/b/c/g/n, etc. Hence, it can be seen that the internet connection may be utilised, which can be achieved via data connection, via a mobile phone or mobile phone technology within the navigation device 200 for example.

Although not shown, the navigation device 200 may, of course, include its own mobile telephone technology within the navigation device 200 itself (including an antenna for example, or optionally using the internal antenna of the navigation device

200). The mobile phone technology within the navigation device 200 can include internal components, and/or can include an insertable card (e.g. Subscriber Identity Module (SIM) card), complete with necessary mobile phone technology and/or an antenna for example. As such, mobile phone technology within the navigation device 200 can similarly establish a network connection between the navigation device 200 and the server 150, via the Internet for example, in a manner similar to that of any mobile device.

For telephone settings, a Bluetooth enabled navigation device may be used to work correctly with the ever changing spectrum of mobile phone models, manufacturers, etc., model/manufacturer specific settings may be stored on the navigation device 200 for example. The data stored for this information can be updated.

In Figure 2, the navigation device 200 is depicted as being in communication with the server 150 via a generic communications channel 152 that can be implemented by any of a number of different arrangements. The communication channel 152 generically represents the propagating medium or path that connects the navigation device 200 and the server 150. The server 150 and the navigation device 200 can communicate when a connection via the communications channel 152 is established between the server 150 and the navigation device 200 (noting that such a connection can be a data connection via mobile device, a direct connection via personal computer via the internet, etc.).

The communication channel 152 is not limited to a particular communication technology. Additionally, the communication channel 152 is not limited to a single communication technology; that is, the channel 152 may include several communication links that use a variety of technology. For example, the communication channel 152 can be adapted to provide a path for electrical, optical, and/or electromagnetic communications, etc. As such, the communication channel 152 includes, but is not limited to, one or a combination of the following: electric circuits, electrical conductors such as wires and coaxial cables, fibre optic cables, converters, radio-frequency (RF) waves, the atmosphere, free space, etc. Furthermore, the communication channel 152 can include intermediate devices such as routers, repeaters, buffers, transmitters, and receivers, for example. In one illustrative arrangement, the communication channel 152 includes telephone and computer networks. Furthermore, the communication channel 152 may be capable of accommodating wireless communication, for example, infrared communications, radio frequency communications, such as microwave frequency communications, etc. Additionally, the communication channel 152 can accommodate satellite communication.

The communication signals transmitted through the communication channel 152 include, but are not limited to, signals as may be required or desired for given communication technology. For example, the signals may be adapted to be used in cellular communication technology such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), Global System for Mobile Communications (GSM)₁ etc. Both digital and analogue signals can be transmitted through the communication channel 152. These signals may be modulated, encrypted and/or compressed signals as may be desirable for the communication technology.

The server 150 includes, in addition to other components which may not be illustrated, a processor 154 operatively connected to a memory 156 and further operatively connected, via a wired or wireless connection 158, to a mass data storage device 160. The mass storage device 160 contains a store of navigation data and map information, and can again be a separate device from the server 150 or can be incorporated into the server 150. The processor 154 is further operatively connected to transmitter 162 and receiver 164, to transmit and receive information to and from navigation device 200 via communications channel 152. The signals sent and received may include data, communication, and/or other propagated signals. The transmitter 162 and receiver 164 may be selected or designed according to the communications requirement and communication technology used in the communication design for the navigation system 200. Further, it should be noted that the functions of transmitter 162 and receiver 164 may be combined into a single transceiver.

As mentioned above, the navigation device 200 can be arranged to communicate with the server 150 through communications channel 152, using transmitter 166 and receiver 168 to send and receive signals and/or data through the communications channel 152, noting that these devices can further be used to communicate with devices other than server 150. Further, the transmitter 166 and receiver 168 are selected or designed according to communication requirements and communication technology used in the communication design for the navigation device 200 and the functions of the transmitter 166 and receiver 168 may be combined into a single transceiver as described above in relation to Figure 2. Of course, the navigation device 200 comprises other hardware and/or functional parts, which will be described later herein in further detail.

Software stored in server memory 156 provides instructions for the processor 154 and allows the server 150 to provide services to the navigation device 200. One service provided by the server 150 involves processing requests from the navigation device 200 and transmitting navigation data from the mass data storage 160 to the navigation device 200. Another service that can be provided by the server 150 includes processing the navigation data using various algorithms for a desired application and sending the results of these calculations to the navigation device 200.

The server 150 constitutes a remote source of data accessible by the navigation device 200 via a wireless channel. The server 150 may include a network server located on a local area network (LAN), wide area network (WAN), virtual private network (VPN), etc.

The server 150 may include a personal computer such as a desktop or laptop computer, and the communication channel 152 may be a cable connected between the personal computer and the navigation device 200. Alternatively, a personal computer may be connected between the navigation device 200 and the server 150 to establish an internet connection between the server 150 and the navigation device 200.

The navigation device 200 may be provided with information from the server 150 via information downloads which may be periodically updated automatically or upon a user connecting the navigation device 200 to the server 150 and/or may be more dynamic upon a more constant or frequent connection being made between the server 150 and navigation device 200 via a wireless mobile connection device and TCP/IP connection for example. For many dynamic calculations, the processor 154 in the server 150 may be used to handle the bulk of processing needs, however, a processor (not shown in Figure 2) of the navigation device 200 can also handle much processing and calculation, oftentimes independent of a connection to a server 150.

Referring to Figure 3, it should be noted that the block diagram of the navigation device 200 is not inclusive of all components of the navigation device, but is only representative of many example components. The navigation device 200 is located within a housing (not shown). The navigation device 200 includes a processing resource comprising, for example, the processor 202 mentioned above, the processor 202 being coupled to an input device 204 and a display device, for example a display screen 206. Although reference is made here to the input device 204 in the singular, the skilled person should appreciate that the input device 204 represents any number of input devices, including a keyboard device, voice input device, touch panel and/or any other known input device utilised to input information. Likewise, the display screen 206 can include any type of display screen such as a Liquid Crystal Display (LCD), for example.

In one arrangement, one aspect of the input device 204, the touch panel, and the display screen 206 are integrated so as to provide an integrated input and display device, including a touchpad or touchscreen input 250 (Figure 4) to enable both input of information (via direct input, menu selection, etc.) and display of information through the touch panel screen so that a user need only touch a portion of the display screen 206 to select one of a plurality of display choices or to activate one of a plurality of virtual or "soft" buttons. In this respect, the processor 202 supports a Graphical User Interface (GUI) that operates in conjunction with the touchscreen. In the navigation device 200, the processor 202 is operatively connected to and capable of receiving input information from input device 204 via a connection 210, and operatively connected to at least one of the display screen 206 and the output device 208, via respective output connections 212, to output information thereto. The navigation device 200 may include an output device 208, for example an audible output device (e.g. a loudspeaker). As the output device 208 can produce audible information for a user of the navigation device 200, it is should equally be understood that input device 204 can include a microphone and software for receiving input voice commands as well. Further, the navigation device 200 can also include any additional input device 204 and/or any additional output device, such as audio input/output devices for example. The processor 202 is operatively connected to memory 214 via connection 216 and is further adapted to receive/send information from/to input/output (I/O) ports 218 via connection 220, wherein the I/O port 218 is connectible to an I/O device 222 external to the navigation device 200. The external I/O device 222 may include, but is not limited to an external listening device, such as an earpiece for example. The connection to I/O device 222 can further be a wired or wireless connection to any other external device such as a car stereo unit for hands-free operation and/or for voice activated operation for example, for connection to an earpiece or headphones, and/or for connection to a mobile telephone for example, wherein the mobile telephone connection can be used to establish a data connection between the navigation device 200 and the Internet or any other network for example, and/or to establish a connection to a server via the Internet or some other network for example.

Figure 3 further illustrates an operative connection between the processor 202 and an antenna/receiver 224 via connection 226, wherein the antenna/receiver 224 can be a GPS antenna/receiver for example. It should be understood that the antenna and receiver designated by reference numeral 224 are combined schematically for illustration, but that the antenna and receiver may be separately located components, and that the antenna may be a GPS patch antenna or heiicai antenna for example.

It will, of course, be understood by one of ordinary skill in the art that the electronic components shown in Figure 3 are powered by one or more power sources (not shown) in a conventional manner. As will be understood by one of ordinary skill in the art, different configurations of the components shown in Figure 3 are contemplated. For example, the components shown in Figure 3 may be in communication with one another via wired and/or wireless connections and the like. Thus, the navigation device 200 described herein can be a portable or handheld navigation device 200.

In addition, the portable or handheld navigation device 200 of Figure 3 can be connected or "docked" in a known manner to a vehicle such as a bicycle, a motorbike, a car or a boat for example. Such a navigation device 200 is then removable from the docked location for portable or handheld navigation use.

Referring to Figure 4, the navigation device 200 may be a unit that includes the integrated input and display device 206 and the other components of Figure 2 (including, but not limited to, the internal GPS receiver 224, the microprocessor 202, a power supply (not shown), memory systems 214, etc.).

The navigation device 200 may sit on an arm 252, which itself may be secured to a vehicle dashboard/window/etc, using a suction cup 254. This arm 252 is one example of a docking station to which the navigation device 200 can be docked. The navigation device 200 can be docked or otherwise connected to the arm 252 of the docking station by snap connecting the navigation device 200 to the arm 252 for example. The navigation device 200 may then be rotatable on the arm 252. To release the connection between the navigation device 200 and the docking station, a button (not shown) on the navigation device 200 may be pressed, for example. Other equally suitable arrangements for coupling and decoupling the navigation device 200 to a docking station are well known to persons of ordinary skill in the art.

Turning to Figure 5, the processor 202 and memory 214 cooperate to support a BIOS (Basic Input/Output System) 282 that functions as an interface between functional hardware components 280 of the navigation device 200 and the software executed by the device. The processor 202 then loads an operating system 284 from the memory 214, which provides an environment in which application software 286 (implementing some or all of the above described route planning and navigation functionality) can run. The application software 286 provides an operational environment including the GUI that supports core functions of the navigation device, for example map viewing, route planning, navigation functions and any other functions associated therewith. In this respect, part of the application software 286 comprises a view generation module 288. Turning to Figure 6, the view generation module 288 supported by the processor 202 comprises a map data processor 290 capable of communicating with a view generation engine 292. The map data processor is capable of accessing the memory 214 in order to access map data 293, the map data comprising terrain data 294, land use data 296 and road data 298. The functionality of the view generation module 288 will now be described in the context of a journey. The terrain data 294 comprises data that, using cartographic terminology, defines "relief or elevations and depressions of land or sea bed. The land use data and road data constitute feature data. Using cartographic terminology again, the feature data relates to "culture" or features constructed by human-kind that are under, on, or above the ground which are delineated on a map. These include roads, trails, buildings, canals, sewer systems, and boundary lines. Examples of land use data is: Built Up Area, Sea, Big Lakes Rivers, Rivers, Canals, Small Canals, Ponds, City Park, Regional Park, Woodland, Island, Beach Dune Sand, Industrial Zone, Industrial Harbor, Moor Heath, Marsh, Pedestrian Zone, Airport, Runway Aircraft Roads, Postal District, Building, Suburbs, Company Ground, Freeport, Amusement Park Ground, Camping Site Ground, Castle Ground, Church Ground, Golf Course Ground, Government Building Ground, Holiday Area Ground, Hospital Ground, Hotel Motel Ground, Library Ground, Museum Ground, Nature Reserve Ground, Parking Area Ground, Petrol Station Ground, Place Of Interest Building, Monument Ground, Railway Station Ground, Recreational Area Ground, Restaurant Ground, Rest Area Ground, Rocks Ground, Sports Hall Ground, Stadium Ground, University College Ground, Walking Terrain Ground, Zoo Ground, Institution, Other Land use, Cemetery Ground, Military Territory, Shopping Center Ground, Agriculture, Vineyards, Fruit Trees, Olive Groves, Pastures, Broadleaved Forest, Coniferous Forest, Mixed Forest, Scrub, Rocks, Glaciers Snow, lntertidal Flats, Townblock City Block, Townblock Sand Area, Townblock Marsh, Townblock Forest, Townblock Grass, Townblock Planted Area, Townblock Water System, Townblock Bank Area, Townblock Swimming Pool, Townblock High Way, Townblock National Route, Townblock Principal Road, Townblock Other Road, Townblock WalkWay, Townblock Garden Path, Townblock Tunnel, Townblock Medium Strip, Townblock Hospital, Townblock School, Townblock Factory, TownblockDam, Townblock Railway Ground, Townblock Paved Area, Townblock Incomplete Area, Rail Road Station, Hospital, School, Factory, Place Of Worship, and/or Cultural Facility.

Referring now to Figures 7 to 16, an illustrative destination location input process (Step 400) will firstly be described in respect of a user whose start location is an airport in Lyon, France, and who wishes to navigate to a street address in Grenoble, France, for which the user knows the street name and building number. Although not shown, the user uses a settings menu option supported by the application software 286 in order to select view generation in a three-dimensional mode. When this user switches on the navigation device 200, the device 200 acquires a

GPS fix and calculates (in a known manner) the current location of the navigation device 200. The user is then presented, as shown in Figure 8, with a display 300 showing in pseudo three-dimensions the local environment 302 in which the navigation device 200 is determined to be located, and in a region 304 of the display 300 below the local environment a series of control and status messages. By touching the display of the local environment 302, the navigation device 200 switches to display (as shown in Figure 9) a series of virtual or soft buttons 306 by means of which a user can, inter alia, input a destination to which they wish to navigate.

By touching the "Navigate to" virtual button 308, the navigation device 200 switches to display (as shown in Figure 10) a plurality of virtual buttons that are each associated with a different category of selectable destinations. In this instance, the display shows a "home" button that if pressed would set the destination to a stored home location. The "favourite" button, if pressed, reveals a list of destinations that the user has previously stored in the navigation device 200 and if one of these destinations is then selected the destination for the route to be calculated is set to the selected previously stored destination. The "recent destination" soft button, if pressed, reveals a list of selectable destinations held in the memory of the navigation device 200 and to which the user has recently navigated. Selection of one of the destinations populating this list would set the destination location for this route to the selected (previously visited) location. The "point of interest" button, if pressed, reveals a number of options by means of which a user can opt to navigate to any of a plurality of locations, such as Automatic Teller Machines (ATMs), petrol stations or tourist attractions for example, that have been pre-stored in the navigation device 200 as locations to which a user of the navigation device 200 might want to navigate to. The triangular "arrow" shaped virtual button provides access to additional sub-menu options relating to the "Navigate to ..." menu option, and an "address" button 310 commences a process by which the user can input the street address of the destination to which the user wishes to navigate.

Since the user, in this example, knows the street address of the destination to which the user wishes the navigation device 200 to navigate, it is assumed that the "address" button 310 is operated (by touching the button displayed on the touchscreen), whereupon (as shown in Figure 11) the user is presented with a series of address input options - in particular for address input by "city centre", by "postcode", by "crossing or intersection" (for example a junction of two roads) and by "street and house number".

In this example, the user knows the street address and house number of the destination and hence selects the "street and house number" virtual button 312 whereupon the user is then presented, as shown in Figure 12, a prompt 314 to enter the name of the city to which they wish to navigate, a flag button 316 by means of which the user can select the country in which the desired city is located, and a virtual keyboard 318 that may be operated by the user, if necessary, to input the name of the destination city. In this instance the user has previously navigated to locations in Lyon and Grenoble, and the navigation device 200 therefore additionally provides the user with a list 320 of selectable cites.

The user in this instance wishes to navigate to Grenoble, and on selection of Grenoble from the list 320 the navigation device 200 displays, as shown in Figure 13, the virtual keyboard 318 by means of which a user can input street names, a prompt 322 for entry of a streetname and, in this instance, as the user has previously navigated to a street in Grenoble, a list 324 of selectable streets in Grenoble.

In this example, the user wishes to return to the street, Avenue Du General De Gaulle previously visited by the user, the user selects Avenue Du General De Gaulle from the displayed list 324.

Once a street has been selected, the navigation device 200 then displays a restricted, largely numeric, virtual keypad 326 and prompts the user, by means of prompt 328, to enter the number of the house in the selected street and city to which the user wishes to navigate. If the user has previously navigated to a building number in this street, then that number (as shown in Figure 14) is initially shown. If, as in this instance, the user wishes to navigate to No. 6, Avenue Du General De Gaulle once again, then the user need only touch a "done" virtual button 330 displayed at the bottom right hand corner of the display 300. If the user should wish to navigate to a different building number in Avenue Du General De Gaulle, then all the user need do is operate the virtual keypad 328 to input an appropriate building number.

Once the building number has been input or selected, the user is asked in Figure 15, whether a particular arrival time is required. If the user should push the "yes" button, then functionality is invoked that estimates the time required to travel to the destination and advises the user when they should leave (or if they are running late, should have left) their current location in order to arrive at their destination on time. In this instance, the user is not concerned about arriving at a particular time and hence selects the "no" virtual button.

Selecting the "no" button 332 causes the navigation device 200 to calculate a route between the current location and the selected destination and to display that route 334, as shown in Figure 16, on a relatively low magnification map that shows the entire route. The user is also provided with a "done" virtual button 336 which the user can press to indicate the calculated route is acceptable, a "find alternative" button 338 that the user can press to cause the navigation device 200 to calculate another route to the selected destination, and a "details" button 340 that a user can press to reveal selectable options for the display of more detailed information concerning the currently displayed route 334.

In this instance, it is assumed that the user considers the displayed route acceptable, and once the "done" button 336 has been pressed the user is presented, with three-dimensional view (not shown) of the current, start, location for the navigation device 200.

The user then commences their journey and the navigation device 200 guides the user, in a known manner, by updating the map in accordance with determined changes in location of the navigation device 200, and by providing the user with visual and, optionally, audible navigation instructions.

Once the destination has been set by the user and the navigation device 200 has commenced navigating the user, the navigation device 200, via the processor 202 and the GPS receiver 224 constituting a location determination unit, monitors (Step 402) the location of the navigation device 200. Once the navigation device 200 has progressed a sufficient distance along the route planned by the application software 286 of the navigation device 200, it is necessary to update a three-dimensional view displayed by the display device 206. Using longitude and latitude data relating to the location of the navigation device 200, the map data processor 290 accesses the map data 293 and retrieves terrain data 294, land use data 296 and road data 298.

In order to best describe generation of a view, generation of the view will now be described in the context of the navigation device 200 having advanced a considerable distance from the start location, the navigation device 200 passing through a relatively rural environment whilst following the route calculated. In this respect, the rural environment comprises mountainous regions that need to be displayed by the navigation device 200. As mentioned above, the map data processor 290 accesses (Step 404) the map data 293 appropriate to the location en-route of the navigation device 200. The quantity of data that it is necessary to retrieve from the memory 214 in order to provide a complete view at the location is a matter of design choice not directly relevant to this example and so, for the sake of conciseness and clarity of description, will not be described further herein.

The terrain data 294 used in this example is obtained from Tele Atlas NV, The Netherlands and has been pre-processed in order to convert the data obtained from a grid cell form to a triangular network form, for example a Triangulated Irregular Network (TIN) form. Of course, the skilled person should appreciate that the terrain data 294 can be provided already in the triangular network form, obviating the need to pre-process grid cell data.

The TIN terrain data 294 provided comprises a plurality of triangular cells, each vertex of a given triangular cell having respective height data associated therewith. The data relating to triangular cells relevant to the location determined are virtually arranged by the map data processor 290 in memory in order to obtain a three-dimensional

(undisplayed) representation of the terrain at the location.

Referring to Figure 17, a first triangular cell 350 and a second triangular cell 362 are, as described above, virtually arranged (Step 408) in three-dimensional space by determining (Step 406) the respective heights of the vertices of the triangular cell 350. In this example, the first and second triangular cells 350, 362 share vertices resulting in a notional common boundary 364 therebetween. The shared vertices of the first and second triangular cells 350, 362 share a first substantially common height, hi, the remaining (unshared) vertices of the first and second triangular cells 350, 362 also share a second substantially common height, h₂, that is less than, in this example, the first height, Ki₁. Consequently, the heights of surfaces defined by the first and second triangular cells 350, 362 converge to a convergent height at or around the notional boundary 364.

Relevant road data retrieved from the road data 298 stored in memory 214 is also analysed and a road 352, based upon the longitude and latitude values of end points of the road, is also virtually arranged (Step 408) in the three-dimensional space relative to the first and second triangular cells 350, 362. An entry point or node 354 and an exit point or node 356 of the road 352 with respect to the first triangular cell 350 are set at respective heights obtained from the height data relating to the triangular cell 350, for example by interpolation. Similarly, the exit point 356 constitutes another entry point in respect of the second triangular cell 362, another exit point 357 being set in respect of the second triangular cell 362. It should, however, be appreciated that the road data relating to the road 352 is, in this example, delimited by start and end longitude and latitude values for a given length of the road that can extend beyond the first and second triangular cells 350, 362. However, entry and exit points are set in respect of each triangular cell. In this example, no land use data 296 is relevant to the location determined and so is not required. However, the methodology for virtually arranging the land use data in the three-dimensionai space is analogous to that described above in relation to the road data.

Once the terrain data and road data relevant to the location determined have been virtually arranged, the virtually arranged three-dimensional data is projected (Step 410) by the view generation engine 292 onto a two-dimensional plane 358 using any suitable technique, for example a so-called "rasterisation" technique. In this respect, a three-dimensional view 360 on a two-dimensional plane 358 of the triangular cell 350 and a portion of the road 352 passing therethrough is created. Of course, the skilled person should appreciate that many other triangular cells are projected onto the two- dimensional plane along with associated relevant land use and/or road data in order to complete the view required.

Following projection onto the two-dimensional plane 358, the view generation engine 292 passes the view data generated to the display driver for display (Step 412) of a frame of navigation progress animation. Examples of the resulting view generated of the road 370 in the mountainous region mentioned above are depicted in Figures 18 and 19. The map data generator 290 then determines (Step 414) whether it is necessary to display a subsequent frame by reference to the determined location and progress along the route calculated by the application software 286.

In another embodiment, the TIN terrain data can be stored by and obtained from the data store 160 coupled to the server 150, the terrain data being retrieved via a communications network.

Turning to Figure 20, in the above examples, the triangular cells presented by the navigation device 200 are coloured or filled in accordance with the following colouring technique. After retrieval (Step 404) of the terrain data, for example relating to the triangular cell 350, the map data processor 290 analyses (Step 416) the heights respectively associated with each vertex of the triangular cell 350 and calculates (Step 418) an average height. The average height calculated is then passed to the view generation engine 292 with other data mentioned above necessary to achieve generation of the three-dimensional view 360 in the two dimensional plane 358. When generating the three-dimensional view in the two-dimensional plane, the view generation engine 292 accesses (Step 420) a colour palette (Figure 21) and identifies a respective colour corresponding to the average height calculated for each triangular cell to feature in the view to be displayed and assigns (Step 422) a colour to each triangular cell when generating the projection of the triangular cells, the projection being respectively filled in the colours selected. In this respect, the colours are assigned from a palette of 265 colours, the palette constituting a height-related coiour scheme.

Referring to Figure 21 , the palette 450 comprises a plurality of colours that relate to a range of heights. Each colour is assigned to a sub-range of colours within the range of heights. In this example, the palette is pre-configured. However, the skilled person should appreciate that the palette can be user-selected, the application software 286, through the GUI, allowing the user to select a first colour 452 at one end of the range of heights and a second colour 454 at another end of the range of heights. The application software 286 then linearly distributes colours by modifying one or more parameters of a colour scheme employed, for example a Red Green Blue (RGB) scheme or a Hue Saturation Value (HSV) scheme, in order to allocate colours to sub-ranges within the range of heights. Optionally, the user can be allowed to select an intermediate colour 456 between the first and second colours 452, 454, for example, substantially in the middle of the range of heights, and the application software 286 then calculates the intervening colours between the first colour 452 and the intermediate colour 456 and the intermediate colour 456, and the second colour 454.

Returning to the generation of the view to be displayed, once the fill colour has been selected from the palette, for example by a look-up process, and the other three- dimensional view data in respect of the two-dimensional plane 358 has been generated, the view generation engine 292 passes the view data generated to the display driver for display (Step 412) of a frame of navigation progress animation. Examples of the resulting view generated in the mountainous region mentioned above are depicted in Figures 18 and 19. As previously described, the map data generator 290 then determines (Step 414) whether it is necessary to display a subsequent frame by reference to the determined location and progress along the route calculated by the application software 286 in the manner described previously.

The resulting three-dimensional view, when displayed, provides a visual indication of variation in height and also a visual indication of height between geographical features, for example mountains, as can be seen in Figures 18 and 19. In this example, the palette transitions from a green colour at lowest heights 372 to a yellow or white colour at highest heights 374, the choice of white being particularly appropriate to represent heights at which snow is likely to be present.

It should be appreciated that the above colouring technique need not only be used with terrain data that comprises TIN data, but other forms of representing terrain data can be used, for example grid cell data or other suitable polygonal data. Referring to Figure 22, assuming the user follows the instructions provided by the navigation device 200, the navigation device 200 eventually displays a schematic representation of the destination (in this instance: 6 Avenue Du General De Gaulle) and a chequered flag 376.

In another embodiment, the colouring of each triangular cell can be more detailed by interpolating colours than through use of a single colour per cell. Alternatively, instead of calculating an average height, height values associated with, for example the triangular cell 350, are calculated corresponding to pixels of the three-dimensional view 360 of the triangular cell projected onto the two-dimensional plane, the heights being calculated by interpolation and the palette accessed in order to set respective colours for each pixel. It will also be appreciated that whilst various aspects and embodiments of the present invention have heretofore been described, the scope of the present invention is not limited to the particular arrangements set out herein and instead extends to encompass all arrangements, and modifications and alterations thereto, which fall within the scope of the appended claims. For example, although the above embodiments have been described in the context of TIN data or pre-processed data constituting a conversion from grid cell data to TIN data, the skilled person should appreciate that the processor 202, for example the map data generator 290, can be arranged to generate TIN data from grid cell or other suitable polygonal data in real-time or near real-time. Whilst embodiments described in the foregoing detailed description refer to GPS₁ it should be noted that the navigation device may utilise any kind of position sensing technology as an alternative to (or indeed in addition to) GPS. For example the navigation device may utilise using other global navigation satellite systems such as the European Galileo system. Equally, it is not limited to satellite based but could readily function using ground based beacons or any other kind of system that enables the device to determine its geographic location.

Alternative embodiments of the invention can be implemented as a computer program product for use with a computer system, the computer program product being, for example, a series of computer instructions stored on a tangible data recording medium, such as a diskette, CD-ROM, ROM, or fixed disk, or embodied in a computer data signal, the signal being transmitted over a tangible medium or a wireless medium, for example, microwave or infrared. The series of computer instructions can constitute all or part of the functionality described above, and can also be stored in any memory device, volatile or non-volatile, such as semiconductor, magnetic, optical or other memory device.

It will also be well understood by persons of ordinary skill in the art that whilst the preferred embodiment implements certain functionality by means of software, that functionality could equally be implemented solely in hardware (for example by means of one or more ASICs (application specific integrated circuit)) or indeed by a mix of hardware and software. As such, the scope of the present invention should not be interpreted as being limited only to being implemented in software. Lastly, it should also be noted that whilst the accompanying claims set out particular combinations of features described herein, the scope of the present invention is not limited to the particular combinations hereafter claimed, but instead extends to encompass any combination of features or embodiments herein disclosed irrespective of whether or not that particular combination has been specifically enumerated in the accompanying claims at this time.

Claims

1. A navigation apparatus comprising: a processing resource operably coupled to a data store, the data store comprising terrain data relating to a three-dimensional terrain and feature data associated therewith; a location determination unit operably coupled to the processing resource and capable of determining a location; a display device operably coupled to the processing resource, the processing resource supporting, when in use, a view generation engine and the display device being capable of receiving output data generated by the view generation engine; wherein the terrain data is arranged as a network of triangular cells comprising a triangular cell having respective height data associated with each vertex thereof, the triangular cell being relevant to the location; the feature data comprises information concerning a feature relevant to the location; and the processing resource is arranged to access, when in use, a part of the terrain data and a part of the feature data relevant to the location, and the view generation engine is arranged to represent in planar form the triangular cell and the feature relative thereto.

2. An apparatus as claimed in Claim 1 , wherein the network of triangular cells is a Triangulated Irregular Network.

3. An apparatus as claimed in Claim 1 , wherein the network of triangular cells comprises another triangular cell located adjacent the triangular cell and having a height associated with a vertex thereof and sharing remaining vertices with the triangular cell.

4. An apparatus as claimed in Claim 3, wherein a common boundary at least notionally extends between the shared remaining vertices.

5. An apparatus as claimed in Claim 4, wherein the common boundary is substantially indicative of a convergent height.

6. An apparatus as claimed in Claim 5, wherein the processing resource is arranged to represent at least part of the feature at a height relative to the triangular cell and the another triangular cell.

7. An apparatus as claimed in Claim 6, wherein the height of the at least part of the feature is determined using the convergent height.

8. An apparatus as claimed in Claim 7, wherein the processing resource is arranged to provide a first node and a second node in relation to the at least part of the feature, the first node and the second node being indicative of limits of the at least part of the feature with respect to overlap with the triangular cell and/or the another triangular cell; and the first node and the second node have respective node heights associated therewith substantially equal to the convergent height.

9. An apparatus as claimed in any one of Claims 3 to 8, wherein the height data respectively associated with the shared remaining vertices are substantially the same.

10. An apparatus as claimed in any one of the preceding claims, wherein the feature data comprises road data.

11. An apparatus as claimed in any one of the preceding claims, wherein the feature data comprises land use data.

12. An apparatus as claimed in any one of the preceding claims, wherein the view generation engine is arranged to colour at least part of the planar representation of the triangular cell in accordance with a height-related colour scheme.

13. An apparatus as claimed in Claim 12, wherein the height-related colour scheme comprises a palette of colours associated with a range of heights.

14. An apparatus as claimed in Claim 12 or Claim 13, wherein the height-related colour scheme comprises a plurality of height sub-ranges, each height sub-range of the plurality of height sub-ranges being associated with a colour.

15. An apparatus as claimed in Claim 12 or Claim 13 or Claim 14, wherein the height-related colour scheme is user-defined.

16. An apparatus as claimed in Claim 15, when dependent upon Claim 13 or Claim 14, wherein the processing resource is arranged to permit a first colour to be set in respect of a first height sub-range substantially at a first end of the range of heights and a second colour to be set in respect of a second height sub-range substantially at a second end of the range of heights, and to determine colours of the palette in respect of height sub-ranges between the first and second height sub-ranges.

17. An apparatus as claimed in Claim 16, wherein the processing resource is arranged to permit an intermediate colour to be set in respect of a height between the first and second ends of the range of heights and to determine colours of the palette between the first and intermediate colours and the intermediate and second colours.

18. A navigation system comprising: a navigation apparatus as claimed in any one of the preceding claims; wherein the data store is remotely located from the navigation apparatus and accessible via a communications network.

19. A method of generating a view to be displayed by a navigation apparatus, the method comprising: determining a location associated with the navigation apparatus; accessing a part of terrain data and a part of feature data relevant to the location, the terrain data being arranged as a network of triangular cells comprising a triangular cell relevant to the location and having respective height data associated with each vertex thereof, and the feature data comprising information concerning a feature relevant to the location; and representing in planar form the triangular cell and the feature relative thereto.

20. A navigation apparatus comprising: a processing resource operably coupled to a data store, the data store comprising terrain data relating to a three-dimensional terrain; a location determination unit operably coupled to the processing resource and capable of determining a location; a display device operably coupled to the processing resource, the processing resource supporting, when in use, a view generation engine and the display device being capable of receiving output data generated by the view generation engine; wherein the terrain data is arranged as a network of polygonal cells comprising a polygonal cell having respective height data associated with each vertex thereof, the polygonal cell being relevant to the location; and the processing resource is arranged to access, when in use, a part of the terrain data relevant to the location, and the view generation engine is arranged to represent in planar form the polygonal cell, the representation comprising colouring at least part of the planar representation of the polygonal cell in accordance with a height-related colour scheme.

21. An apparatus as claimed in Claim 20, wherein the height-related colour scheme comprises a palette of colours associated with a range of heights.

22. An apparatus as claimed in Claim 20 or Claim 21 , wherein the height-related colour scheme comprises a plurality of height sub-ranges, each height sub-range of the plurality of height sub-ranges being associated with a colour.

23. An apparatus as claimed in Claim 20 or Claim 21 or Claim 22, wherein the height-related colour scheme is user-defined.

24. An apparatus as claimed in Claim 23, when dependent upon Claim 21 or Claim 22, wherein the processing resource is arranged to permit, a first colour to be set in respect of a first height sub-range substantially at a first end of the range of heights and a second colour to be set in respect of a second height sub-range substantially at a second end of the range of heights, and to determine colours of the palette in respect of height sub-ranges between the first and second height sub-ranges.

25. An apparatus as claimed in Claim 24, wherein the processing resource is arranged to permit an intermediate colour to be set in respect of a height between the first and second ends of the range of heights and to determine colours of the palette between the first and intermediate colours and the intermediate and second colours.

26. A method of representing a terrain by a navigation apparatus, the method comprising: determining a location of the navigation apparatus; accessing a part of terrain data relevant to the location, the terrain data being arranged as a network of polygonal cells comprising a polygonal cell having respective height data associated with each vertex thereof, the polygonal cell being relevant to the location; representing the polygonal cell in planar form; and colouring at least part of the planar representation of the polygonal cell in accordance with a height-related colour scheme.

27. A computer program element comprising computer program code means to make a computer execute the method as claimed in Claim 19 or Claim 26.

28. A computer program element as claimed in Claim 27, embodied on a computer readable medium.

29. A data store of a navigation apparatus comprising terrain data, the terrain data being arranged as a network of triangular cells comprising a triangular cell having respective height data associated with each vertex thereof.