WO2005098362A1

WO2005098362A1 - Navigation system and method

Info

Publication number: WO2005098362A1
Application number: PCT/GB2005/001105
Authority: WO
Inventors: Matthew Faulk
Original assignee: The Secretary Of State Acting Through Ordnance Su Rvey
Priority date: 2004-04-05
Filing date: 2005-03-24
Publication date: 2005-10-20
Also published as: GB2413021B; GB2413021A; GB0407759D0

Abstract

A mobile device or mobile client device is operate to monitor its position using a positioning device such as a global positioning device and to display an visual representation of a landmark (in the correct orientation) in response to a determination that the device has entered or exited a geographical zone. The visual representation aids navigation of a user traversing a route to a geographical destination. An itinerary inclining the route to be traversed as well as one or more geographical zones and visual representations of landmarks may be automatically prepared by the device or at a server using information inputted by the user regarding the destination and a starting point such as a present geographical position of the device as determined by the positioning device.

Description

NAVIGATION SYSTEM AND METHOD

BACKGROUND OF THE INVENTION This invention relates to a navigation system and method.

When a person is travelling in an area which is well known to him, he will generally be able to form a cognitive map for navigating in that area. When navigating in an unfamiliar area, a person may not be able to form such a cognitive map and may need to refer to a map such as a paper or electronic map. To use the map, the person should be able to relate the information on the map to his immediate surroundings while navigating.

A person travelling from a starting point to a destination may also operate by moving from one known landmark to the next, until he reaches his destination. In areas in which a user is unfamiliar with the available landmarks, this method of navigating can be unreliable.

Global Positioning Systems (GPS) enable the position of a GPS receiver to be determined to a high degree of accuracy. The user of a GPS system can thereby locate himself on a paper or electronic map as described above. Some GPS receivers, such as those found in cars, are able to provide a user with travel instructions based upon the determined position. Instructions of this kind can be useful. However, they are sometimes difficult to follow, especially where a route involves many closely spaced turnings. The instructions may also be difficult to follow because the user must constantly make a linlc between the instructions and his surrounding environment. There is no way for the user to verify that the instructions do indeed relate to his immediate surroundings and this can lead to misinterpretation of instructions.

Accordingly, this invention seeks to provide a system and method for aiding navigation, which does not suffer from the problems indicated above. Furthermore, this invention seeks to provide a system and method for aiding navigation, which can be implemented using a minimum of resources on a mobile device and which requires a minimum of bandwidth for server-client communications where the device is a mobile client.

SUMMARY OF THE INVENTION

Particular and preferred aspects of the invention are set out in the accompanying independent and dependent claims. Combinations of features from the dependent claims may be combined with features of the independent claims as appropriate and not merely as explicitly set out in the claims.

An aspect of the invention provides a mobile device including a processor, memory, a display, a positioning device and a user input. The mobile device is operable to monitor a geographical position of the mobile client device using the positioning device. The mobile device is also operable to respond to a determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark by accessing and displaying a visual representation of the landmark on the display. The visual representation can be a pictorial representation of the landmark, for example a representation formed by or derived from one or more photographs, video sequences, graphical representations, etc. Displaying visual representations of landmarks on a mobile client device aids navigation. The invention includes a mechanism by which an appropriate time or place to display a visual representation of a given landmark can be determined.

The mobile device can be a mobile client device, and can include a transmitter and a receiver for communicating with a server via a communications network. According to some embodiments, to plan a route, a user can enter data describing a geographical destination into the mobile client device using the user input. The mobile client device can then transmit the data describing the destination to the server along with data describing a geographical starting point. The geographical starting point may be user selected or may by default (for example) be the present geographical position of the mobile client device determined by the positioning device. The mobile client device can receive data describing an itinerary from the server, the itinerary including a route from the starting point to the destination and the geographical zone, as well as the appropriate landmark's views.

The mobile device can be operable to display a map on the display along with a representation of the monitored geographical position. The map can be updated using data received from a server. A representation of the geographical zone can also be displayed on the map.

According to some embodiments, the determination that the mobile client device has passed through the boundary of the geographical zone may be made at the mobile client device. The mobile client device can then send a request for a visual representation of the landmark to the server. The mobile client device can also be operable to pre- request and store visual representations and/or other navigation information. The visual representation of the landmark can be displayed in response to a determination that the mobile client device has entered the geographical zone. Alternatively, the visual representation of the landmark can be displayed in response to a determination that the mobile client device has exited the geographical zone, the landmark being a next landmark on the route.

The displayed visual representation can be selected from a group of candidate visual representations of a particular landmark. Selection criteria can include the monitored geographical position of the mobile client device and/or a tracking vector based upon a plurality of monitored geographical positions of the mobile client device and/or which boundary of the geographical zone the mobile client device is determined to have passed through.

Further visual representations of the landmark can be displayed in response to user input (for example by dragging on a touch-screen display). The itinerary can include a further geographical zone associated with the landmark and the mobile client device can respond to a determination that the mobile client device has passed through a boundary of the further geographical zone associated with the landmark by accessing and displaying a visual representation of the landmark. The further geographical zone associated with the landmark can be a buffer zone for reducing the number of calculations required to determine whether a boundary has been passed through.

The itinerary can include a further geographical zone associated with a further landmark. The further landmark may be another landmark on the route or may be a negative landmark, that is a landmark indicative that the user has deviated from the planned route.

The determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark can be made by comparing the monitored geographical position of the mobile client device with geographical positions within the geographical zone.

The route can be represented by a series of vectors.

The monitored geographical position of the mobile device can be resolved onto the vectors to reduce the determination of whether a boundary has been passed through to a one-dimensional problem. The geographical zones described herein can be represented by a polygon in two or more dimensions.

The mobile device can be operable to output at least one of textual and audible navigation information regarding the itinerary to the user.

The positioning device can be a global positioning device. Another aspect of the invention provides system which includes a server that is operable to receive, from a mobile client device of the kind described above, data describing a geographical destination and a geographical starting point. The server is also operable to use the data received from the mobile client device to prepare an itinerary for the mobile client device. The itinerary includes a route from the starting point to the destination and geographical zone associated with a landmark. The server is further operable to transmit data describing the itinerary to the mobile client device. The server is also operable to respond to a determination that the mobile client device has passed through a boundary of a geographical zone by transmitting a visual representation of the landmark to the mobile client device.

The server can be operable to monitor the geographical position of the mobile client device using positioning data received from the mobile client device. The server can thereby determine whether the mobile client device has passed through a boundary of the geographical zone.

The server can be operable transmit a visual representation of the landmark to the mobile client device on request by the mobile client device.

The visual representation to be transmitted to the mobile client device can be selected from a group of candidate visual representations of a particular landmark. Selection criteria can include the monitored geographical position of the mobile client device and/or a tracking vector based upon a plurality of monitored geographical positions of the mobile client device and/or which boundary of the geographical zone the mobile client device is determined to have passed through.

A further aspect of the invention provides a method of providing navigational information on a mobile device. The method includes monitoring a geographical position of the mobile device using a positioning device of the mobile device. The method also includes the mobile device responding to a determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark by accessing and displaying a visual representation of the landmark on a display of the mobile device. Where the mobile device is a mobile client device, accessing the visual representation can include transmitting to a server via a communications network a request for a visual representation of the landmark, and the mobile client device receiving a visual representation of the landmark. The method can further include a server receiving from a mobile client device data describing a geographical destination and a geographical starting point. The server can use the data received from the mobile client device to prepare an itinerary for the mobile client device. The itinerary can include a route from the starting point to the destination and a geographical zone associated with a landmark. The method can further include the server transmitting data describing the itinerary to the mobile client device. The method can also include the server responding to a determination that the mobile client device has passed through a boundary of a geographical zone by transmitting a visual representation of the landmark to the mobile client device. Another aspect of the invention provides a computer program product for implementing the methods described above. For example, a computer program product can be executable on a mobile device or a server to cause the mobile device or server to become operable to perform the respective methods described above. A computer program product for implementing the invention can 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 indeed any other transmission medium. Further aspects and advantages of the invention will become apparent from the following description of particular embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present invention will be described hereinafter, by way of example only, with reference to the accompanying drawings in which like reference signs relate to like elements and in which:

Figure 1 shows a system including a number of mobile client devices linked to a server via a network; Figure 2 shows a schematic of the functional components of a mobile client device in accordance with an example of the invention; Figure 3 shows a schematic of the functional components of a server in accordance with an example of the invention; Figure 4 shows a geographical area with a starting point, a destination, and a route from the starting point to the destination in accordance with an example of the invention; Figure 5 shows a geographical area with landmark and a two-dimensional geographical zone in accordance with an example of the invention; Figure 6 shows an example of a three-dimensional geographical zone in accordance with an example of the invention; Figure 7 provides an example of a geographical zone for illustrating a data structure for representing the zone; Figure 8 shows a geographical area with a landmark, a route and a geographical zone in accordance with an example of the invention; Figure 9A shows illustrates a way in which a visual representation of a landmark can be selected according to the direction of travel of a user of a mobile device or mobile client device; Figure 9B shows illustrates a way in which a visual representation of a landmark can be selected according to the boundary of a geographical zone which a mobile device has been determined to have passed through; Figure 10 shows an example of how a monitored geographical position of a user can be resolved onto a vector to reduce the calculations required to implement embodiments of the invention; Figure 11 shows an example of how buffer zones can be used to reduce the calculations required to implement embodiments of the invention; Figure 12 illustrates an example of navigation between a starting point and a destination in accordance with a selected route and the use of negative landmarks for directing user back to a correct route; Figure 13 shows a geographical area with first and second landmarks, a route and a geographical zone in accordance with an example of the invention; Figure 14 illustrates one example of the use of multiple geographical zones for a single landmark; Figure 15 shows an example of a display output on a mobile device or mobile client device in accordance with an example of the invention; Figures 16A and 16B show an example of a three-dimensional visual representation; Figure 17 shows a flow chart illustrating a method in accordance with an example of the invention; and Figure 18 shows another flow chart illustrating a method in accordance with an example of the invention; and Figure 19 shows a further flow chart illustrating a method in accordance with an example of the invention; and Figure 20 shows a further flow chart illustrating a method in accordance with an example of the invention; and Figure 21 shows another flow chart illustrating a method in accordance with an example of the invention; Figure 22 illustrates an example operation with respect to Figure 7.

While the invention is susceptible to various modifications and alternative forms, specific embodiments are shown by way of example in the drawings and are 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 claimed invention. DESCRIPTION OF PARTICULAR EMBODIMENTS

Embodiments and examples are described hereafter by way of example only in the following with reference to the accompanying drawings.

Figure 1 represents a schematic overview of a system which includes a number of mobile client devices 14, 16, 18, 20 connected to a server 12 via a network 10. The mobile client devices shown in this example are a PDA 14, a mobile phone 16, a portable computer 18 such as a laptop computer and a client device provided in vehicle such as a car, van or truck. In some of the particular examples to be described, it is assumed that the network 10 is made up of a radio telephony network (e.g., a mobile or cellular telephone network), and that each of the mobile client devices shown include a transmitter/receiver connectable to the mobile telephone network. Figure 2 provides a schematic overview of the functional components of a mobile client device 28 such as one of those represented in Figure 1. As shown in Figure 2, these functional components include a display 30, a user input 32 (which can include keypad and/or a touch screen display) and an aerial 34. They also include a processor 36 which co-operates with a display driver 38 for controlling the display 30, a memory 40 for storing data 39 and program code 41, and a communications interface 42 for interfacing with the aerial 34. The functional components further include a positioning device 44 for determining a geographical position of mobile client device. In some examples, the positioning device 44 is a global positioning device. The processor 36, display driver 38, memory 40 and communications interface 42 can be provided by one or more integrated circuits represented generally at 46. At least a portion of the positioning device 44 may also be included in the circuitry 46.

Figure 3 provides a schematic overview of the functional components of an example of a server 12 in the form of a computer system. As is shown in Figure 3, these functional components include a processor 50 and memory 52. Storage 54 may be provided for storing large quantities of information such as map data and/or visual representations of landmarks. The storage 54 may for example include a hard disk drive, CD-ROM and/or other mass storage devices. One or more peripheral devices such a keyboard and monitor 56 may be provided. The server 12 can also include a communications interface 58 for interfacing with the communications link 60. The server is thereby connectable to a network such as that discussed in relation to Figure 1.

Embodiments of the invention can provide a navigation system and method. The navigation system and method can be used to facilitate navigation to a destination by displaying visual (e.g., pictorial) representations of landmarks on a mobile device (such as a mobile client device). Embodiments of the invention allow the visual representations to be displayed at appropriate times, according to factors such as the geographical position of the mobile device or the direction of travel of the mobile device. Audible and/or textual information such navigational instructions and/or information regarding the landmarks (for example historical information of interest to a tourist) may also be output in conjunction with the visual representations.

Before describing example embodiments of the invention in more detail, examples of the methodology applied by embodiments of the invention will be described in more general terms.

Figure 4 shows a geographical area 100. The area 100 may contain a large number of geographical features, but for simplicity only the main roads 105 in the area are shown, as well as a number of landmarks 124, 122 as will be described below. It is assumed that a user of a mobile device wishes to travel from a starting point 110 to a destination 120.

An itinerary including a route from a starting point 110 to a destination 120 can be determined from the starting point and destination. One such route 130 is shown as the dashed line in Figure 4. On the route 130, there may be a number of entities such as particular buildings (churches, particular shops, buildings with unusual architectural features, etc.) or geographical features (hills, bridges, roundabouts, etc.) that may be suitable as landmarks to aid navigation. One or more landmarks on the route 130 may be chosen and one or more visual representations of each landmark may displayed on a mobile device at appropriate times, so as to aid a user in navigating from the starting point 110 to the destination 120. As described below, textual and/or audible information may also be output by the mobile device, in conjunction with the visual representation. Visual representations of landmarks may also be displayed and textual/audible information may also be outputted by way of providing the user with information regarding the landmarks. For example, the mobile device can provide the user with information that may be of interest to a tourist (eg architectural and/or historical information).

In some examples, the route between a starting point and a destination are determined and then an itinerary for a journey between the two is prepared. As will be described below, in different example embodiments of the invention, the itinerary may be prepared either at the mobile device or at a server using information received from the mobile client device. The itinerary can include a route between the starting point and the destination.

Many factors may influence the determination of a route. Examples of such factors include a shortest distance between a starting point and a destination and/or the shortest anticipated travel time. In such examples, landmarks can be chosen according to the selected route. In other examples, the choice of route itself may be influenced by the existence of prominent landmarks in the local area. For example, a slightly longer route may be selected on the basis that better landmarks can be provided to ease navigation, or to provide a route of specific interest to a user. Factors for route selection can include the mode of transport of the user, user specific characteristics such as age and physical health, temporal factors such as the time of day, the time of year, information regarding traffic conditions and so forth. Such information can be input into the mobile device and can then be used in the determination of an appropriate route.

Landmarks which serve different navigational purposes can be selected. Some examples of these are described below.

Some landmarks can be selected to confirm to the user that he is heading in the correct direction. For example, a landmark on a long straight road may confirm to a user that he is on the correct road.

Other landmarks can be selected to indicate a point at which a change in direction should be taken. For example, a visual representation of a particular restaurant on a corner of a crossroads may be selected in conjunction with instructions such as "turn left at the restaurant".

A further type of landmark can be selected when a user has strayed from a selected route. In the following, these types of landmark are referred to as negative landmarks. Where a user has taken the wrong route, a visual representation of a negative landmark lying away from the selected route can be displayed along with a message indicating that the wrong route has been taken. In some examples, a visual representation of a landmark for correcting the route or associated with a recalculated route can be displayed.

Some landmarks may not be associated with navigation as such. As described herein, some landmarks may be included in a route due to their interest to the user. For example the user may be a tourist traversing a route from a starting point to a destination, the route having a number of landmarks (tourist attractions) along the way.

In the example shown in Figure 4, two landmarks 122 and 124 have been selected. In this example, both landmarks are buildings located on corners and serve to indicate a change in direction. When travelling from the starting point 110 to the destination 120, the user is to be directed to make a left turn at each of the selected landmarks 122 and 124. While only two landmarks are shown in Figure 4, any number of landmarks may in fact be selected as appropriate.

As described above, visual representations of the selected landmarks 122, 124 may be displayed at appropriate times on the journey. An appropriate time may be as the user is approaching a landmark and/or when it is anticipated that the landmark has come into sight. A mechanism for determining the visual extent of a landmark will be now described with reference to Figure 5.

Figure 5 shows a geographical area 150 within which three roads 152, 154 and

156 meet at a T-junction. On a corner of the junction are three buildings 170, 172 and

174. Also shown in Figure 5 is a geographical zone 160. The geographical zone 160 in this example is enclosed by a series of boundaries 164, which are shown Figure 5 as dotted lines. The boundaries are linked by a number of nodes 162.

As used herein, the term "geographical zone" refers to a corporeal object, namely a zone such as an area or volume in physical space. The term "geographical zone" does not refer merely to a mathematical construct that resides only in the memory of a computer. Similarly, the term "geographical position" as used herein refers to the position of a corporeal object (such as a mobile device) in physical space. The term "geographical position" does not refer merely to a mathematical construct that resides only in the memory of a computer. Nevertheless, it will be understood that geographical zones and geographical positions may be represented mathematically in the memory of a computer, whereby determinations regarding the geographical position and the geographical zone can be made.

In this example, the geographical zone is associated with the building 1 0 and corresponds to the visual extent of the building 170. The building is generally visible from geographical positions within the geographical zone, but is not generally visible from geographical positions outside the geographical zone. By monitoring the geographical position or direction of motion of a user of a mobile device relative to the geographical zone 160 and/or the boundaries 164 thereof, it is possible to determine whether the building 170 is visible to the user, or indeed whether the building is about to become visible or go out of sight.

The generation of the zones associated with landmarks can depend on a number of factors, including, for example, one or more of: - building height; - height of neighbouring features (fences, walls, hedges); - cultural importance (e.g. Church); - position (e.g. corner property); - architecture - e.g., colour, texture, facade, roof type, year of build, period; - land use; - presence of unusual traits (e.g. turrets?) - type, styles, etc of the architecture of surrounding properties.

Geographical landmark zones will thus be constrained by the character of the object as well as its immediate surroundings.

When defining geographical zones to accompany landmarks, a general rule of thumb can be that, the more distinctive the feature, the more extensive its zone. For example, a distinctive building on a corner of a major street can be seen for many hundreds of metres up the road because of its distinctive features, could have a large geographical zone associated with it. A more common-place landmark within a typical urban environment could have a more compact type geographical zone associated with it.

The shape and extent of the geographical zone can also depend upon the geographical environment surrounding the building 170. For example, objects such as others buildings located in the vicinity of the building 170 may obscure the building 170 from view from certain positions. In the example shown in Figure 5, the buildings 172 and 174 located next to the building 170 obscure the building 170 to different extents. Considerations of these types are which are used to determine the shape of geographical zone 160 according to the visual extent of a landmark. For a user who is approaching the building 170 along a direction shown generally by the arrow labelled 'B' in Figure 5, the building 174 obscures the building 170 from view until the user is relatively close to the building 170. Accordingly, the boundary the user approaches when travelling along the direction indicated by arrow 'B' does not extend very far along the road 154. This may reflect the fact that the building 174 is much taller than the building 170 and/or that the building 170 is set back farther from the road 154 than is the building 174.

In contrast, the building 172 does not obscure the building 170 from view to such an extent. The building 172 may be shorter and/or generally smaller than the building 170 and or set back from the road 152, whereby the building 170 is generally more visible from positions along the road 152. Accordingly, for a user travelling along the road 152 in the direction indicated in Figure 5 by the arrow labelled 'C, the building 170 will tend to come into view earlier than for a user approaching the building along the direction indicated by the arrow labelled 'B'. This is reflected by the fact that the geographical zone 160 extends further from the junction along the road 152 than it does along the road 154. For a user travelling along the road 156, the view of the building 170 is generally obscured by buildings or other features lying on the corner of the roads 152 and 156. Three-dimensional geographical zones may also be used. Figure 6 shows an example of portion of a three-dimensional geographical zone. The geographical zone 160 shown in Figure 6 is associated with the building 174 and has been determined according to the building's 174 visual extent. For clarity, the entire of the geographical zone 160 is not shown in Figure 6, but it generally surrounds the building 174 in three dimensions and encompasses any point in space from which the building 174 is visible. The geographical zone 160 may have an upper height limit. In Figure 6, the building 170 stands close to the building 174 and will obscure the building 174 from sight from certain positions. In particular, the volume of space 166 encompasses all points from which the building 174 is obscured by the building 170. The boundaries between the geographical zone 160 and the volume 166 are defined by the surfaces marked out by the dotted lines in Figure 6.

Three-dimensional geographical zones can be of use in situations where the height of a user is important. For example, a user travelling in a bus, receiving tourist information is at a different elevation to a user who is travelling by foot. The visual extent of a building changes with height, and three-dimensional geographical zones can take account of this.

Other factors may be used to determine the shape and extent of the geographical zone. Examples of such factors include a limit on the extent of the geographical zone in terms of surface distance and/or height. While there may be a direct line of sight between a user and a feature, the feature may be too distant to view usefully (identify) over a certain distance. In another example, the number of nodes in the zone may be limited so as to avoid the -shape of the geographical zone becoming overly complex. In some implementations, the geographical zone may extend further than the true visual extent of a feature, thereby allowing some lead time for the system and/or user to react to the building coming into view. The shape and extent of a geographical zone may also be enhanced (increased) according to the predominance/significance of a building.

Mathematically, the two-dimensional geographical zones described herein can be represented by a series of nodes located in an X-Y plane (for example, 'X' may represent a longitude and 'Y' a latitude) and linked by a series of boundary vectors to make a two- dimensional polygon. The geographical position of a user in terms of, for example, a longitude and a latitude can be determined by a positioning device such as a global positioning device and mapped onto the X-Y plane. By monitoring the position of the user in this way, it is possible to determine when a user carrying a mobile device crosses one of the boundaries. Figure 7 illustrates an example of a geographical zone and Tables 1 below illustrates an example of a data structure for representing the geographical zone. In this example, a geographical zone comprises a polygon having series of X,Y coordinates defining nodes N with, between the nodes, a series of lines, or edges E. The series of edges have a common start and end location (as a single node), whereby the polygon is formed by a closed loop of edges.

The topology of the structure is that the edges have both a start and end point at respective nodes, with the coordinates of the nodes defining the shape of the polygon and the connections between the nodes forming the structure of the polygon. Each of the edges of the polygon representing a geographical zone is associated with respective attributes. A data structure is used to represent the geographical zones in an embodiment of the invention. Any suitable form of data structure, such as a table-based structure, a file- based structure or an object-based structure, or a combination thereof, could be used. Table 1 below illustrates a table-based structure by way of example only. In Figure 7, a five sides polygon PI representing a geographical zone for a landmark LI is shown. The polygon PI encompasses the landmark LI and a threshold zone Zl outside the landmark. In an embodiment of the invention, each landmark can have a unique identifier (for example LI, L2 , L3, etc.). Each geographical zone can also be given a unique identifier (e.g., PI, P2, P3, etc). In the present example the same numerical value (1) is given to the landmark LI and the geographical zone PI, although this need not be the case.

The geographical zone PI has 5 sides, or edges (E1-E5), which are joined by 5 nodes Nl - N5. Each edge is defined as a vector between two nodes. For example edge El is defined as extending from node Nl to node N2. In the case of edge E5, a '6^th node is formed by Node Nl, i.e. a node having the same coordinates as the "from" node of edge El, indicating that the loop is closed. Each edge E1-E5 has a separate set of attributes.

Table 1 below illustrates a tabular representation of attributes of the edges for polygon PI.

TABLE 1

EDGE F NODE T NODE LPOLY# RPOLY# IMAGE

El Nl N2 P0 PI LI VI

E2 N2 N3 PO PI L1.V2

E3 N3 N4 P0 PI L1.V3

E4 N4 N5 P0 PI L1.V4

E5 N5 Nl PO PI L1.V5

It will be noted that there is a separate table entry for each edge El - E5. Each edge entry identifies a "from" node (F NODE) and a "to" node (T NODE) defining the direction of the vector forming the edge. The coordinates of the respective nodes N can be held in the table of Table 1, or the representations Nl, N2, N3, etc, can form links to a separate table holding the respective X and Y coordinate values for the nodes.

For each edge, an LPoly# field provides an ID number for a polygon to the left of an edge with respect to the direction of the vector from the "from" node to the "to" node. As, in the present instance the nodes are joined up in a clockwise direction, LPoly# defines the outside of the geographical zone (here designated P0). Similarly, for each edge, an RPoly# field provides an ID number for a polygon to right of an edge with respect to the direction of the vector from the "from" node to the "to" node. As, in the present example, the nodes are joined up in a clockwise direction, RPoly# defines the inside of the geographical zone (in Figure 7, polygon PI). The LPoly# and RPoly# can be used in an example of the invention to determine when a geographical zone is being entered. For example it can be deduced that the user is inside geographical zone PI when the edge El is crossed from the left to the right across the edge El, namely that the user has moved from PO to PI . For each edge, an Image field provides a link to a file that holds a visual representation to be displayed when a user crosses into the polygon PI across the edge concerned. The link could, for example, be a file pathname that points to the visual representation associated with that edge. The visual representation could be in the form of a Virtual Reality Modeling Language (VRML) image (3D), a sketch or photograph as a Joint Photographic Experts Group (JPEG) image, etc. The different visual representations will provide an appropriate view of the landmark as would be seen from the appropriate direction. For example, for the landmark LI, the edges might equate to the following views:

El = LI .VI =View 1 (from the West)

E2 = LI N2 = View 2 (from the North)

E3 = LI V3 = View 3 (from the East)

E4 = LI N4 = View 4 (from the East)

E5 = LI V5 = View 5 (from the South)

It will be appreciated that other attributes can be included according to a particular implementation. For example, where three-dimensional geographical zones are used, a Z values will represent a height on a two-dimensional surface (see Figure 6).

These surfaces will have edges and will contain attributes including or providing a link to an appropriate image file. The boundaries of three-dimensional geographical zones are two-dimensional surfaces.

Figure 7 also illustrates a number of points identified by the numerals 1 - 9. These are referred to later with reference to the description of Figure 22. For further information and examples relating to the determination of boundary crossing, the reader is referred to the following reference: 'Principles of Geographical Information Systems (Spatial Information Systems and Geostatistics)', by Peter A. Burrough and Rachel A McDonnell, published by Clarendon Press. In particular, one such algorithm, which could be used to implement boundary crossing determination, is know as the "point-in-polygon search". The point-in-polygon search is described in this reference.

To calculate the visual extent of a landmark for use in calculating a geographical zone, data from a database such as Ordnance Survey's MasterMap (RTM) may be used. The OS MasterMap is a large-scale geospatial database in which real world features are represented as polygons. The OS MasterMap thus comprises data relating to the position and dimensions of real world features such as buildings. Spatial algorithms can be applied to this data to calculate the visual extent of a landmark based upon the dimensions and position of a landmark and upon the dimensions and position of other real world features in the vicinity. By applying spatial algorithms of this kind, geographical zones of the type described above can be prepared for a large number of landmarks. The landmarks themselves may be pre-selected based upon factors such as visual prominence, local significance, historic significance, matter of interest (for example, to tourists), suitability of location (such as on a main road or at a junction) and so forth. This process can be performed on demand, once a route has been selected. Alternatively, geographical zones can be pre-calculated and stored in readiness for selection in conjunction with a selected route as part of an itinerary. A database such as the OS MasterMap can also be used to provide map data in a mobile device as described below.

Thus there has been described a mechanism by which geographical zones can be calculated according to factors such as the visual extent of a geographical feature such as a building as well as other, non- visual factors. The geographical position of a user with a mobile device can be monitored by a positioning device, for example a global positioning systems (GPS) device of the mobile device. The monitored geographical position may include (or be derived from) GPS log data. The monitored position can be used to determine an appropriate time or place along a route taken by the user to display on the mobile device a visual representation of a given landmark. One example of this process is now described in relation to Figure 7.

Figure 8 shows a portion of the geographical area 100 shown in Figure 4, centred around one of the landmarks 124, which has been selected as a landmark on the route 130 from the starting point 110 to the destination 120. Also shown in Figure 8 is a geographical zone 180 associated with the visual extent of the landmark 124, which in this example is a shop building. The route 130 is represented in Figure 7 by a dashed line. For the purposes of this example, it is assumed that in following the route 130, the user has previously navigated to the portion of the geographical area 100 shown in Figure 8 and is approaching the landmark 124 in the direction represented by the arrow labelled 'D'. As described above, the geographical position of the user is monitored by a positioning device of a mobile device carried by the user. As will be described below, the mobile device or a server with which the mobile device can communicate via a communications network can use the monitored geographical position to determine when the mobile device (and therefore the user) has passed through a boundary of the geographical zone 180. Given the direction of travel of the user shown by the arrow labelled 'D', this will occur at or near to the point 194.

In Figure 8, the series of 'X's which lies along the route 130 correspond to a number of geographical positions of the mobile device as monitored. The monitored positions may be determined in accordance with GPS log data. Each monitored position can be compared with positions that lie within the geographical zone 180. As the user approaches the geographical zone 180, it can be determined that the monitored position (for example the monitored position 190) as recorded in a GPS log does not lie within the geographical zone 180. When the user passes through the boundary of the geographical zone 180, the next monitored position after monitored position 190 (namely monitored position 192) will be determined to lie within the geographical zone 180. Accordingly, it can be determined that the user has passed through a boundary of the geographical zone 180.

Once it is determined that the boundary has been passed, the mobile device can respond by retrieving a visual representation of the landmark 124 and displaying the visual representation on a display of the mobile device. As will be described in more detail below, the visual representation may be stored locally or it may be retrieved, via a communications network, from a server. As described above, in some implementations, the geographical zone may extend further than the actual visual extent of the landmark 124. This provides a delay between the determined crossing of the geographical zone 180 and the landmark 124 actually becoming visible. The delay can be used to accommodate client-server communications and/or any local processing which is associated with retrieving and displaying a visual representation of the landmark 124. Also, in some examples, it may be desirable to display a visual representation of the landmark 124 prior to the landmark actually coming into view, so as to provide the user with a prompt to begin looking for the landmark.

In conjunction with the displayed visual representation, the mobile device may also output navigation information such as instructions for action to be taken once the landmark has been sighted. The information can, for example, be textual (displayed on the display) and/or audible. In the present example, instructions are outputted to turn left at the corner on which the landmark 124 lies. This enables the user to correctly navigate the selected route 130.

In some examples, there may be more than one visual representations of the landmark 124 available for retrieval and display. In such cases, a first visual representation to be retrieved and displayed can be selected according to a number of factors. Visual representations of a given landmark may each show a view of the landmark from a different geographical position. Accordingly, in one implementation, the visual representation of the landmark 124, which shows the landmark from a position closest to the monitored geographical position of the mobile device, can be selected.

Another way of selecting a visual representation from a plurality of visual representations of a landmark is now described in relation to Figure 9A. Figure 9A shows a landmark 210 and a geographical zone 220 associated therewith. The geographical zone 220 in this example corresponds to the visible extent of the landmark 210 and has a boundary 222. The landmark 210 in this example is a building having first 212 and second 214 sides.- A number of visual representations of the landmark 210 are available. In particular, one is a visual representation of the landmark 210 showing the side 212, the other is a visual representation of the landmark 210 showing the side 214. When a user carrying a mobile device is determined to have passed through the boundary 222, in this example at point 230, one of the visual representations may be selected in preference to the other for display. To select which visual representation to display, one or more monitored geographical positions of the mobile device can be used to determine the direction of travel of the user as he passes through the boundary 222. The monitored position data may, for example, include GPS log data as described in relation to Figure 7 above. For example, monitored positions at points 232 and 230 would indicate that the user is travelling generally along a direction show by the arrow labelled Ε' in Figure 9A. Accordingly, the visual representation of the side 212 of the landmark 210 may be selected for display since, based on the users direction of travel, it is that side of the landmark 210 which will subsequently be most visible to the user. Alternatively, where monitored geographical positions at points 234 and 230 show the user's direction of travel to be generally in the direction shown by the arrow labelled 'F' in Figure 9 A, the visual representation of the side 214 of the landmark 210 may be selected for display.

A further way of selecting a visual representation from a plurality of visual representations of a landmark is now described in relation to Figure 9B. As described in relation to Figure 9 A, Figure 9B shows a landmark 210 and a geographical zone 220 associated therewith. The geographical zone 220 has a number of boundaries, including boundary 224 and boundary 226. The landmark 210 is a building having first 212 and second 214 sides. A number of visual representations of the landmark 210 are available. As before, one is a visual representation of the landmark 210 showing the side 212, the other is a visual representation of the landmark 210 showing the side 214. Also shown in Figure 9 are a number of monitored positions 230, 232, 234 and 236 of a mobile device. In this example, successive monitored positions are used to determine which boundary of a geographical zone the user has passed through and thereby to select an appropriate visual representation for display. In Figure 9B, where the position of the mobile device is determined at successive monitored positions 230 and 232, this taken to be indicative that the user has passed through the boundary 226 at a point 231 that corresponds to the intersection between the boundary 226 and a line joining the positions 230 and 232. Accordingly, the visual representation of the landmark 210 showing the side 212 is selected for display. Alternatively, where the position of the mobile device is determined at successive monitored positions 234 and 236, this taken to be indicative that the user has passed through the boundary 224 at a point 235 that corresponds to the intersection between the boundary 224 and a line joining the positions 234 and 236. Accordingly, the visual representation of the landmark 210 showing the side 214 is selected for display. A database of visual representations associated with the boundaries of one or more geographical zones can be held either at the mobile device or at a server (for transmission, on request, to a mobile client device). In this way, one or more visual representations can be associated with each boundary of a geographical zone, whereby appropriate views can be selected for display. As described herein, a route between a starting point and a destination may be selected in accordance with data stored in a database such as Ordnance Survey's MasterMap. In particular, an Integrated Transport Network (ITN) layer of MasterMap includes a representation of the road network in the UK. In the ITN layer, the road network is represented as a series of nodes (which represent road junctions) which are linked together by vectors (which represent roads). The ITN layer also includes information regarding temporal traffic flow, and can be used as a data resource for selecting a route according to criteria such as those described below. Furthermore, the nodes and vectors of the ITN layer can be used to represent the route itself. Selection of a route may, for example, include selecting a subset of nodes and vectors from the ITN layer. More information on the OS MasterMap and on the ITN layer thereof can be found at http://www.ordnancesurvey.co.uk/oswebsite/products/osmastermap/itn/.

Figure 10 shows an example of how the monitored geographical position of a mobile device can be resolved along a vector such as a vector in the ITN layer, thereby simplifying the process of determining whether a boundary of a geographical zone has been passed through. Figure 10 shows a landmark 310 by a road 340. The landmark 310 has a geographical zone 320 associated with it. Also shown in Figure 10 is an ITN vector 330, which connects two ITN nodes 332 and 334. Thus, the ITN vector 330 corresponds to a portion of the road 340. Figure 10 also shows a series of crosses 350 which indicate monitored geographical positions of a mobile device according to GPS log data as described above. In this example, each monitored geographical position in the series 350 is resolved onto the ITN vector 330 at 352. In this manner, the determination of whether the mobile device has passed through the boundary of the geographical zone 320 is reduced to a one-dimensional problem. In this example, to determine whether the mobile device is within the geographical zone for the purposes of displaying a visual representation, the monitored geographical position is resolved onto the ITN vector lies within the range of positions on the ITN vector 330 indicated in Figure 8 as the portion 336. The portion 336 corresponds to geographical positions within the geographical zone 320, which coincide with the vector 330. This is less computationally demanding than the two-dimensional problem of comparing a monitored geographical position to a geographical zone in two dimensions. The resolving process described above may also be applied in three dimensions, whereby a monitored geographical position measured in three dimensions can be resolved onto an one dimensional vector such as an ITN vector, thereby significantly reducing the computational effort required to implement embodiments of the invention. An example of another way of reducing the amount of calculations required when determining when to display an appropriate visual representation of a landmark is illustrated in Figure 11. In Figure 11 there is shown a landmark 410 which has a geographical zone 420 associated with it. The geographical zone 420 has a number of boundaries 422 that link together a number of nodes 424. As will be appreciated by the skilled person, as the number of nodes of a geographical zone increases, so does the complexity of the shape of the geographical zone. In some cases, it may be necessary to define a rather complex geographical zone including a large number of nodes, for example where the visual extent of a landmark varies sharply with position. As the complexity of the shape of a geographical zone increases however, so does the amount of computation required when comparing a monitored geographical position to positions within the node. Simply comparing a monitored geographical position to a large number of positions known to lie within a geographical zone may be unacceptable due to the large amount of data that must be stored. Accordingly, it may be preferable to apply spatial algorithms that describe the zone and the positions that it encompasses by a series of vectors linked together at nodes such as the nodes 424 shown in Figure 11. However, algorithms of this kind may suffer heavily from the problem described above in relation to complex zone shapes. To alleviate this problem, a further geographical zone, referred to herein as a buffer zone, or bounding box, can be employed. One example of a buffer zone is shown in Figure 11. The buffer zone 440 shown in Figure 11 encompasses the geographical zone 420. The buffer zone 440 in this example is quadrangular. Figure 11 also shows a Cartesian frame of reference 430 within which the buffer zone 440, the geographical zone 420 and monitored geographical positions can be represented for the purposes of implementing embodiments of the invention. For ease of calculation, the buffer zone 440 can be aligned so that its sides 442 are parallel with the axes of the Cartesian frame 440, and can thereby be represented by coordinate pairs, for example the X,Y co-ordinates of the bottom left and top right corners. In this example, monitoring the geographical position of a mobile device includes two phases. In the first phase, the monitored geographical position of the mobile device as determined from, for example, GPS log data is used to determine whether the position lies within the buffer zone 440. Since the buffer zone is quadrangular and is aligned with the Cartesian frame, this involves a simple calculation to determine whether the X and Y values of the monitored geographical position lie within the range of X and Y values which correspond to the outer limits of the buffer zone 440 (e.g., of the bottom left and top right corners). For positions that are determined to lie outside the buffer zone 440 (for example at the monitored geographical position 450), there is no need to perform the relatively complex calculations required to determine whether the monitored geographical position lies within the geographical zone 420. A significant number of unnecessary calculations can thereby be avoided. In this example, it is only when it is determined that the monitored geographical position lies within the buffer zone 440 (for example, at monitored position 452) that the calculations comparing the monitored geographical position to the geographical zone 420 begin. In the example shown in Figure 12, a route between a starting point 540 and a destination 542 has been selected using a series of vectors of the ITN layer of the OS MasterMap. These vectors correspond to roads in the road network 550. The starting point 540 and the destination are resolved onto the nearest vectors in the ITN layer, namely vectors 578 and 566 respectively. The selected route starts from the starting point as resolved onto the vector 578 and traverses a portion of the vector 578, the vectors 560, 562 and 564, and a portion of the vector 566. These vectors and connected together at the nodes 520, 522, 524 and 526. The geographical position of the mobile device can be monitored by a GPS device and resolved onto the vectors in the ITN layer as described above in relation to Figure 10.

On the route, three geographical zones 582, 584 and 586 and their associated landmarks 502, 504 and 506 have been selected in accordance with an itinerary for the journey. As described herein, as the user travels from the starting point 540 to the destination 542, the mobile device can display visual representations of the landmarks 502, 504 and 542 when it is determined that the appropriate boundaries of the geographical zones 582, 584 and 586 are crossed. Also, the mobile device can output navigational instructions in conjunction with the visual representations.

In this example, as the user moves along the road which is represented by the vector 560 and towards the cross-roads which is represented by the node 522, he will be provided with a visual representation of the landmark 502 along with instructions which direct him to make a left turn at the cross-roads. Assuming that the user follows these instructions correctly, he will subsequently travel toward the next landmark, namely the landmark 504. At or near to the next cross-roads (when the landmark 504 comes into view, for example), which is represented in the ITN layer by the node 524, the user will be provided with a visual representation of the landmark 504 along with instructions to make another left turn. Again, assuming that these instructions are following correctly by the user, he will travel toward the next landmark 506. At or near to the T-junction represented by the node 526, the user will be provided with a visual representation of the landmark 506 along with instructions to make a right turn. Thus the user is provided with directions from the starting point 540 to the destination 542.

In some examples, provision can be made to enable a user to navigate their way to a destination, even where they have strayed from the initially chosen selected route. An example of this is now described in relation to Figure 12.

Figure 12 shows a number of additional landmarks 508, 510 and 512, and their associated geographical zones 588, 590 and 592. In this example, these landmarks have been selected in case the user strays from the route described above. For example, instead of making a left turn at the crossroads represented by the node 522, the user may erroneously turn right, or he may go straight ahead. In these cases, the user will subsequently pass through a boundary of one of the geographical zones 590 or 588. The mobile device can respond to determination that one of those boundaries has been crossed by outputting navigational instructions to enable the user to return to the correct route. For example, if at the cross-roads represented by the node 522, the user erroneously turns right he will subsequently pass through the boundary of the geographical zone 588 and can be provided with navigational instructions to turn around and head back toward the cross-roads. If the user correctly follows these correctional instructions, he will subsequently re-enter the geographical zone 582 and can be provided with a visual representation of the landmark 502 along with instructions to go straight ahead at the cross-roads. Similarly, at the cross-roads represented by the node 524, the user erroneously makes a right turn instead of a left turn, he will subsequently pass through the boundary of the geographical zone 572 and can be provided with navigational instructions to turn around and head back toward the cross-roads. Visual representations of the negative landmarks can be displayed to enable to the user to confirm to himself that he has indeed taken the wrong route.

In the example described above, there is no requirement for a whole new itinerary to be prepared each time the user strays from the correct route. Instead, the additional landmarks, vectors, visual representations and correctional navigational instructions can be prepared along with the vectors, landmarks, visual representations and navigational instructions of the correct route. Selection of the additional landmarks an so forth can be carried out using a search algorithm which searches along all of the vectors which branch away from each node in the correct route. For example, in Figure 12, the negative landmarks 508 and 510 were selected by searching along the vectors which branch away from the node 522 (namely along the vectors 568 and 570) which a not vectors of the correct route. The search may be limited to propagate only a fixed distance along each vector. For example the search may only propagate as far as the next node as far as a predetermined geographical distance, for example 100 meters. In some examples, more than one visual representation of a landmark can be displayed. In this regard, visual representations can be displayed simultaneously as a group and/or as a series of visual representations (or groups of visual representations) displayed one after the other. Where a plurality of visual representations are shown simultaneously, the group of visual representations may be selected on the basis of a rank calculated according to the factors described above. Where the visual representations are displayed in a series, a determination as to when to switch visual representations can be made following criteria involving the geographical position of the mobile device and/or the direction of travel of the mobile device as described above.

Accordingly, as the user travels past a landmark, he may be shown a number of views of the landmark, which may help the user to identify the landmark and to ensure that any navigational instructions outputted in conjunction with the landmark have been followed correctly.

In some examples, having displayed one or more visual representations of a landmark in response to the user entering a geographical zone, the mobile device can stop displaying those views when it is determined that the mobile device has passed through another boundary of the geographical zone to exit the geographical zone.

In some implementations, geographical zones may be associated with more than one landmark. Indeed, a geographical zone associated with a particular landmark need not actually represent the visual extent of that landmark. An example of this is now described in relation to Figure 13.

Figure 13 shows a portion of the geographical area 100 shown in Figure 4. The portion includes the landmarks 124 and 122. The route 130 is again shown as a dashed line. The geographical zone 128 shown in Figure 13 is associated with the landmark 122 in that it represents the visual extent of the landmark 122. The geographical zone 128 is also associated with the landmark 124. In this example, instead of displaying a visual representation of a first landmark when it is determined that the mobile device has entered a geographical zone, a visual representation of a next landmark is displayed when a previous landmark is determined to be no longer visible. To implement this, a visual representation of the next landmark on a route can be displayed when the mobile device is determined to have passed through a boundary to exit a geographical zone representing the visual extent of a previous landmark. ϊn the example shown in Figure 13, the user is travelling along the route 130 from the starting point 110 to the destination 120 (see Figure 4). By following the route 130, the user passes by the landmark 122 and then passes by the landmark 124. As the mobile device carried by the user exits the geographical zone 128 which represents the visual extent of the landmark 122 (this will occur at or near to the point 129), a visual representation of the next landmark on the route, namely the landmark 124, is retrieved and displayed. This prompts the user to begin looking for the landmark 124.

Although not illustrated in Figure 13, the landmark 124 may also have a geographical zone associated therewith. As the mobile device enters that geographical zone, display of the visual representation may be maintained or ceased, and/or other further visual representations may be displayed. Additionally, in response to entering that geographical zone, the mobile device may output navigational instructions to be followed at the landmark 124 as described above. Subsequently, as the user travels past the landmark 124, it can be determined that the mobile device has exited the geographical zone representing the landmark 124 and a visual representation of a next landmark can be retrieved and displayed. By navigating to a series of next landmarks, the user can successfully navigate from the starting point 110 to the destination 120. Another example in which more than one geographical zone is associated with a landmark is shown in Figure 14. Figure 14 shows the building 124 and three geographical zones associated therewith. Where multiple zones are used in this way, each zone may serve a particular purpose. In this example, the geographical zone 600 corresponds to the visual extent of the building 124 in the area immediately surrounding the building. The geographical zone 602 generally surrounds the geographical zone 600 and is associated with the visual extent of the building 124 from positions somewhat further away from the building 124. Similarly, the geographical zone 604 is associated with the visual extent of the building 124 from positions still further away from the building 124. Nesting the geographical zones in this way, allows different visual representations of the building to be displayed when the user is a various distances therefrom, each view being appropriate to the actual distance of the user from the building.

Figure 15 shows an example of the display output on the display 610 of a mobile device, for implementing the invention. The display output can include a map portion 612. In this example, the map portion represents a portion of the geographical area 100 shown in Figure 4. The map can include features such as a representation 640 of the landmark 124 and a representation 620 of the destination 120. A representation 630 of the route 130 can also be included, as can a representation 660 of the monitored geographical position of the mobile device. A representation 650 of a geographical zone such as the geographical zone 180 can also be shown. Alternatively, the geographical zone 180 may not be displayed. The map can be user-scrollable. In some implementations, the representation 660 of the monitored geographical position of the mobile device can be fixed relative to the display 610 and the map portion 610 can move relative to the representation 660 as the geographical position of the mobile device changes.

A display area 670 can be used to display one or more visual representations of a landmark as described in the examples given above. Similarly, a display area 680 can be used to output textual information such as navigational instructions and/or information regarding the landmarks as described above. Other areas of the display 610 can be reserved for other display objects such as icons, scroll bars and the like.

In some examples, a visual representation may be formed of or derived from a digital photograph of a landmark. A "digital photograph" can be any photograph recorded in a digital or digitised format. Alternatively, the visual representation may be a graphical representation.

In other examples, a three-dimensional visual representation of the landmark may be provided for display. One or more digital photographs, video sequences or graphical representations may be used to provide such a three-dimensional visual representation. An example of this is illustrated in Figures 16a and 16b.

More generally, the term visual representation of a landmark as used herein can be in the form of one or more images or other displayed representations formed by or is derived from one or more photographs, whether they be digital photographs or digitised photographs, graphical representations, video sequences, etc. The actual image(s) or other displayed representation(s) of the landmark forming the visual representation be derived from one or more photographs in that the photograph(s) may be subjected to scaling, rotation and/or other image manipulations to provide an appropriate view of the landmark.

For example, Figure 16A shows an example of a three-dimensional model 700 for displaying a visual representation of a landmark. The model 700 includes a frame 730 which can be formed from a number of vectors connecting together a series of nodes 732. The dimensions of the frame can be chosen to match the proportions of the landmark. The model in this example also includes two digital photographs 710, 720 of the landmark are mapped to the frame. In this example the landmark is a house. The photograph 710 shows a front view of the house while the photograph 720 shows a side view. The three-dimensional model 700, including the two-dimensional photographs 710, 720, can be rendered from any particular angle as a two-dimensional visual representation for display on a mobile device. This allows the use of one or more photographs to provide an effective visual representation of a landmark from any particular direction.

The orientation of the model 700 in a visual representation can, for example, be varied according to the users monitored geographic position relative to the landmark. The user may also be able to select a view of the landmark from a particular angle. For example, Figure 16B shows another view of the model 700, following a rotation of the model 700 as shown in Figure 16A in the direction indicated by the arrow labelled 'G'. After the rotation, the photograph 710 cannot be seen, whereas the photograph 720 has been brought to the fore.

A user can effect rotation of the model in this way by using, for example, a user input such as cursor keys or by dragging a stylus across a touch sensitive display on which the visual representation is displayed.

The three-dimensional visual representations as described herein can, for example, be implemented using the VRML (Virtual Reality Modeling Language) file format. Information regarding the VRML file format and VRML specifications can be found at http://www.web3d.Org/x3d/specifications/vrml/NRMLl.0/index.html and at http://www.web3d.org/x3d/specifications/vrml/index.html. Information regarding suitable modeling software can be found at http://wwwphoto3d.com/eindex.html. More details concerning example embodiments of the invention will be described in more detail hereinafter. In particular, methods for preparing an itinerary for a journey between a geographical starting point and a geographical destination will now be described in relation to Figures 17 to 19. Figure 17 provides an overview of a method for preparing an itinerary using an example of a mobile client device, such as the mobile device 28 shown in Figure 2, in which data 39 such as map data, information regarding landmarks and geographical zones associated therewith are stored locally at the mobile device, for example in the memory 40.

The landmark data can be stored as files or objects containing data defining a visual representation of the landmark, along with data identifying characteristics of the landmark and the geographical position of the landmark, and the associated geographical zone or zones. Program code 41 forming one or more computer program products can also be held in the memory 40 of the mobile device 28 for causing the processor 36 to perform processing steps to be described in the following. At step 800, the program code can be operable to respond to the user of the mobile device 28 entering a destination, for example using the keypad 32 or a touchscreen display 30 of the mobile device 28 to identify the destination. The user may enter a destination in different ways, for example by entering a place-name, address and/or postcode of the destination into the mobile device 28. Alternatively, the user may be able point to the destination on a map displayed on the mobile device. The program code is operable to store information defining the destination, for example in the form of map coordinates. Where vectors connected at nodes (such as ITN vectors and nodes) are used for selecting a route, the destination may be a node in the network. Alternatively, the mobile device program code can be operable to resolve the destination to a position along a nearest vector or onto the nearest node.

At step 802, a starting point is selected. For example, the program code can be operable to respond to the user of the mobile device 28 entering a starting point into the mobile device, for example in the manner in which the destination at selected in step 800. In some examples, the program code may be operable to define default starting point as a present geographical position of the mobile device as identified by position signals from the positioning device 44, (for example a global positioning device) of the mobile device. Where vectors connected at nodes (such as ITN vectors and nodes) are used for selecting a route, the starting point may be a node in the network. Alternatively, the mobile device program code can be operable to resolve the starting point to a position along a nearest vector or onto the nearest node.

It will be appreciated that the order of selecting the starting point and destination may be reversed. At step 804, the program code of the mobile device can be operable to use the information determined in steps 800 and 802 to prepare an itinerary for the journey from the starting point to the destination. The itinerary can include a route and at least one geographical zone.

The program code can be operable to use the methodology described earlier, using algorithms that take into account factors such as shortest distance, anticipated journey times and/or availability of suitable landmarks, to generate the route. In some implementations, the route may be selected in accordance with further information entered be the user.

For example, the route may include one or more waypoints selected by the user. Indeed, the route may be entirely defined by the waypoints, the starting point and the destination. Waypoints can allow a user to ensure that they pass by certain landmarks or geographical positions while traversing the route. A waypoint may, for example, be the geographical position of a particular landmark. This would allow a route to be chosen on the basis of landmarks to be visited, for example, where a tourist wishes to visit a series of landmarks. The program code can also be operable to take into account a mode of travel of the user as a factor in route selection. For example, a user travelling by foot would not be constrained to travelling by road, as would a user travelling in a motor vehicle. Similarly, route selection may take into account factors such as one-way streets (these would not need to be accounted for where the user is travelling by foot, for example), height clearances (of low bridges, for example), the presence of cycle lanes and so forth. The program code can also be operable to take into account an age of the user as a factor in route selection. For example, some geographical areas may be designated as unsuitable or indeed unsafe for travel for user of certain ages. The time of travel (eg evening) may also be a factor in this regard. The route can be selected to avoid such areas as appropriate. The mobility of a user may also be a factor in route selection. For example, a route may be selected with wheel chair access as a criterion. Information regarding these factors may be inputted by the user where necessary, and used to select the route. The route may also be selected according to temporal factors such as such as the time of day (eg rush hour), and the time of year (at certain times of year, seasonal weather conditions may make one route preferable over another).

The route may be selected in accordance with data stored in a database such as Ordnance Survey's MasterMap as described above. Accordingly, the route may include a series of vectors connected at nodes, such as vectors and nodes of the ITN layer. Once a route has been determined, the program code can be operable to identify one or more geographical zones associated with landmarks. Data describing a number of landmarks in the area and geographical zones associated therewith can be stored on the mobile device. This data can be used to select landmarks/geographical zones appropriate for the selected route. In some implementations, the geographical zone or zones may be calculated at this stage. Alternatively, the geographical zone or zones may have been predefined earlier and stored in memory for selection once an appropriate route has been determined.

The program code can be operable to select a number and/or type of landmarks/geographical zones according to a number of factors.

One such factor is the mode of transport of the user. As user travelling in motor vehicle is unlikely to require as many landmarks as a user travelling by foot. In particular, a person driving a car does should not be distracted by a continuous flow of information relating to successive, closely spaced landmarks. Conversely, a user travelling by foot does not need to concentrate upon driving and can give the mobile device more attention. Also, some landmarks may be difficult to spot for a user travelling in a motor vehicle and these types of landmarks can be omitted from the itinerary where appropriate. The user may also select a type of landmark by which to navigate. For example, categories could include historic buildings, public houses, train stations and so forth. The program code can then be responsive to this user selection to identify appropriate landmarks based on type information stored with the landmark information in the memory 40.

The landmarks/geographical zones may also be selected according to temporal factors such as such as the time of day (eg opening hours of a museum or gallery), and the time of year (for example, some tourist attractions may not be available all year round).

The program code can also be operable to associate boundaries of the geographical zones with visual representations (as described in relation to Figure 9), which it is anticipated will be required as the user traverses the route.

The program code can also be operable to select additional landmarks/geographical zones such as negative landmarks in anticipation that the user may stray from the correct route. For example, the itinerary may include the additional vectors and nodes as well as the additional geographical zones, visual representation and navigational instructions as described in relation to Figure 12 above.

The selection of such geographical zones and the associated landmarks, in the absence of specific identification thereof by the use can be performed by the program code tracing the route that has been determined and identifying geographical zones that lie along that route. This can be achieved using the positional information associated with the geographical zones/landmarks. As indicated above, where the route is selected taking into account selected landmark types, then those landmarks can form way points along the route and can be used by the program code to determine the route. The program code can also be operable to associate available audible and/or textual information such as navigational instructions and/or information regarding the landmarks for output in conjunction with the visual representations. The navigational instructions can be selected in accordance with the selected route and can include instructions such as "turn left", "straight on" and so forth. Data describing the itinerary including the route and the geographical zones/landmarks can be stored in the memory of the mobile device for immediate or later use.

The program code and/or the data held in the memory 40 can be kept up to date, for example by connecting the mobile device to a server for downloading of the latest information.

Figure 18 provides an overview of an example of a method of operating a client device where the generation of an itinerary is performed using real time communication with a server. Providing for at least some of the functionality described with reference to Figure 17 being performed at a high performance server in communication with a mobile client device means that the mobile client device can be kept simpler and/or more complex mapping can be accommodated. At steps 810 and 820 a destination and a starting point are determined as described above with reference to steps 800 and 802 in Figure 17.

At step 814, however, data describing the destination and the starting point are transmitted to the server. As described below, the server can use the data describing the destination and the starting point to prepare an itinerary. Preparation of an itinerary may require a large amount of computing resources, especially in terms of storage space for storing map data and data regarding landmarks and associated geographical zones. Preparing the itinerary at a server negates the need for substantial computing resources to be made available at a mobile client device. The data can be transmitted to the server as one or more packets of information via, for example, a mobile telephony network. Data describing the itinerary prepared at the server can then be received, for example via the mobile telephony network and in the form of one or more packets of data, at the mobile client device at step 816. The data that is received can include, for example, the underlying mapping data and, overlaid thereon, the selected route, along with data defining the geographical zones, the visual representations, and any other associated information, such as, for example audio information to be supplied to the user. This mapping data can be provided, for example, in the form of raster scanned mapping data, or vector-based mapping data. Figure 19 provides an overview of an example of the operation of a server that can be used in conjunction with the operation of a mobile client device as described in Figure 18. The server can be a computer server such as has been described with reference to Figure 3 in which appropriate data is stored in the memory 52 and/or storage 54, and suitable program code forming one or more computer programs is stored in the memory 52 and/or the storage 54 for controlling the processor 50. At step 820, the server program code can be operable to receive from the mobile client device the data describing a destination and a starting point. At step 822, the server program code can be operable to use the data received from the mobile client device to prepare an itinerary. The server program code can be operable to prepare the itinerary using a methodology such as has been described in relation to step 804 of Figure 10. In step 824 the server program code can then be operable to transmit to the mobile client device data describing the itinerary. The server can also store data describing the itinerary locally.

Figure 20 provides an overview of a method performable by a mobile device for allowing a user to navigate from a starting point to a destination. In this example, the mobile device does not communicate with a server. It should be noted however, that prior to the performance of the method shown in Figure 20, any of the methods described in relation to Figures 17 to 19 may have been performed for preparing an itinerary. While the preparing of an itinerary and the method performed during actual navigation may both be performed at a mobile device, in some implementations the itinerary preparation and/or navigation methods may be performed using server client communications.

At step 830, as a user is travelling from, for example, a starting point to a destination, the mobile device monitors the geographical position of the mobile device using a positioning device such as a global positioning device. As described above, the geographical position may be represented in a Cartesian or other co-ordinate system. Other features such as roads, roundabouts, rivers and so forth may also be represented in the co-ordinate system. Additionally, one or more geographical zones as described above may be represented in the co-ordinate system as a two-dimensional polygon made up of nodes connected by vectors forming boundaries. A route to be taken can be represented as a series of vectors (for example, ITN vectors). By comparing the geographical position of the mobile device with the geographical zones as represented in the coordinate system, the mobile device code can be operable to determine when it has passed through a boundary of a geographical zone.

At step 832, where no boundary of a geographical zone has been passed through by the mobile device, control loops back to step 830 and the monitoring of the geographical position of the mobile device continues. If however at step 832 it is determined that the mobile device has passed through a boundary of a geographical zone, control passes to step 834.

At step 834, the mobile device accesses and displays a visual representation of a landmark with which the geographical zone (whose boundary has been passed through) is associated. Where there is more than one visual representation of the landmark available, the mobile device can use the methods described above to select one or more visual representations. As described above, in some examples, the geographical zone is representative of the visual extent of the landmark, whereas in other examples the geographical zone may be associated with the landmark insofar as the landmark is a next landmark on a route. In each case, the mobile device retrieves the visual representation of the landmark that can be stored in, for example, a memory of the mobile device. The mobile device can also output textual and/or audible navigation information regarding the landmark.

In conjunction with the method described in relation to Figure 20, the mobile device can display a map such as a map showing a representation of the local area and a route to be taken. The mobile device can also display a representation of the monitored geographical position on the map. These display features can further aid the user in navigating. Subsequent to the display of the visual representation, the mobile device can, for example access and display one or more further visual representations of the landmark as described above.

Subsequent to the described method, the mobile device can return to step 830 and begin the described method for a next geographical zone on a selected route. By performing one or more iterations of the method described in relation to Figure 20, the mobile device can allow the user to navigate from a starting point to a destination.

The method described with reference to Figure 20 can be performed by program code held in the memory 40 of the mobile device 28. Figure 21 provides an overview of a method performable by a mobile client device for allowing a user to navigate from a starting point to a destination. At step 840, as a user is travelling from, for example, a starting point to a destination, the mobile client device monitors the geographical position of the mobile client device using a positioning device such as a global positioning device. As described in relation to step 830 of Figure 20, the monitored geographical position and one or more geographical zones as well as features such as roads can be represented in a Cartesian or other coordinate system. For example, the geographical zone may be represented as a two- dimensional polygon made up of nodes connected by vectors forming boundaries. A route to be taken can be represented as a series of vectors. By comparing the geographical position of the mobile client device with the geographical zones as represented in the co-ordinate system, it is possible to determine when the mobile client device has passed through a boundary of a geographical zone.

Analogously to the method described in relation Figure 20, at step 842, where no boundary of a geographical zone has been passed through by the mobile client device, control loops back to step 840 and the monitoring of the geographical position of the mobile client device continues. If however at step 842 it is determined that the mobile client device has passed through a boundary of a geographical zone, the control passes to step 844.

At step 844, the mobile client device program code accesses a visual representation for display. In this example, the accessing includes sending a request for a visual representation of the landmark with which the geographical zone whose boundary has been passed through is associated. Where there is more than one visual representation of the landmark available, the mobile client device can use the methods described above to select one or more visual representations. In some implementations, the server may select which visual representation or visual representations are to be displayed. At step 846, the mobile client device receives from the server a visual representation of the landmark and displays the visual representation on its display. The mobile client device can also output textual and/or audible navigation information regarding the landmark.

In conjunction with the method described in relation to Figure 21, to further aid navigation of the user the client mobile device can display a map such as a map showing a representation of the local area and a route to be taken. The mobile client device can also display a representation of the monitored geographical position on the map. A representation of one or more geographical zones can also be displayed on the map. In some examples, the mobile client device can receive data from the server describing the map and use that data to reproduce and display the map. The map can be updated where necessary using data received from the server. Subsequent to the display of the visual representation, the mobile client device can, for example access and display one or more further visual representations of the landmark as described above.

Subsequent to the described method, control can pass back to step 840 and begin the described method for a next geographical zone on a selected route. By performing one or more iterations of the method described in relation to Figure 21, the mobile client device can allow the user to navigate from a starting point to a destination.

In some implementations using a mobile client device and server arrangement, the mobile client device can monitor the position of the mobile client device and send positioning data describing the monitored position to a server. The server can receive the positioning data and use it to determine whether the mobile client device has passed through a boundary of a geographical zone. This determination can be made by the server using the co-ordinate system representation of the geographical position and the geographical zones described above in relation to Figure 20 and 21. In such implementations, the server is in a position to notify the mobile client device that it has crossed a boundary of a geographical zone and to send it an appropriate visual representation for display with the need for an explicit request from the mobile client device. Where there is more than one visual representation of the landmark available, the server can use the methods described above to select one or more visual representations to send to the mobile client device.

In some implementations using a mobile client device and server arrangement, the mobile client device may pre-request visual representations of landmarks. For example, the mobile client device may pre-request and store in memory some or all of the visual representations that it is anticipated that it will require in conjunction with a prepared itinerary. The mobile client device can then access and display pre-requested visual representations stored in its memory as required. This can reduce access times when a given visual representation is required for display. Figure 22 provides flow diagram illustrating an example of operation of a mobile device. In this example, map data and itinerary data, including data defining relevant geographical zones (which data can include an edge table as illustrated in Table 1 above for each of those geographical zones) are held in the memory of the mobile device, typically after having been downloaded from a server. The visual representations are, however, held at a server and are downloaded in real time as required. The steps shown in Figure 22 are described with reference to Figure 7. In Figure 22, steps illustrated to the left of the dashed line are performed at the mobile device, and steps to the right of the dashed line are performed at a server.

Step 902 represents the generation of co-ordinate data at respective times by a positioning device (e.g,, a GPS device). The co-ordinate data correspond to the mobile device positions represented by points 1, 2, 3, 4, 5, 6, 7 and 8 in Figure 7. In step 904, on the generation of each set of co-ordinates, a mobile device program is operable to determine whether a trip zone has been activated, that is whether the mobile device has moved from outside to inside the geographical zone. This is achieved as described above with reference to Figure 8, by computing the first time that the current co-ordinates lie within a polygon corresponding to the geographical zone. As illustrated in Figure 7, this occurs for point 8, whereby point 7 is outside the zone and point 8 is within the zone.

At step 906, when it is determined that the mobile device has moved into a trip zone, then the mobile device computer program is operable to interpolate along a line joining the most recent point and the previous point (in the illustrated example, points 8 and 7, respectively.

In step 908 the mobile device computer program is operable to compute an edge intersection point 9 between that line and the appropriate edge (here edge El) of the polygon PI. In step 910, the mobile device computer program can be operable to access an edge table as shown in Table 1 above to identify a visual representation to be displayed in the event that the edge El is crossed, and to query, at 912 the server to obtain the appropriate visual representation for display.

In step 914, the server is operable to query a landmarks database for the visual representation concerned (here visual representation L1.N1). The visual representation is retrieved in step 916 and is sent to the mobile device at 918. The visual representation is then displayed at step 920 by the mobile device, for example in a window on the display of the mobile device. The visual representation can be maintained until the user closes the window, or it can be automatically removed, for example when the mobile device determines that it has crossed another edge of the polygon leaving the geographical zone PI.

In the above example, the visual representations are downloaded on demand. However, at least some of the visual representations associated with a given route could instead be downloaded in advance to provide greater responsiveness. For example, the visual representations associated with adjacent geographical landmark zones to a current position could automatically be downloaded from the server to the mobile client device in advance of them being needed to improve responsiveness. Indeed, in response to determination of a given route, all the of the potentially required visual representations could be downloaded to the mobile client device along with the mapping and other data subject to sufficient memory capacity being available at the client device.

Aspects of the invention are set out in the following series of numbered clauses.

1. A mobile client device comprising a processor, memory, a display, a positioning device, a user input and a transmitter and a receiver for communicating with a server via a communications network, the mobile client device being operable to: monitor a geographical position of the mobile client device using the positioning device; and respond to a determination that the mobile client device has passed through a boundary of a geographical zone associated with a landmark by: - accessing a visual representation of the landmark; and displaying the visual representation on the display.

2. The mobile client device of clause 1, operable to: receive data describing a geographical destination via the user input; - transmit the data describing the geographical destination to the server; and transmit data describing a geographical starting point to the server.

3. The mobile client device of clause 2, wherein the geographical starting point is a geographical position of the mobile client device determined by the positioning device.

4. The mobile client device of clause 2 or clause 3, operable to receive data describing an itinerary from the server, the itinerary including: a route from the geographical starting point to the destination; and - the geographical zone.

5. The mobile client device of clause 4, operable to receive data describing one or more user defined waypoints via the user input and to transmit the data describing the waypoints to the server, wherein the route includes the waypoints.

The mobile client device of any preceding clause, operable to display: a map; and a representation of the monitored geographical position of the mobile client device on the map. 7. The mobile client device of clause 6, operable to receive data corresponding to the map from the server, and to update the map on the display using the data from the server.

8. The mobile client device of clause 6 or clause 7, operable to display a representation of the geographical zone on the map.

9. The mobile client device of any preceding clause, operable to respond to the determination that the mobile client device has passed through the boundary of the geographical zone by: sending a request for a visual representation of the landmark to the server; receiving a visual representation of the landmark from the server; and displaying the visual representation of the landmark on the display.

10. The mobile client device of any preceding clause, operable to send a pre-request for a visual representation of a landmark to the server; receive a pre-requested visual representation of a landmark from the server; and store the pre-requested visual representation in the memory.

11. The mobile client device of any preceding clause, operable to display the visual representation of the landmark in response to a determination that the mobile client device has entered the geographical zone.

12. The mobile client device of any of clauses 4 to 11, operable to display the visual representation of the landmark in response to a determination that the mobile client device has exited the geographical zone, the landmark being a next landmark on the route. 13. The mobile client device of any preceding clause, wherein the visual representation is selected according to the monitored geographical position of the mobile client device.

14. The mobile client device of clause 13, wherein the visual representation is selected according to a tracking vector based upon a plurality of monitored geographical positions of the mobile client device.

15. The mobile client device of any preceding clause, wherein the visual representation is selected according to which boundary of the geographical zone the mobile client device is determined to have passed through.

16. The mobile client device of any preceding clause, operable to display one or more further visual representations of the landmark on the display in response to user input.

17. The mobile client device of clause 4 or any clause dependent thereon, wherein the itinerary includes a further geographical zone associated with the landmark.

18. The mobile client device of clause 17, operable to: respond to a determination that the mobile client device has passed through a boundary of the further geographical zone associated with the landmark by: accessing a visual representation of the landmark; and - displaying the visual representation on the display.

19. The mobile client device of clause 17, wherein the further geographical zone associated with the landmark is a buffer zone which encompasses the geographical zone, and wherein the mobile client device is operable to: respond to a determination that the mobile client device is positioned within the buffer zone by monitoring the geographical position of the mobile client device with respect to the geographical zone; and respond to a determination that the mobile client device is not positioned within the buffer zone by not monitoring the geographical position of the mobile client device with respect to the geographical zone.

20. The mobile client device of clause 4 or any clause dependent thereon, wherein the itinerary includes a further geographical zone associated with a further landmark.

21. The mobile client device of clause 20, operable to respond to a determination that the mobile client device has passed through a boundary of the further geographical zone associated with the further landmark by: accessing a visual representation of the further landmark; and - displaying the visual representation of the further landmark on the display.

22. The mobile client device of clause 20 or clause 21, wherein the route does not pass through the further geographical zone associated with the further landmark, the mobile client device being operable to respond to a determination that the mobile client device has passed through a boundary of the further geographical zone associated with the further landmark by outputting navigational instructions for navigating back to route.

23. The mobile client device of clause 4 or any clause dependent thereon, wherein the determination that the mobile client device has passed through a boundary of a geographical zone associated with a landmark is^' made by comparing the monitored geographical position of the mobile client device with geographical positions within the geographical zone.

24. The mobile client device of clause 4 or any clause dependent thereon, wherein the route is represented by a series of vectors. 25. The mobile client device of clause 24, wherein the determination that the mobile client device has passed through a boundary of the geographical zone associated with the landmark is made by resolving the monitored geographical position of

5 the mobile client device onto a vector representing the route, and by comparing the resolved geographical position of the mobile client device with positions on the vector which coincide with positions within the geographical zone.

26. The mobile client device of any preceding clause, wherein each geographical zone o is represented by a polygon in two or more dimensions.

27. The mobile client device of any preceding clause, operable output at least one of textual and audible navigation information regarding the itinerary to the user. 5 28. The mobile client device of any preceding clause, wherein the positioning device is a global positioning device.

29. The mobile client device of any preceding clause, operable to transmit data describing the geographical position of the mobile client device to the server.0 30. A server operable to: receive from a mobile client device data describing: a geographical destination; and a geographical starting point,5 - use the data received from the mobile client device to prepare an itinerary for the mobile client device, the itinerary including: a route from the starting point to the destination; and a geographical zone associated with a landmark, transmit data describing the itinerary to the mobile client device; and respond to a determination that the mobile client device has passed through a boundary of a geographical zone by transmitting a visual representation of the landmark to the mobile client device.

31. The server of clause 30, operable to: receive positioning data from the mobile client device describing a geographical position of the mobile client device; monitor the geographical position of the mobile client device using the positioning data; and - determine whether the mobile client device has passed through a boundary of the geographical zone.

32. The server of clause 30, operable to receive a request from the mobile client device for a visual representation of the landmark, and to respond by transmitting a visual representation of the landmark to the mobile client device.

33. The server of any of clauses 30 to 32, wherein the visual representation is selected according to the monitored geographical position of the mobile client device.

34. The server of clause 33, wherein the visual representation is selected according to a tracking vector based upon a plurality of monitored geographical positions of the mobile client device.

35. The server of clause 33, wherein the visual representation is selected according to which boundary of the geographical zone the mobile client device is determined to have passed through.

36. The server of any of clauses 30 to 35, wherein the itinerary includes a further geographical zone associated with the landmark. 37. The server of clause 36, operable to respond to a determination that the mobile client device has passed through a boundary of the further geographical zone associated with the landmark by transmitting a visual representation of the landmark to the mobile client device.

38. The server of any of clauses 30 to 37, wherein the itinerary includes a further geographical zone associated with a further landmark.

39. The server of clause 38, operable to respond to a determination that the mobile client device has passed through a boundary of the further geographical zone associated with the further landmark by transmitting a visual representation of the further landmark to the mobile client device.

40. The server of any of clauses 30 to 39, wherein the determination that the mobile client device has passed through a boundary of a geographical zone associated with a landmark is made by comparing the monitored geographical position of the mobile client device with geographical positions within the geographical zone.

41. The server of any of clauses 30 to 40, wherein the route is represented by a series of vectors.

42. The server of clause 41, wherein the determination that the mobile client device has passed through a boundary of the geographical zone associated with the landmark is made by resolving the monitored geographical position of the mobile client device onto a vector representing the route, and by comparing the resolved geographical position of the mobile client device with positions on the vector which coincide with positions within the geographical zone.

43. The server of any of clauses 30 to 42, wherein each geographical zone is represented by a polygon in two or more dimensions. 44. The server of any of clauses 30 to 43, operable to transmit at least one of textual and audible information regarding the itinerary to the mobile client device.

45. The server of any of clauses 30 to 44, operable to receive from the mobile client device data describing one or more user defined waypoints and to include the waypoints in the route when preparing the itinerary.

46. The server of any of clauses 30 to 45, operable to transmit to the mobile client device data corresponding to a portion of a map requested by the mobile client device.

47. A mobile device comprising a processor, memory, a display, a positioning device and a user input, the mobile device being operable to: monitor a geographical position of the mobile device using the positioning device; and respond to a determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark by: accessing a visual representation of the landmark; and displaying the visual representation on the display.

48. The mobile device of clause 47, operable to: receive data describing a geographical destination via the user input; determine a geographical starting point; and prepare an itinerary including: - a route from the starting point to the destination; and the geographical zone.

49. The mobile device of clause 48, wherein the geographical starting point is a geographical position of the mobile device determined by the positioning device. 50. The mobile device of clause 48 or clause 49, operable to receive data describing one or more user defined waypoints via the user input and to include the waypoints in the route when preparing the itinerary.

51. The mobile device of any of clauses 47 to 50, operable to display: a map; and a representation of the monitored geographical position of the mobile device on the map.

52. The mobile device of clause 51, operable to display a representation of the geographical zone on the map.

53. The mobile device of any of clauses 47 to 52, operable to display the visual representation of the landmark in response to a determination that the mobile device has entered the geographical zone.

54. The mobile device of any of clauses 47 to 52, operable to display the visual representation of the landmark in response to a determination that the mobile device has exited the geographical zone, the landmark being a next landmark on the route.

55. The mobile device of any of clauses 47 to 54, operable to select the visual representation according to the monitored geographical position of the mobile device.

56. The mobile device of clause 55, operable to select the visual representation according to a tracking vector based upon a plurality of monitored geographical positions of the mobile device. 57. The mobile device of any of clauses 47 to 56, wherein the visual representation is selected according to which boundary of the geographical zone the mobile device is determined to have passed through.

58. The mobile device of any of clauses 47 to 57, operable to display one or more further visual representations of the landmark on the display in response to user input.

59. The mobile device of clause 48 or any clause dependent thereon, wherein the itinerary includes a further geographical zone associated with the landmark.

60. The mobile device of clause 59, operable to: respond to a determination that the mobile device has passed through a boundary of the further geographical zone associated with the landmark by: - accessing a visual representation of the landmark; and displaying the visual representation on the display.

61. The mobile device of clause 59, wherein the further geographical zone associated with the landmark is a buffer zone which encompasses the geographical zone, and wherein the mobile device is operable to: respond to a determination that the mobile device is positioned within the buffer zone by monitoring the geographical position of the mobile device with respect to the geographical zone; and respond to a determination that the mobile device is not positioned within the buffer zone by not monitoring the geographical position of the mobile device with respect to the geographical zone.

62. The mobile device of clause 48 or any clause dependent thereon, wherein the itinerary includes a further geographical zone associated with a further landmark. 63. The mobile device of clause 62, operable to respond to a determination that the mobile device has passed through a boundary of the further geographical zone associated with the further landmark by: accessing a visual representation of the further landmark; and - displaying the visual representation of the further landmark on the display.

64. The mobile device of clause 62 or clause 63, wherein the route does not pass through the further geographical zone associated with the further landmark, the mobile device being operable to respond to a determination that the mobile device has passed through a boundary of the further geographical zone associated with the further landmark by outputting navigational instructions for navigating back to route.

65. The mobile device of clause 48 or any clause dependent thereon, wherein the determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark is made by comparing the monitored geographical position of the mobile device with geographical positions within the geographical zone.

66. The mobile device of clause 48 or any clause dependent thereon, wherein the route is represented by a series of vectors.

67. The mobile device of clause 66, wherein the determination that the mobile device has passed through a boundary of the geographical zone associated with the landmark is made by resolving the monitored geographical position of the mobile device onto a vector representing the route, and by comparing the resolved geographical position of the mobile device with positions on the vector which coincide with positions within the geographical zone.

68. The mobile device of any of clauses 47 to 67, wherein each geographical zone is represented by a polygon in two or more dimensions. 69. The mobile device of any of clauses 47 to 68, operable output at least one of textual and audible navigation information regarding the itinerary to the user.

70. The mobile device of any of clauses 47 to 69, wherein the positioning device is a global positioning device.

71. A system comprising a server and a mobile client device, the mobile client device comprises a processor, memory, a display, a positioning device, a user input, and a transmitter and a receiver for communicating with the server via a communications network, the mobile client device is operable to monitor a geographical position of the mobile client device using the positioning device and respond to a determination that the mobile client device has passed through a boundary of a geographical zone associated with a landmark by transmitting to the server a request for a visual representation of the landmark, the server is operable to receive the request and respond by transmitting a visual representation of the landmark to the mobile client device, the mobile client device is operable to receive the visual representation and display the visual representation on the display.

72. A method of providing navigational information on a mobile client device, the method comprising: monitoring a geographical position of the mobile client device using a positioning device of the mobile client device; - the mobile client device responding to a determination that the mobile client device has passed through a boundary of a geographical zone associated with a landmark by transmitting to a server via a communications network a request for a visual representation of the landmark; the mobile client device receiving a visual representation of the landmark; and the mobile client device displaying the visual representation on a display of the mobile client device.

73. A computer program product executable on a mobile client device to cause the mobile client device to become operable to perform the method of clause 52.

74. A method of providing navigational information on a mobile device, the method comprising: monitoring a geographical position of the mobile device using a positioning device of the mobile device; and the mobile device responding to a determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark by: accessing a visual representation of the landmark; and - displaying the visual representation on a display of the mobile device.

75. A computer program product executable on a mobile device to cause the mobile device to become operable to perform the method of clause 74.

76. A method of providing navigational data to a mobile client device, the method comprising a server: receiving from a mobile client device data describing: a geographical destination; and - a geographical starting point, using the data received from the mobile client device to prepare an itinerary for the mobile client device, the itinerary including: a route from the starting point to the destination; and a geographical zone associated with a landmark, - transmitting data describing the itinerary to the mobile client device; and responding to a determination that the mobile client device has passed through a boundary of a geographical zone by transmitting a visual representation of the landmark to the mobile client device.

77. A computer program product executable on a server to cause the server to become operable to perform the method of clause 76.

Although the embodiments above have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated.

For example as described above, embodiments of the invention can be implemented using appropriate software running on computing hardware in a mobile device and on a server. Such software can be provided as one or more computer program products. A computer program product could be in the form of 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 indeed any other transmission medium. In other embodiments of the invention, some or all of the functionality described could, however, also be performed by special purpose hardware and/or firmware using, for example, special purpose, configurable or programmable integrated circuits.

Claims

1. A mobile device comprising a processor, memory, a display, a positioning device and a user input, the mobile device being operable to: - monitor a geographical position of the mobile device using the positioning device; and respond to a determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark by: accessing a visual representation of the landmark; and - displaying the visual representation on the display.

2. The mobile device of claim 1, operable to: receive data describing a geographical destination via the user input; determine a geographical starting point; and - prepare an itinerary including: a route from the starting point to the destination; and the geographical zone.

3. The mobile device of claim 2, wherein the itinerary includes a further geographical zone associated with the landmark, and wherein the mobile device is operable to: respond to a determination that the mobile device has passed through a boundary of the further geographical zone associated with the landmark by: accessing a visual representation of the landmark; and - displaying the visual representation on the display.

4. The mobile device of claim 2, wherein the itinerary includes a buffer zone which encompasses the geographical zone, and wherein the mobile device is operable to: respond to a determination that the mobile device is positioned within the buffer zone by monitoring the geographical position of the mobile device with respect to the geographical zone; and respond to a determination that the mobile device is not positioned within the buffer zone by not monitoring the geographical position of the mobile device with respect to the geographical zone.

5. The mobile device of any preceding claim, operable to select the visual representation according to the monitored geographical position of the mobile device.

6. The mobile device of claim 5, operable to select the visual representation according to a tracking vector based upon a plurality of monitored geographical positions of the mobile device.

7. The mobile device of any preceding claim, wherein the visual representation is selected according to which boundary of the geographical zone the mobile device is determined to have passed through.

8. The mobile device of any of claims 2 to 7, wherein the determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark is made by comparing the monitored geographical position of the mobile device with geographical positions within the geographical zone.

9. The mobile device of any of claims 2 to 8, wherein the route is represented by a series of vectors.

10. The mobile device of claim 9, wherein the determination that the mobile device has passed through a boundary of the geographical zone associated with the landmark is made by resolving the monitored geographical position of the mobile device onto a vector representing the route, and by comparing the resolved geographical position of the mobile device with positions on the vector which coincide with positions within the geographical zone.

11. The mobile device of any preceding claim, wherein each geographical zone is represented by a polygon in two or more dimensions.

12. The mobile device of any preceding claim, operable output at least one of textual and audible navigation information regarding the itinerary to the user.

13. The mobile device of any preceding claim, wherein the device is a mobile client device comprising a transmitter and a receiver for communicating with a server via a communications network.

14. The mobile device of claim 13 when dependent on claim 2, wherein preparing the itinerary comprises: transmitting data describing the geographical starting point and the geographical destination to the server; and receive data describing the itinerary from the server.

15. The mobile client device of claim 13 or claim 14, operable to access the visual representation by: sending a request for a visual representation of the landmark to the server; - receiving a visual representation of the landmark from the server.

16. The mobile client device of any of claims 13 to 15, operable to transmit data describing the geographical position of the mobile client device to the server.

17. A system comprising a server operable to: receive from the mobile client device of any of claims 13 to 16 data describing: a geographical destination; and a geographical starting point, - use the data received from the mobile client device to prepare an itinerary for the mobile client device, the itinerary including: a route from the starting point to the destination; and a geographical zone associated with a landmark, transmit data describing the itinerary to the mobile client device; and respond to a determination that the mobile client device has passed through a boundary of a geographical zone by transmitting a visual representation of the landmark to the mobile client device.

18. The system of claim 17, wherein the server is operable to receive a request from the mobile client device for a visual representation of the landmark, and to respond by transmitting a visual representation of the landmark to the mobile client device.

19. The system of claim 17 or claim 18, wherein the visual representation is selected according to the monitored geographical position of the mobile client device.

20. The system of claim 19, wherein the visual representation is selected according to a tracking vector based upon a plurality of monitored geographical positions of the mobile client device.

21. The system of any of claims 17 to 20, wherein the visual representation is selected according to which boundary of the geographical zone the mobile client device is determined to have passed through.

22. The system of any of claims 17 to 21, wherein the itinerary includes a further geographical zone associated with the landmark, and wherein the server is operable to respond to a determination that the mobile client device has passed through a boundary of the further geographical zone by transmitting a visual representation of the landmark to the mobile client device.

23. The system of any of claims 17 to 22, wherein the determination that the mobile client device has passed through a boundary of a geographical zone associated with a landmark is made by comparing the monitored geographical position of the mobile client device with geographical positions within the geographical zone.

24. The system of any of claims 17 to 23, wherein the route is represented by a series of vectors.

25. The system of claim 24, wherein the determination that the mobile client device has passed through a boundary of the geographical zone associated with the landmark is made by resolving the monitored geographical position of the mobile client device onto a vector representing the route, and by comparing the resolved geographical position of the mobile client device with positions on the vector which coincide with positions within the geographical zone.

26. The system of any of claims 17 to 25, wherein each geographical zone is represented by a polygon in two or more dimensions.

27. The system of any of claims 17 to 26, wherein the server is operable to: receive positioning data from the mobile client device describing a geographical position of the mobile client device; - monitor the geographical position of the mobile client device using the positioning data; and determine whether the mobile client device has passed through a boundary of the geographical zone.

28. A method of providing navigational information on a mobile device, the method comprising: monitoring a geographical position of the mobile device using a positioning device of the mobile device; and the mobile device responding to a determination that the mobile device has passed through a boundary of a geographical zone associated with a landmark by: accessing a visual representation of the landmark; and displaying the visual representation on a display of the mobile device.

29. The method of claim 28, wherein the mobile device is a mobile client device, and wherein accessing the visual representation includes: transmitting to a server via a communications network a request for the visual representation; receiving the visual representation of the landmark.

30. The method of claim 29, further comprising a server: receiving from a mobile client device data describing: a geographical destination; and a geographical starting point, - using the data received from the mobile client device to prepare an itinerary for the mobile client device, the itinerary including: a route from the starting point to the destination; and a geographical zone associated with a landmark, transmitting data describing the itinerary to the mobile client device; and - responding to a determination that the mobile client device has passed through a boundary of a geographical zone by transmitting a visual representation of the landmark to the mobile client device.

31. A computer program product for implementing the method of any of claims 28 to 30.

32. The computer program product of claim 32 on a carrier medium.