WO2004100106A1

WO2004100106A1 - Method and apparatus for displaying map for navigation

Info

Publication number: WO2004100106A1
Application number: PCT/KR2003/002219
Authority: WO
Inventors: Won Ik Choi; Byeong Moo Kim
Original assignee: Thinkware Systems Corporation
Priority date: 2003-05-10
Filing date: 2003-10-22
Publication date: 2004-11-18
Also published as: KR100475279B1; AU2003273088A1; KR20040096684A

Abstract

The present invention relates to a method of displaying a map for navigation, wherein navigation using a mobile device can be efficiently performed by allowing the mobile device to efficiently request map information for navigation to a map information server connected to the mobile device via a mobile communications network and to receive the desired map information from the map information server. The present invention provides a method of displaying a map for navigation using a mobile device, comprising the steps of: storing first map information in a predetermined storage unit; extracting second map information from the first map information; displaying a map image associated with the second map information on a display unit of the mobile device; comparing a first area associated with the first map information and a second area associated with the second map information with each other; and requesting additional map information to a predetermined map information server in response to the comparison result. According to the present invention, there is provided a method of displaying a map for navigation wherein the navigation using a mobile device can be efficiently performed by allowing the mobile device to efficiently request map information for navigation to a map information server connected thereto via a mobile communications network and to receive relevant map information from the map information server.

Description

METHOD AND APPARATUS FOR DISPLAYING MAP FOR NAVIGATION

-Technical Field The present invention relates to a method of displaying a map for navigation in a mobile device. More particularly, the present invention relates to a method of displaying a map for navigation, wherein navigation using a mobile device can be efficiently performed by allowing the mobile device to efficiently request map information for navigation to a map information server connected to the mobile device via a mobile communications network and to receive the desired map information from' the map information server.

Background Art

A navigation system is a system that provides traffic information to vehicles such as automobiles using an artificial satellite and is also referred to as an automatic navigating system. Such a navigation system receives predetermined data from Global Positioning System (GPS) satellites orbiting the earth using a GPS receiver and calculates its own position based on the received data. There are a number of GPS satellites orbiting the earth. A navigation system can receive GPS signals from three GPS satellites no matter where the vehicle is located on the earth and calculate its own position based on the GPS signals received from the three GPS satellites. The navigation system provides a variety of traffic information to vehicles such automobiles based on the information on its own position calculated as such. Although this navigation system has been usually employed in the position determination for and the navigation of large carriers such as aircrafts or ships, it has recently been widely used even in the automobiles and the like. The navigation system provides a user with a variety of information including current position information of a vehicle, routing information from a current position to a destination of a vehicle, map information related to the position and routing information, traffic information and the like. Since using a map allows the user to easily understand the information on the current position and the like when the user receives the current position information and the like from the navigation system, the map information is generally provided to the user together with the current position information and the like.

According to a prior art, such map information has been provided to a user via a storage medium such as CD ROM or DVD ROM. Such a conventional navigation system has read, if desired, the map information stored in the storage medium such as CD ROM and then displayed the read information on a predetermined display unit. However, when the map information is to be updated in the conventional navigation system, the storage medium itself such as CD ROM should be replaced, and thus, this makes a user very troublesome whenever the map information is updated later on. In other words, there occur financial and time losses because the user should continue to purchase the CD ROM containing the updated map information from a CD ROM provider. Further, since it is impossible for the map information provider to provide a user with a CD ROM in which the updated map information has been reflected in real time, the updated map information (for example, when roads, buildings and the like are newly created or gone) cannot be provided to the user in real time. In addition, according to another prior art referred to as so-called "telematics," navigation services using mobile devices such as mobile phones have been provided. The telematics services can show a user the way to a destination using a voice. Further, when an accident happens to the user's car, the telematics services automatically track the position of the accident car using GPS satellites and transmit the information on the position of the accident car to 119 rescue services, a hospital or the like that is located nearest to the position of the accident car, so that rescue activities can be promptly performed. In the conventional navigation services using mobile phones, however, there is a problem in that the map information cannot be stored in the mobile phone due to its limited memory capacity. Therefore, since the vehicle position information, traffic information and the like have been provided to the user in the form of voice or text without the map information, it has caused inconvenience to the user when utilizing the conventional navigation system.

Accordingly, there is a need for a navigation system that can reflect updated map information related to roads etc. in real time by providing the map information to a mobile device via a communication network.

In such a case, there is still a need for a method of displaying a map for navigation, wherein navigation using a mobile device can be efficiently performed by T KR2003/002219

allowing the mobile device to efficiently request map information for navigation to a map information server connected to the mobile device via a mobile communications network and to receive the desired map information from the map information server.

Disclosure of Invention

The present invention is conceived to meet the aforementioned need. An object of the present invention is to provide a method of displaying a map for navigation, wherein navigation using a mobile device can be efficiently performed by allowing the mobile device to efficiently request map information for navigation to a map information server connected to the mobile device via a mobile communications network and to receive the desired map information from the map information server.

Another object of the present invention is to provide a method of allowing a mobile device to determine whether additional map information is required and to receive the additional map information from a map information server accordingly. A further object of the present invention is to provide a method of allowing a mobile device to estimate map information and to request the estimated map information to a map information server so that the map information can be efficiently transmitted.

A still further object of the present invention is to provide a method of displaying a map for navigation, wherein desired map information required by a display unit of a mobile device can be rapidly extracted from the map information sent to the mobile device from a map information server.

A still further object of the present invention is to provide a method of displaying a map for navigation, wherein by maintaining map information in a predetermined map information server and receiving desired map information substantially in real time via wireless communication, map information stored in the map information server can be updated even when the map information is updated, and the updated map information can be provided to a mobile device in real time.

According to an aspect of the present invention for achieving the objects and solving the problems in the prior art, there is provided a method of displaying a map for navigation using a mobile device, comprising the steps of storing first map information in a predetermined storage unit, extracting second map information from the first map information, displaying a map image associated with the second map information on a display unit of the mobile device, comparing a first area associated with the first map information and a second area associated with the second map information with each ohter, and requesting additional map information to a predetermined map information server in response to the comparison result. According to another aspect of the present invention, there is provided an apparatus for displaying a map for navigation, comprising a map information storage unit for storing first map information therein, a map information extraction unit for extracting second map information from the map information storage unit, a map image display unit for displaying a map image on a display unit of a mobile device on the basis of the second map information, and a control unit for comparing a first area associated with the second map information and a second area associated with the first map information with each other and requesting additional map information to a predetermined map information server in response to the comparison result.

Brief Description of Drawings

FIG. 1 is a diagram illustrating the connection relationship between a mobile device that requests map information for navigation and a map information server that provides the map information in response to the map information request according to the present invention. FIG. 2 is a flowchart illustrating the sequence of a process of displaying the map for navigation according to a preferred embodiment of the present invention.

FIG. 3 is a diagram illustrating the relationship between a map area corresponding to the map information stored in the map information server, a map area corresponding to the map information stored in the mobile device, and a map area displayed on the display unit of the mobile device.

FIG. 4a is a drawing showing second areas corresponding to the second map information that will be displayed on the display unit of the mobile device as the vehicle travels within a first area corresponding to the first map information stored in the storage unit of the mobile device. FIG. 4b is a drawing showing a virtual coordinate system on the first area in order to explain the process of extracting the second map area displayed on the display unit of the mobile device from the first area associated with the first map information stored in the mobile device.

FIGS. 5a and 5b are drawings illustrating a process of describing the first area associated with the first map information stored in the mobile device 120 by using a plurality of grids. FIGS. 6a and 6b are drawings illustrating a method of comparing the first area associated with the first map information and the second area associated with the second map information with each other.

FIG. 7 is a drawing showing the map information that is displayed on the display unit 124 of the mobile device 120. FIG. 8 is a block diagram illustrating an apparatus for displaying a map for navigation according to a preferred embodiment of the present invention.

Best Mode for Carrying Out the Invention

Hereinafter, a method and apparatus for displaying a map for navigation according to the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is a diagram illustrating the connection relationship between a mobile device that requests map information for navigation and a map information server that provides the map information in response to the map information request according to the present invention.

As shown in FIG. 1 , a method of displaying a map for navigation is implemented in such a manner that a map information server 100 transmits map information to a mobile device 120 of a user in a state where the map information server 100 in which the whole map information is maintained is connected to the mobile device 120 via a communications network 140.

The map information server 100 stores the whole map information for map display. The map information may be either image data where a map is represented in the form of images or vector data where a map is represented in the form of numerical values. Map data elements contained in the map information are associated with respective coordinate information.

If there is a request for map information from the mobile device 120, the map information server 100 sends the mobile device 120 the map information covering a range corresponding to the map information request through the mobile communications network 140. Further, if the user of the mobile device 120 requests the map information on a specific area, the map information server 100 searches for the map information on the specific area and transmits the searched map information to the mobile device 100. The data transfer rate of the map information may be adequately determined according to traffic transfer capability Of the communications network 140 and data storage capability of the mobile device 120. According to a preferred embodiment of the present invention, the amount of map information data to be transferred at a time should be set greater than the amount of map information data displayed on a display unit 124 of the mobile device 120. According to this embodiment, map information covering an area larger than the area of the map image displayed on the mobile device 120 can be received at a time. Thus, it is possible to minimize the number of requests for map information and resultant communications costs. The mobile device 120 is connected to a GPS receiver (not shown). The GPS receiver receives GPS signals from GPS satellites to determine the position of the mobile device 120. A storage unit 122 of the mobile device 120 stores map information received from the map information server. The display unit 124 of the mobile device 120 may be a LCD screen of a mobile device and allows a map desired by the user to be displayed.

FIG. 2 is a flowchart illustrating the sequence of a process of displaying the map for navigation according to a preferred embodiment of the present invention.

First map information corresponds to map information transmitted from the map information server 100 to the mobile device 120 and stored in the storage unit 122 of the mobile device 120 by the request of a user. Second map information corresponds to map information displayed on the display unit 124 of the mobile device 120. Further, a first area is an area on the map corresponding to a map image associated with the first map information, and a second area is an area on the map corresponding to a map image associated with the second map information. If the first map information is a map image, the first map information is coincident with the first area. If the second map information is a map image, the second map information is coincident with the second area. R2003/002219

According to an embodiment of the present invention, map information comprises vector map information. A map data element contained in the map information is mainly classified into a polygon map data element, polyline map data element, and POI(Point of Interest) information map data element. The polygon map data element is a map data element, corresponding to a river, a park and the like, in which the inside of a specific area is filled with a predetermined color when it is displayed on a map, and it can also be represented as a plurality of coordinate points. That is, the polygon map data element is produced by sequentially connecting all the plurality of the coordinate points, connecting the last coordinate point again to the first coordinate point and then filling the inside of a created polygon with a predetermined color. The polyline map data element is a map data element, corresponding to a road and the like, which is represented as a predetermined line when it is displayed on a map, and it can also be represented as a plurality of coordinate points. In other words, the polyline map data element is produced by sequentially connecting the plurality of the coordinate points. The POI information map data element is a map data element corresponding to a specific building, which is displayed as a predetermined icon when it is displayed on a map, and it is composed of a single coordinate point and a corresponding icon identifier. The POI information can be represented by displaying an icon associated with the icon identifier at a relevant coordinate point of the POI information map data element.

Hereinafter, respective steps of the method of displaying the map for navigation according to the present invention will be explained in detail with reference to the flowchart of FIG. 2.

The method of displaying the map for navigation comprises the steps of storing the first map information in a predetermined storage unit 122 of the mobile device 120 (SI 01), extracting second map information from the first map information (SI 02), displaying a map image associated with the second map information on a display unit 124 of the mobile device 120 (SI 03), comparing a first area associated with the first map information and a second area associated with the second map information (SI 04) with each other, requesting additional map information to a predetermined map information server 100 according to the comparison result (SI 05), receiving the additional map information from the map information server 100 (SI 06), and storing the received additional map information in the storage unit 122 (SI 07).

In step SI 01, the first map information received from the map information server 100 is first stored in the storage unit 122 such as memory that is embedded in the mobile device 120, in response to the map information request of the mobile device 120. The storage unit 122 may include a variety of storage media such as external memory other than the memory embedded in the mobile device 120. Map information on the whole map that the map information server 100 can provide is maintained in a predetermined database (not shown) of the map information server 100. The map information server 100 searches for predetermined map information corresponding to the map information request of the mobile device 120, i.e. the first map information, and transmits the searched map information to the mobile device 120. In such a case, the transmission of the first map information is accomplished via a mobile communications network. The transmitted first map information is stored in the storage unit 122.

Next, in step SI 02, map information associated with a map displayed on the display unit 124, i.e. the second map information, is extracted from the first map information (SI 02). This process corresponds to a process of extracting map information associated with a map, which is actually displayed on the display unit 124, from the first map information stored in the mobile device 120. According to an embodiment of the present invention, the map information associated with the map image that will be displayed on the display unit 124 of the mobile device 120 is determined based on navigation-related routing information. For example, if the next map is needed while a map related to a current position of a vehicle is being displayed on the display unit of the mobile device, it can be determined based on routing information of the vehicle which map should be the next map. Alternatively, if a user inputs information related to a specific area, a second map area to be displayed on the display unit of the mobile device can be determined based on coordinate information related to the specific area.

In step SI 03, the map image associated with the extracted second map information is displayed on the display unit 124 of the mobile device 120. If the second map information is map image information, the map image is displayed on the display unit 124 directly using the second map information. However, if the second map information is vector map information etc., the map image corresponding to the second map information is created through a predetermined calculating process and is then displayed on the display unit 124. An example of the map image displayed on the display unit 124 of the mobile device 120 is shown in FIG. 7.

In step S 104, a first area associated with the first map information and a second area associated with the second map information are compared with each other. The comparison process is to determine whether the map image corresponding to the second area is within the first area or approaches a predetermined boundary. The process of comparing the first area and the second area with each other will be described in detail with reference to FIGS. 3 to 6. FIG. 3 is a diagram illustrating the relationship between a map area corresponding to the map information stored in the map information server, a map area corresponding to the map information stored in the mobile device, and a map area displayed on the display unit of the mobile device.

As shown in FIG. 3, the map information on the whole map area, which can be provided by the map information server 100, is maintained in the map information server 100. The first area corresponding to the first map information that is received in response to the map information request of the mobile device 120 becomes a part of the whole map area. Further, the second area, which will be displayed on the display unit 124 of the mobile device 120, becomes a part of the first area. Accordingly, the sizes of these areas can be expressed as the following relationship: "the whole area > the first area > the second area".

FIG. 4a shows second areas 403a, 403b, 403c, 403d and 403e corresponding to the second map information that will be displayed on the display unit 124 of the mobile device 120 as the vehicle travels within a first area 401 corresponding to the first map information stored in the storage unit 122 of the mobile device 120.

The vehicle travels along a predetermined path 402. For instance, a user can request routing information to a navigation server based on a current position of the user's vehicle and a position of his/her destination, and receive relevant routing information from the navigation server. According to another embodiment of the present invention, the routing information may be calculated in the mobile device 120 based on the current position and the destination position.

As described above in connection with FIG. 3, the map area displayed on the R2003/002219

10 display unit 124 of the mobile device 120 is smaller than the whole map area of the map information stored in the storage unit 122 of the mobile device 120. In FIG. 4a, the map areas, which will be displayed on the display unit 124 of the mobile device 120 as the vehicle travels, are designated by reference numerals 403a, 403b, 403c, 403d and 403e.

As can be seen from FIG. 4a, however, the second area 403e adjoins the first area 401 at a boundary line of the first area. Therefore, since the mobile device 120 does not store the map information that will be displayed after the second area 403e has been displayed on the mobile device 120, the mobile device 120 should request additional map information to the map information server 100 and receive the additional map information. The present invention also provides a method of efficiently performing the request and reception of such additional map information.

FIG. 4b shows a virtual coordinate system on the first area 401 in order to explain the process of extracting the second map area displayed on the display unit 124 of the mobile device 120 from the first area associated with the first map information stored in the mobile device 120.

Referring to FIG. 4b, when the first map information stored in the mobile device 120 is converted into a map image by means of a predetermined means (e.g., an imaging program, a mapping tool and the like), the first area 401 corresponding to the map image is illustrated on the virtual secondary coordinate system. In other words, assuming that the horizontal direction of the first area 401 is set as an X axis and the vertical direction of the first area 401 is set as an Y axis, a specific point of the first area 401 can be defined as a corresponding (X, Y) coordinate value. The virtual coordinate system is defined in the same manner as a typical secondary coordinate system. For example, the left bottom of the coordinate system is specified as (0, 0) and the X- and Y-coordinate values are increased toward the right and upper directions.

The second area 402 corresponds to an area of the map image displayed on the display unit 124 of the mobile device 120. In FIG. 4b, a current position of a mobile device (or a current position of a vehicle mounted with the mobile device) can be specified as (xj, yi) and a polyline indicating a road on which the vehicle travels can also be specified as (x₂, 0)-(x₃, y₃). Therefore, each of all map elements of the second area displayed on the display unit 124 has the (X, Y) coordinate value corresponding to the virtual coordinate system of the first area.

As shown in FIG. 4b, a coordinate for the boundary line of the second area 402 associated with the map image displayed on the display unit 124 of the mobile device 120 can be determined on the basis of the coordinate for the first area 401. According to an embodiment of the present invention, a first boundary coordinate associated with the first area 401 is a coordinate for all the boundary lines of the first area 401, and a second boundary coordinate associated with the second area 402 is a coordinate for all the boundary lines of the second area 402. According to another embodiment of the present invention, the first and second areas 401 and 402 are configured to take the shape of a rectangle, the first boundary coordinate associated with the first area 401 corresponds to coordinates of vertexes of the rectangle associated with the first area, and the second boundary coordinate associated with the second area 402 corresponds to coordinates of vertexes of the rectangle associated with the second area. According to this embodiment, there is an advantage in that the mobile device 120 can determine whether to request additional map information even while maintaining a boundary coordinates to the minimum.

FIGS. 5a and 5b are views illustrating a process of describing the first area associated with the first map information stored in the mobile device 120 by using a plurality of grids. Here, each of the grids corresponds to a unit area obtained by dividing the first area into a predetermined number of rectangular cells. According to a preferred embodiment of the present invention, each of the grids has the unit area of the same size, as shown in FIG. 5 a. According to another embodiment of the present invention, the grids may take the different shape and have the different size. Further, a predetermined number is assigned to each of the unit grids.

According to this embodiment, it is possible to easily search for at least one unit grid including the X, Y coordinate value of the second area, preferably a second boundary coordinate. Thus, since the coordinate value of the second area can be compared and determined within the only selected unit grid rather than within the whole first area when extracting the second area, the comparison and determination time taken for the extraction of the second area can be significantly reduced. That is, the second area can be more rapidly extracted from the first area by assigning the grid number to 03 002219

12 each of the grids in connection with the second boundary coordinate and comparing the coordinate value of the second area with the selected grids.

According to an embodiment of the present invention, first map information is configured to include a predetermined number of rectangular grids having the same size. After a boundary coordinate associated with second map information is first determined, it is determined which cell includes the boundary coordinate based on information on the horizontal and vertical sizes of each grid and the boundary coordinate associated with the second map information. Then, map information associated with the determined cell is extracted. In other words, each of the grids has a size of 100 x 100, and the first area is divided into 10 x 10 grids, i.e. total 100 grids. In such a case, the area of each grid can be easily calculated. For example, it can be easily known that a coordinate (127, 127) is included in an eleventh grid. Therefore, it can be immediately understood to which grid a specific coordinate belongs without comparing the specific coordinate with those of all the grids. FIG. 5b illustrates a method of searching for a grid corresponding to an area displayed on the mobile device.

A second map area that will be displayed on the display unit of the mobile device is first determined based on the routing information and the like. For example, if the next map is needed while a map related to the current position of the vehicle is being displayed on the display unit of the mobile device, it can be determined based on the routing information of the vehicle which map should be the next map. Alternatively, if the user inputs information related to a specific area, a second map area to be displayed on the display unit of the mobile device can be determined based on the coordinate information related to the specific area. If the coordinates of 4 vertexes of the second map area to be displayed on the display unit of the mobile device are (120, 120), (120, 270), (270, 270), and (270, 120), the numbers of grids to which the vertexes belong become 11, 12, 21 and 22, respectively. Alternatively, grids to which the coordinates belong may be identified on the basis of all coordinates on the boundary line of the second map area including the four vertexes of the second map area.

FIGS. 6a and 6b illustrate a method of comparing the first area associated with the first map information and the second area associated with the second map 2219

13 information with each other.

Referring to FIG. 6a, it is determined whether at least one second boundary coordinate associated with the second area corresponding to an area of a map displayed on the display unit 124 of the mobile device 120 matches at least one first boundary coordinate associated with a first area corresponding to an area of a map stored in the storage unit 122 of the mobile device 120. FIG. 6a specifically shows a case where the first and second boundary coordinates match each other at reference numeral 603. When at least one first boundary coordinate and the at least one second boundary coordinate match each other as described above, the mobile device 120 requests the additional map information to the map information server 100 (SI 05, see FIG. 2).

FIG. 6b shows a case where the mobile device requests the additional map information beforehand under the predetermined conditions by using a prefetch scheme according to another embodiment of the present invention. In other words, it is determined whether the difference between at least one of the second boundary coordinates of the second area 602 and at least one of the first boundary coordinates of the first area 601 falls within a predetermined coordinate value. If the difference is within the predetermined coordinate value, the mobile device 120 requests the additional map^' information to the map information server 100 (SI 05). According to this embodiment, since desired map information is received in advance, the user can receive the map information without interruption even when it takes a lot of time to receive the map information from the server.

The boundary coordinate may be all the coordinates defining the boundary of the first or second area. According to another embodiment of the present invention, the first and second areas are configured to take the shape of a rectangle and the boundary coordinates become the coordinates of vertexes of a rectangle of each area. If the size of a grid defining the first area is sufficiently larger than that of the second area, a grid to which the second area belongs can be identified with only the vertex coordinates of the rectangle of the second area. Further, since whether to make a request for transmission of the additional map information can be determined based on only the four vertex coordinates rather than all the boundary coordinates, there is an advantage in that CPU's burden is reduced.

Hereinafter, steps following the step SI 05 will be described in detail with reference to FIG. 2 again.

A program installed in the mobile device 120 requests new map information to the map information server 100 according to the determination result in step SI 04

(SI 05). In such a case, the new map information is determined based on the routing information for navigation. In other words, the program requests map information related to an area to which a vehicle is expected to travel.

In step SI 06, the new map information is sent to the mobile device 120 in response to the map information request of the mobile device 120. In step SI 07, the received additional map information is stored in the storage unit 122 of the mobile device 120. Consequently, as the vehicle mounted with the mobile device 120 travels, a series of the processes are repeatedly performed and a map image of the map information can be displayed on the display unit 124 of the mobile device 120.

A method of displaying a map using extents according to an embodiment of the present invention will be described with reference to FIG. 4a again. In FIG. 4a, extents 404a, 404b, 404c, 404d and 404e that correspond to the second areas 403a, 403b, 403c, 403d and 403e, respectively, are shown. If a travel direction of the vehicle is coincident with the X-axis, the second areas are coincident with the extents, respectively (for example, in case of 403a and 403e). Each of the extents is a rectangular area including a first vertex located at a maximum X coordinate and a maximum Y coordinate of the four vertexes of the rectangular map image associated with the second area, a second vertex located at the maximum X coordinate and the minimum Y coordinate thereof, a third vertex located at the minimum X coordinate and the maximum Y coordinate thereof, and a fourth vertex located at the minimum X coordinate and the minimum Y coordinate thereof. In step SI 04, these extents are compared with the first area related to the first map information by using the coordinates of the first to fourth vertexes as the second boundary coordinates.

FIG. 7 shows the map information that is displayed on the display unit 124 of the mobile device 120. In this figure, a triangle 701 located at the center of the display unit 124 indicates either a mobile device for receiving the map information or a vehicle mounted with the mobile device.

A heading-up map display shown in FIG. 7 is a map display method illustrated in the embodiment of the present invention. In such a case, the top direction of the display unit 124 always becomes a direction in which a mobile device or a vehicle mounted with the mobile device moves or travels. Accordingly, being the triangle stationary, the map including the moving path is displayed while the map image is rotated.

According to another embodiment of the present invention in which a north-up map display is used, the north is always toward the top direction when displaying the map.

FIG. 8 is a block diagram illustrating an apparatus for displaying a map for navigation according to a preferred embodiment of the present invention.

Referring to FIG. 8, the apparatus for displaying the map for navigation 901 of the present invention comprises a map information storage unit 902 for storing first map information, a map information extraction unit 903 for extracting second map information from the map information storage unit 902, a map image display unit 904 for displaying a map image on the display unit 124 of the mobile device 120 on the basis

, of the second map information, and a control unit 905 for comparing an area associated with the second map information and an area associated with the first map information and requesting additional map information to a predetermined map information server in response to the comparison result. The control unit 905 compares one or more first boundary coordinates associated with the first area and one or more second boundary coordinates associated with the second area with each other, and requests the additional map information to the predetermined map information server when at least one of the second boundary coordinates matches at least one of the first boundary coordinates. Alternatively, the control unit 905 compares one or more first boundary coordinates associated with the first area and one or more second boundary coordinates associated with the second area and requests the additional map information to the predetermined map information server when the difference between at least one of the second boundary coordinates and at least one of the first boundary coordinates falls within a predetermined coordinate value.

The preferred embodiments of the present invention include a computer-readable recording medium containing program instructions for executing the operations implemented by a variety of computers. The computer-readable recording medium may contain program instructions, data files, data structures, or a combination thereof. The program instructions may be ones that are specially designed or written for the present invention or may be ones that are well known to those skilled in the field of computer software. For example, the computer-readable recording medium includes a magnetic medium such as a hard disk, a floppy disk and a magnetic tape, an optical medium such as CD-ROM and DVD, a magneto-optical medium such as a floptical disk, and hardware devices such as read only memory (ROM), random access memory (RAM) and flash memory that are specially configured to store and execute the program instructions. The medium may be a transfer medium such as an optical or metal line and waveguide, including a carrier wave that transmits signals for specifying the program instructions, data structures and the like. Examples of the program instructions may include high-level language codes executable by a computer using an interpreter as well as machine language codes such as those written by a compiler. Although the present invention has been illustrated and described with reference to the exemplified embodiments and the drawings, the present invention is not limited thereto. It will be apparent that those skilled in the art to which the present invention pertains can make various changes and modifications thereto. Therefore, the present invention should be construed only based on the appended claims and equivalents thereof will fall within the scope of the present invention.

Industrial Applicability

According to the present invention as described above, there is provided a method of displaying a map for navigation wherein the navigation using a mobile device can be efficiently performed by allowing the mobile device to efficiently request map information for navigation to a map information server connected thereto via a mobile communications network and to receive relevant map information from the map information server.

Further, according to the present invention, the mobile device can determine whether additional map information is required and receive the additional map information from the map information server.

Further, according to the present invention, the map information can be efficiently transmitted by allowing a mobile device to estimate map information and to request the estimated map information to a map information server.

Further, according to the present invention, there is provided a method of displaying a map for navigation, wherein desired map information required by a display unit of a mobile device can be rapidly extracted from the map information sent to the mobile device from a map information server.

Further, according to the present invention, by maintaining map information in a predetermined map information server and receiving desired map information substantially in real time via wireless communication, map information stored in the map information server can be updated even though the map information is updated, and the updated map information can be provided to a mobile device in real time.

Claims

R2003/002219CLAIMS

1. A method of displaying a map for navigation using a mobile device, comprising the steps of: (a) storing first map information in a predetermined storage unit;

(b) extracting second map information from the first map information;

(c) displaying a map image associated with the second map information on a display unit of the mobile device;

(d) comparing a first area associated with the first map information and a second area associated with the second map information with each other; and

(e) requesting additional map information to a predetermined map information server in response to the comparison result.

2. The method as claimed in claim 1 , further comprising the steps of: (f) receiving the additional map information from the map information server; and

(g) storing the received additional map information in the predetermined storage unit.

3. The method as claimed in claim 1, wherein the first map information comprises a predetermined number of rectangular cells.

4. The method as claimed in claim 3, wherein each of the rectangular cells has the same size.

5. The method as claimed in claim 4, wherein the first map information comprises the predetermined number of the rectangular cells having the same size, and step (b) comprises the steps of: determining a boundary coordinate associated with the second map information; determining a cell including the boundary coordinate based on information on horizontal and vertical sizes of the cell and the boundary coordinate; and extracting map information associated with the determined cell.

6. The method as claimed in claim 3, further comprising the step of (h) determining a boundary coordinate associated with a map image to be displayed on the display unit of the mobile device, wherein step (b) comprises the steps of: determining which cell includes the boundary coordinate among the plurality of the cells contained in the first map information; and extracting map information associated with the determined cell.

7. The method as claimed in claim 6, wherein step (h) is performed based on routing information associated with the navigation.

8. The method as claimed in claim 7, wherein the map image takes the shape of a rectangle, and the boundary coordinate corresponds to coordinates of vertexes of the rectangle.

9. The method as claimed in claim 1, wherein step (d) comprises the step of comparing one or more first boundary coordinates associated with the first area and one or more second boundary coordinates associated with the second area with each other.

10. The method as claimed in claim 9, wherein step (e) comprises the step of requesting the additional map information to the predetermined map information server when at least one of the second boundary coordinates matches at least one of the first boundary coordinates.

11. The method as claimed in claim 9, wherein step (e) comprises the step of requesting the additional map information to the predetermined map information server when the difference between at least one of the second boundary coordinates and at least one of the first boundary coordinates falls within a predetermined coordinate value.

12. The method as claimed in claim 9, wherein each of the first and second areas takes the shape of a rectangle, the first boundary coordinate corresponds to coordinates of vertexes of the rectangle associated with the first area, and the second boundary coordinate corresponds to coordinates of vertexes of the rectangle associated with the second area.

13. The method as claimed in claim 9, wherein the map image associated with the second map information takes the shape of a rectangle; the second area associated with the second map information is a rectangular area including a first vertex located at a maximum X coordinate and a maximum Y coordinate of four vertexes of the map image, a second vertex located at the maximum X coordinate and the minimum Y coordinate thereof, a third vertex located at the minimum X coordinate and the maximum Y coordinate thereof, and a fourth vertex located at the minimum X coordinate and the minimum Y coordinate thereof; and the second boundary coordinate corresponds to coordinates of the first to fourth vertexes.

14. The method as claimed in claim 1, wherein the area associated with the first map information is larger than that associated with the second map information.

15. The method as claimed in claim 1, wherein step (e) comprises the steps of: determining additional map information which will be requested to the map predetermined information server based on routing information associated with the navigation; and requesting the determined additional map information to the predetermined map information server.

16. A computer-readable recording medium in which a program for implementing a method according to any one of claims 1 to 15 in a computer is recorded.

17. An apparatus for displaying a map for navigation, comprising: a map information storage unit for storing first map information therein; a map information extraction unit for extracting second map information from the map information storage unit; a map image display unit for displaying a map image on a display unit of a mobile device on the basis of the second map information; and a control unit for comparing a first area associated with the second map information and a second area associated with the first map information with each other and requesting additional map information to a predetermined map information server in response to the comparison result.

18. The apparatus as claimed in claim 17, wherein the control unit compares one or more first boundary coordinates associated with the first area and one or more second boundary coordinates associated with the second area with each other and requests the additional map information to the predetermined map information server when at least one of the second boundary coordinates matches at least one of the first boundary coordinates.

19. The apparatus as claimed in claim 17, wherein the control unit compares one or more first boundary coordinates associated with the first area and one or more second boundary coordinates associated with the second area with each other and requests the additional map information to the predetermined map information server when the difference between at least one of the second boundary coordinates and at least one of the first boundary coordinates falls within a predetermined coordinate value.