WO2004099719A1

WO2004099719A1 - Method and system for providing map information to mobile device

Info

Publication number: WO2004099719A1
Application number: PCT/KR2003/002218
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: KR20040096683A; AU2003273087A1; KR100540397B1; JP2006526159A

Abstract

The present invention relates to a method of efficiently transmitting a plurality of levels of map information to a mobile device so that a map can be magnified or reduced on the mobile device. The method for providing map information to a mobile device of the present invention, is characterized in that comprises the steps of maintaining a map information database containing a plurality of map data elements each of which is associated with coordinate information and level information; receiving a request for map information from the mobile device; searching for the map data elements associated with position information corresponding to the map information request; and transmitting the searched map data elements to the mobile device along with the display level information associated with the searched map data elements. According to the present invention, when map information is provided to a mobile device, an amount of data to be transmitted can be minimized by dividing a map corresponding to a single area into a plurality of levels and transmitting map information data common to the respective levels in a shared manner.

Description

METHOD AND SYSTEM FOR PROVIDING MAP INFORMATION TO

MOBILE DEVICE

Technical Field The present invention relates to a method for providing map information to a mobile device, and more particularly, to a method for efficiently providing a plurality of levels of map information to a mobile device so that a map can be displayed with magnification or reduction on the mobile device.

Background Art

Recently, due to the provision of services through a communication network, a chance to search information under wireless communication environment such as portable computers and mobile phones has increased. Thus, a user can search desired information and obtain desired services anywhere or anytime while freely moving. A navigation system is a system that provides information of navigation for vehicles such as automobiles using an artificial satellite and is also referred to as an automatic (car) 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 navigation system is located on the earth and calculate its own position based on the GPS signals received from the three GPS satellites. The navigation system can provide a variety of navigation 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 the map information allows the user to easily recognize 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 necessary, the map information stored in the storage medium such as CD ROM and then displayed the read information on a predetermined display means. 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 a traffic 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.

Furthermore, in order to support magnification and reduction of a map in connection with geographical information in a mobile device, it is necessary to provide the map information according to its respective levels. Referring to FIG. 3, a user wishes to receive a map on the same area with a plurality of levels. Further, the map of each level contains information other than a map on which an image in one level was simply magnified or reduced. For example, "Seowon Building" shown in FIG. 3 (b) is not displayed on a map image in the other level. Accordingly, there is a need for a method of efficiently transmitting a plurality of levels of map information when the map information is forwarded from a map information providing server to a mobile device of the user.

Disclosure of Invention The present invention is conceived to solve the aforementioned problems in the prior art. An object of the present invention is to provide a method and system for providing map information, wherein when map information is provided to a mobile device, an amount of data to be transmitted can be minimized by dividing a map corresponding to a single area into a plurality of levels and transmitting map information data common to the respective levels in a shared manner.

Another object of the present invention is to provide a method and system for providing map information, wherein when a plurality of levels of map images are provided to a user, the map image corresponding to each level is not merely magnified or reduced but the information suitable to each level can be displayed. A further object of the present invention is to provide a method and system for providing map information, wherein when map information is provided to the mobile device, a map corresponding to a single area is divided into a plurality of levels and map data elements are maintained to correspond to the plurality of the divided levels, whereby a map of a different level can be immediately displayed on the mobile device without any additional download if the device intends to display the map of the different level after receiving map information on a single area. 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 for providing map information to a mobile device, comprising the steps of maintaining a map information database containing a plurality of map data elements each of which is associated with coordinate information and display level information; receiving a request for map information from the mobile device; searching for the map data elements associated with position information corresponding to the map information request; and transmitting the searched map data elements to the mobile device along with the display level information associated with the searched map data elements. The method for providing map information to the mobile device according to the present invention may further comprise the steps of the mobile device's receiving the display level information from a user; the mobile device's searching for map data elements associated with the display level information among the stored map data elements; and the mobile device's displaying a map image associated with the searched map data elements on the display means of the mobile device.

According to another aspect of the present invention, there is provided a method for providing map information in a mobile device, comprising the steps of requesting a predetermined map information providing server to forward map information that is associated with position information; receiving map data elements associated with the position information from the map information providing server, wherein each of the map data elements is associated with coordinate information and level information; storing the received map data elements; determining a display level of a map image to be displayed on a display means of the mobile device; searching for map data elements associated with the determined display level among the stored map data elements; and displaying a map image associated with the searched map data elements on the display means of the mobile device.

Further, a method for providing map information according to an aspect of the present invention may comprise the steps of: maintaining a plurality of map data elements associated with display level information in a map information database according to the display level information; receiving a request for map information from the mobile device; searching for the map data elements by the display level information associated with position information corresponding to the map information request; and transmitting the searched map data elements by the display level information to the mobile device.

Further, a system for providing map information to according to an aspect of the present invention, may comprise a map information database for maintaining a plurality of map data elements according to display levels, said map data element being associated with the display levels; a receive unit for receiving a request for map information including position information from the mobile device; a search unit for searching the map information database for the map data elements associated with the position information in response to the map information request; and a transmit unit for transmitting the searched map data elements to the mobile device along with the level information associated with the searched map data elements.

Brief Description of Drawings The above and other objects, features and advantages of the present invention will become apparent from the following description of preferred embodiments given in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram illustrating the configuration for providing map information to a mobile device via a communication network according to the present invention.

FIGS. 2a to 2d are drawings showing a conceptual configuration of the map information database and the icon database in the map information providing server according to an embodiment of the present invention.

FIG. 3 is a drawing showing a map displayed in each display level on the basis of the map data elements shown in FIG. 2 according to a preferred embodiment of the present invention.

FIG. 4 is a flowchart illustrating a process of allowing a map information providing server to search a predetermined map data element stored in a map information database according to an embodiment of the present invention. FIG. 5 is a drawing showing a data packet format in a case where the map data elements searched are sent to the mobile device. FIG. 6 is a flowchart illustrating a process of displaying map images based on the map data elements stored in the mobile device.

FIG. 7 shows the map information database according to another embodiment of the present invention. FIG. 8 is a conceptual view illustrating a process of maintaining map data elements and sending them to a mobile device according to a further embodiment of the present invention.

FIG. 9 is a block diagram of a general-purpose computer system that can be employed to configure the map information providing server according to the present invention.

Best Mode for Carrying Out the Invention

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. FIG. 1 is a block diagram illustrating the configuration for providing map information to a mobile device via a communication network according to the present invention.

Referring to FIG. 1, a map information providing server 110 comprises a server- side database including a map information database 111 that stores a plurality of map data elements therein and an icon database 112 that stores icons and icon identifiers therein, a server-side receive unit 113 that receives a request for map information including position information from a mobile device 121 via a communication network 130, a server-side search unit 114 that searches the map information database 111 for the map data elements associated with the position information in response to the map information request, and a server-side transmit unit 115 that transmits the map data elements searched in the search unit 114 to the mobile device 121 along with display level information associated with the searched map data elements.

The map information database 111 includes a polygon database, a polyline database and a point database. The map information database 111 and the icon database 112 will be described in detail later with reference to FIG. 2.

A system 120 of the mobile device includes a device receive unit 122 that receives the map data elements from the map information providing server 110 via the communication network 130, device storage unit 123 that stores the received map data elements therein, a device search unit 124 that searches the map data elements stored in the device storage unit 123 for a map data element associated with predetermined display level information, and a device display unit 125 that displays a map image associated with the searched map data element on the mobile device 121.

FIGS. 2a to 2d show a conceptual configuration of the map information database and the icon database in the map information providing server according to an embodiment of the present invention. 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, a polyline map data element and a POIfPoint 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. To allow a width of the line to be changed in a polyline map data element, information on the line width may be further included. The POI information map data element is a map data element, corresponding to a specific building, a gas station, a restaurant, a movie theater, Point of Interest (POI) and the like, 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. POI information can be represented by displaying an icon associated with the icon identifier at the relevant coordinate point of the POI information map data element. FIG. 2a shows information on the polygon map data element stored in the polygon database. The polygon map data element comprises a polygon identifier, a color value, a level index, the number of polygon vertexes, and coordinates of the polygon vertexes.

The polygon identifier corresponds to an identifier for identifying an individual polygon. For example, a polygon identifier "0100" may be assigned to "Seolleung Park" and a polygon identifier "0101" may be assigned to "A apartment complex". The color value corresponds to the value of a color used to fill the inside of a closed curve that is obtained by sequentially connecting all the polygon vertex coordinates. Each color value is associated with color information. For instance, "00FF00" and "CC6600" are specified to indicate green and brown, respectively, and these color values are stored in the polygon database. The level index corresponds to information on a level at which the polygon is displayed. A level index "9, 10" corresponding to a polygon identifier "0100" means that the polygon is displayed in ninth and tenth levels. According to an embodiment of the present invention, the level index may be implemented in the form of a flag. For example, when a polygon has a level index of 3 bits with respect to the ninth, tenth and eleventh levels, the polygon is configured in such a manner that the most significant bit corresponds to the ninth level, the second bit corresponds to the tenth level and the least significant bit corresponds to the eleventh level. In this case, a level index corresponding to the "9, 10" level becomes "110" and a level index corresponding to the "9, 11" level becomes "101". The number of the vertexes corresponds to the number of vertexes used to define the line of a polygon. The coordinates of the vertexes correspond to the coordinates of vertexes used to decide the line of a polygon. At this time, vertex coordinate information as many as the number of vertexes is contained in the polygon database. A polygon map data element corresponding to a polygon identifier can be displayed on a map by sequentially connecting the vertex coordinate points, connecting the last vertex coordinate again to the first vertex coordinate and then filling the inside of the closed curve with a color corresponding to the color value.

FIG. 2b shows information on the polyline map data element stored in the polyline database. The information on the polyline map data element contains a polyline identifier, a color value, a level index, the number of vertexes, coordinates of the vertexes and a line width.

The polyline identifier corresponds to an identifier for identifying an individual polyline. The color value corresponds to the value of a color for a line obtained by sequentially connecting all the vertex coordinates of a polyline. The level index corresponds to information on a level at which the polyline is displayed. The number of the vertexes corresponds to the number of vertex coordinates used to define a polyline. The vertex coordinates correspond to the coordinates of vertexes used to define the polyline. A line that is obtained by sequentially connecting all the vertexes and then displayed as a color corresponding to the color value becomes a polyline. The line width corresponds to a value for the width of a line that is obtained by connecting the vertexes. The line width is used to display roads on a map in such a manner that broad roads such as express highways have a large width and narrow roads such as district roads also have a small width.

FIG. 2c shows information on the POI information data elements stored in the POI information database. The information on the POI information data elements contains a point identifier, a level index, an icon identifier, an output coordinate, a text, and a text length.

The point identifier corresponds to an identifier for identifying individual POI information. The level index corresponds to information on a level at which the POI information is displayed. The icon identifier corresponds to an identifier for an icon that is displayed as an image when the POI information is displayed on a map. The output coordinate corresponds to information on a coordinate of the icon on the map where the icon corresponding to the POI information is displayed. The text corresponds to text information displayed on a map in conjunction with the POI information. Referring to FIG. 3, the text information may include texts such as "Ewha Womans University Station" and "Yeonghwa Madang". The text length corresponds to information on the length of a text.

FIG. 2d shows the relationship between the icons and the icon identifiers stored in the icon database. For example, an icon indicating a building corresponds to an icon identifier "1" and an icon indicating a subway station corresponds to an icon identifier "2". In a case where POI information such as a building is displayed on a map, an icon corresponding to the POI information can be searched from the icon database by using an icon identifier stored in the POI information database.

FIG. 3 shows a map displayed in each display level on the basis of the map data elements shown in FIG. 2 according to a preferred embodiment of the present invention, wherein (a) shows a ninth-level map, (b) shows a tenth-level map and (c) shows an eleventh-level map.

Reference numeral 301 designates Ewha Womans University's campus that is represented as a polygon data element, reference numeral 302 designates a road that is represented as a polyline data element, and reference numeral 303 designates a place called "Yeonghwa Madang" that is represented as a POI information data element.

The relationship between the ninth-, tenth- and eleventh-level map images is relationship for providing different map information on the same area. For example, if a user requests "magnification" while viewing the tenth-level map, the eleventh-level map is provided to the user. Alternatively, if the user requests "reduction" while viewing the tenth-level map, the ninth-level map is provided to the user. At this time, it should be noted that the map provided upon the request of the "magnification" or "reduction" thereof is not a map image that is merely magnified or reduced. In other words, although it is shown that the ninth-level map includes an area covering the tenth- level map, the POI information called "Yeonghwa Madang" is displayed not on the ninth-level map but on the tenth-level map. The present invention is employed to efficiently support a case where a plurality of map images should be provided for the same area in a mobile device.

As seen from the above maps, "Yeonghwa Madang" that is one of the POI information is displayed only on the tenth- and the eleventh-level maps. Therefore, the POI information data element regarding "Yeonghwa Madang" has the tenth- and eleventh-level indexes. Similarly, the POI information data element regarding "Seowon Building" of the tenth level has a tenth-level index and is thus displayed only on the tenth-level map.

FIG. 4 is a flowchart illustrating a process of allowing a map information providing server to search a predetermined map data element stored in a map information database and then to send the searched information to a mobile device and allowing the mobile device to store the received map data element therein according to an embodiment of the present invention when the mobile device is connected to the map information providing server in order to make a request for desired map information.

An embodiment of the present invention will be now described in detail with reference to FIG. 4.

A mobile device 121 requests an access to a map information providing server 110 (S401). The map information providing server 110 confirms the access request of the mobile device 121 and then authenticates the access of the mobile device 121 (S402). After the authentication for the mobile device 121 has been completed, the map information providing server 110 transmits all the icons and icon identifiers stored in the icon database 112 to the mobile device 121 (S403). At this time, the map information providing server 110 transmits all the icons and icon identifiers to the mobile device 121 in step S403. Thus, it is not necessary to send the icon images again even if the mobile device 121 requests a map again. The mobile device 121 causes the received icon images o be stored in a predetermined storage unit (S404). The mobile device 121 does not have to additionally download the icon images, since the mobile device 121 can search the previously stored icon images using the icon identifiers and display the searched icon images when the mobile device causes the icons to be displayed on its display unit. Since icon images are generally very small and have a small amount of data, they do not greatly occupy a storage space of the mobile device 121 even though all the icon images necessary for the provision of the map images are stored in the mobile device.

The mobile device 121 requests the map information providing server 110 to forward the map information including the position information (S405). In other words, the mobile device 121 requests the desired map information to the map information providing server 110. At this time, in order to receive only the map information relevant to a specific area, the mobile device 121 transmits the position information related to the specific area together with the map information. The position information may be specific coordinate information (for example, information on the coordinates of 4 vertexes of a specific area in a case where the area has been partitioned into a rectangular form), position information including a name of a specific administrative section, or information on a specific place. For example, when receiving the map information including the position information called "Sinchon Station", the map information providing server 110 transmits information on the map of a specific area around "Sinchon Station" to the mobile device 121. The map information providing server 110 receives the map information request and then searches the map information database 111 (S406). Since the position information is included in the map information request, the map information providing server 110 searches the map information database 111 for the map data elements based on the position information. For instance, if the position information is 4 coordinates of the vertexes of a map requested by the mobile device 121, the map information providing server 110 searches for all the map data elements having coordinates within boundary lines of the map. The map information providing server 110 searches the polygon database, the polyline database and the POI information database for all the map data elements associated with the position information. The map information providing server 110 transmits the searched map data element to the mobile device 121 (S407). The mobile device 121 receives the map data element and causes the received map data elements to be stored in the device storage unit 123 thereof (S408).

FIG. 5 shows a data packet format in a case where the map data elements searched in step S407 are sent to the mobile device.

The transmit data packet is mainly composed of a header and map data. The header contains the number of polygons, the number of polylines, the number of points (the number of POI information), and group information. The number of polygons corresponds to the number of polygon map data elements among the map data elements to be transmitted. The number of polylines corresponds to the number of polyline map data elements among the map data elements. The number of POI information corresponds to the number of POI information map data elements among the map data elements. The group information may contain the number of levels, the scale of magnification and/or reduction, a grid number and the like. The number of levels corresponds to the number of levels associated with the map data elements, the scale of magnification and/or reduction corresponds to the scale of magnification and/or reduction associated with the levels, and the grid number corresponds to an identification number of each rectangular unit when the map information is transmitted in the form of a plurality of the rectangular units.

The map data contains point map data elements (POI information map data elements), polygon data elements and polyline data elements. The number of the POI information map data elements is the same as that of the points contained in the header. Information contained in the POI information map data element is the same as the information contained in the POI information database that has been described with reference to FIG. 2c. The number of the polygon map data elements is the same as that of the polygons contained in the header. Information contained in the polygon map data elements is the same as the information contained in the polygon database that has been described with reference to FIG. 2a. The number of the polyline map data elements is the same as that of the polylines contained in the header. Information contained in the polyline map data elements is the same as the information contained in the polyline database that has been described with reference to FIG. 2b.

The mobile device 121 receives a data packet containing the aforementioned map data element and stores the packet in the device storage unit 123. The format of data stored in the device storage unit 123 may be the same as that of the data packet or the format modified in accordance with characteristics of the mobile device 121. FIG. 6 is a flowchart illustrating a process of displaying map images based on the map data elements stored in the mobile device.

The mobile device 121 causes the map information data elements received from the map information providing server 110 to be maintained in the device storage unit 123 (S601). The map information data elements correspond to data that the mobile device 121 have received in response to a request for the map information associated with the position information after transmitting the map information request to the map information providing server 110. Each of the received map information data elements is associated with the coordinate information and display level information.

A display level of a map image to be displayed on the device display unit 125 in the mobile device 121 is determined (S602). If a user requested a ninth-level map image, the display level is a ninth level. Further, in a case where the map information corresponding to a neighboring area should be displayed on the device display unit 125 while a tenth-level map image is provided to a user (for example, if a vehicle of the user enters the neighboring area beyond a specific area that is currently being displayed), the map image of the same display level as the current display level can also be provided to the user.

The mobile device 121 searches for a map data element corresponding to the display level among the stored map data elements (S603). Since the map data element is associated with the display level information, the mobile device 121 can search for only the map data element associated with the display level information corresponding to the display level.

A map image associated with the searched map data element is displayed on the device display unit 125 of the mobile device 121 (S604). The device display unit 125 may include a liquid display device (LCD) of a mobile device. If the map data element is composed of a map image, the searched map data element can be immediately displayed on the device display unit 125 without additional conversion process. If the map data element is vector map information etc., a map image is created based on the map data element and then displayed on the device display unit 125. In a case where the POI information is displayed, an icon is displayed with reference to the previously received icon information. Since the information on the icon identifiers and icon images has been stored in the device storage unit 123 of the mobile device 121 in step S404, the device display unit 125 uses icon identifiers associated with the POI information to search the stored icon image information and displays the icon image information onto a relevant coordinate when displaying the POI information.

Steps S605 to S607 are a process of supporting a case where a user of the mobile device 121 magnifies or reduces the map.

A receive unit 122 of the mobile device receives display levels from a user (S605). For example, if a user inputs a "magnification" command while viewing a tenth- level map image shown FIG. 3 (b), an eleventh-level map image should be provided to the user. In such a case, the receive unit 122 receives information that a display level is a "level 11". Similarly, if a user inputs a "reduction" command while viewing a tenth- level map image shown in FIG. 3 (b), a ninth-level map image should be provided to the user. In such a case, the receive unit 122 receives information that a display level is a "level 9".

If the device receive unit receives the display level information, the device search unit 124 searches for a map data element associated with the display level among the map data elements stored in the device storage unit 123 (S606). A map image associated with the searched map data element is displayed on the device display unit 125 of the mobile device 121 (S607). According to an embodiment of the present invention, since the map data element is composed of the vector information, a map image that will be magnified or reduced can also be calculated based on the vector information. Even in this case, information on map data elements according to display levels, of course, depends on the display level information such as a level index.

In steps S605 to S607, a map data element in a different level that will be displayed on the device display unit 125 has been already received from the map information providing server 110 and stored in the device storage unit 123. Therefore, it is possible to sufficiently generate a desired map image only with the map data elements stored in the mobile device without the need to access the map information providing server 110 again so as to obtain the map data element in the different level. Consequently, according to the present embodiment of the present invention, since it is not necessary to download the map data element from the map information providing server whenever the user requests the map image in the different level, the map information in the different level can be rapidly provided to the user. Furthermore, since the map data elements common to the map information of the different levels are not redundantly sent from the map information providing server to the mobile device, data transfer efficiency can also be enhanced. FIG. 7 shows the map information database according to another embodiment of the present invention.

The map data elements in the map information database shown in FIG. 2 are classified into the polygon map data elements, the polyline map data elements and the POI information map data elements according to the respective elements, whereas map data elements shown in FIG. 7 are classified according to the display level information. That is, it is shown in FIG. 2 that information on which level is associated with the map data element is stored, whereas it is shown in FIG. 7 that information on what is the map data element belonging to each level is stored. FIG. 7 (a) shows a map information database in which ninth-level map data elements are stored, FIG. 7 (b) shows a map information database in which tenth-level map data elements are stored, and FIG. 7 (c) shows a map information database in which eleventh-level map data elements are stored.

The map data elements may be either image map information or vector map information.

As described above, according to the embodiment of the present embodiment, the map information database 111 causes the plurality of the map data elements associated with the display level information to be maintained according to the display level information.

Even in a case where a map data element desired by a user is the ninth-level map data element, the mobile device 121 send to the map information providing server 110 a request for the map information containing the position information associated with the map data element (information on a position where a map image associated with the map data element is displayed). In other words, the map information request is associated with the position information, which in turn corresponds to the information on the position associated with the map image that will be displayed on the mobile device 121.

The map information providing server 110 that received the map information request from the mobile device 121 searches for a map data element for each display level information, which is associated with the position information corresponding to the map information request. The device search unit 124 of the mobile device 121 searches for all the map data elements associated with a plurality of the display levels when the map data elements associated with the same position information are associated with the plurality of the display levels. In other words, even though a map data element a user immediately requires is the ninth-level map data element, the map information providing server 110 searches for the ninth- level, tenth-level and eleventh- level map data elements associated with the position information.

Next, the map information providing server 110 sends the searched map data elements to the mobile device 121. The transmit unit 115 of the map information providing server 110 sends the mobile device 121 all the map data elements associated with the plurality of the searched display levels. According to the embodiment of the present invention, even in a case where the user needs map data elements in different levels later on, the user does not have to download the map data elements again.

FIG. 8 is a conceptual view illustrating a process of maintaining map data elements and sending them to a mobile device according to a further embodiment of the present invention.

According to this embodiment, display level information is associated with group information each of which in turn is associated with a plurality of display level information. In other words, a plurality of display levels are bundled into a single group. As shown in FIG. 8, first, second, third and fourth display levels are grouped into a first group ("group 1"), fifth, sixth and seventh display levels are grouped into a second group ("group 2"), and eighth, ninth and tenth display levels are grouped into a third group ("group 3"). The group information may be stored in the map information database 111 in conjunction with the respective levels. Alternatively, the relationship between the levels and the relevant groups may be stored in an additional database. Reference numeral 807 designates a map data element stored in the map information providing server 111. Reference numerals 801, 803, 804, 805 and 806 designate individual map data elements, and reference numeral 802 designates display level information associated with the map data element 801. The map data element 801 corresponds to a map data element that is displayed in only the first and second levels. The map data element 803 corresponds to a map data element that is displayed in only the fifth and sixth levels. The map data element 804 corresponds to a map data element that is displayed in only the sixth and seventh levels. The map data element 805 corresponds to a map data element that is displayed in only the eighth and ninth levels. The map data element 806 corresponds to a map data element that is displayed in only the ninth and tenth levels.

The mobile device 121 sends a request for the map information including specific display level information and position information to the map information providing server 110. For example, it is assumed that the mobile device 121 requests a ninth-level map data element. The map information providing server 110 searches for group information to which the ninth-level element belongs. In this embodiment, a group to which the ninth-level element belongs is the third group. The search unit 114 of the map information providing server 110 searches for map data elements that belong to the third group and are associated with the position information. In this embodiment, it can be seen that map data elements associated with the eighth, ninth and tenth levels belonging to the third group are the map data elements 805 and 806. Therefore, the map information providing server 110 sends the map data elements 805 and 806 to the mobile device 121. Reference numeral 808 designates the map data elements 805 and 806 that are stored in the device storage unit 123 of the mobile device 121.

If a display level of the map data elements displayed on the device display unit of the mobile device 121 is a ninth level, the map data elements 805 and 806 will be displayed on the device display unit. Reference numeral 809 designates the map data elements 805 and 806 that are displayed on the device display unit of the mobile device 121. If a user inputs a "magnification" command to request a tenth-level map image, the map data element 806 associated with the tenth display level can be merely displayed on the device display unit without the need to request the download of an additional map data element to the map information providing server.

According to this embodiment, even in a case where the other level maps belonging to a specific group should be displayed, it is not necessary to further download map data elements. Furthermore, only the map data elements in a level close to a current display level are beforehand sent to the mobile device. Thus, it is possible to prevent unnecessary transmission of map data elements that will not be used. In addition, it is possible to prevent redundant transmission of the same map data elements for each level.

According to a still further embodiment of the present invention, there is provided a method of causing map images classified by respective levels to be stored beforehand in the map information providing server and then providing a specific level image map to the mobile device whenever a user requests the specific level image map through the mobile device. For example, if the mobile device requests a ninth-level map around Sinchon Station, the map information providing server provides the ninth- level map corresponding to the area. The mobile device displays the received ninth- level map. If the user wishes to magnify or reduce the current map on the mobile device, the mobile device is connected to the map information providing server to again request a new level map of the same area.

According to this embodiment, however, there is a problem in that the user should download new map information from the map information providing server whenever the user requests a different level map even though the map shows the same area. Although a map data element regarding "Yeonghwa Madang" is included in both tenth-level and eleventh-level maps, the map information on "Yeonghwa Madang" should be forwarded upon the transmission of the tenth-level map information. Further, the map information on "Yeonghwa Madang" will be redundantly transmitted again upon the later transmission of the eleventh-level map information. Such redundant transmission of the data results in increase of communication fees. Further, upon the request of the different level map information, the user should wait until the different level map information is downloaded. Thus, there is another problem in that the display of map information is delayed depending on the condition of the communication network. On the other hand, according to this embodiment, there is an advantage in that the map information in a level that the user does not view does not have to be forwarded.

According to a still further embodiment of the present invention, there is provided a method of transmitting basic image map information according to desired types and then displaying the image map information on the mobile device. This embodiment employs a method of transmitting information on an image map larger than a map region that the user wishes to view and displaying a part of the information about the large image map on the display unit of the mobile device when the user wishes to view a magnified or reduced map. According to this embodiment, there is a problem in that map data elements associated with only a specific level cannot be properly represented since the received image map is simply magnified or reduced. However, this embodiment has an advantage in that its implementation is simplified.

In addition, 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.

The computer system 900 includes at least one processor 901 that is connected to a main memory having a RAM 902 and a ROM 903. The processor 901 is also called a central processing unit (CPU). As well known in the art, the ROM 903 functions to transfer data and instructions unidirectionally to the CPU, and the RAM 902 is usually used to transfer data and instructions bi-directionally. The RAM 902 and the ROM 903 may include any types suitable for the computer-readable recording medium. A mass storage 904 is connected bi-directionally to the processor 901 and provides additional data storage capability. The mass storage 904 may be any one of the above computer- readable recording media. The mass storage 904 is used to store programs, data and the like and is generally an auxiliary storage device such as a hard disk having a data transfer rate slower than that of the main memory. A specific mass storage such as the CD ROM 906 may be employed. The processor 901 is connected to at least one I/O interface 905 such as a video monitor, a track ball, a mouse, a keyboard, a microphone, a touch screen display, a card reader, a magnetic or paper tape reader, a voice or handwriting recognizer, a joystick or other known computer I/O devices. Finally, the processor 901 may be connected to a wired or wireless communication network via a network interface 907. The above process can be performed through such network connection. These devices and tools are well known to those skilled in the field of computer hardware and software.

The hardware devices may be configured in the form of at least one software module for performing the operations of the present invention.

Industrial Applicability

According to the present invention, when map information is provided to a mobile device, an amount of data to be transmitted can be minimized by dividing a map corresponding to a single area into a plurality of levels and transmitting map information data common to the respective levels in a shared manner.

Further, according to the present invention, when a plurality of levels of map images are provided to a user, the map image corresponding to each level is not merely magnified or reduced but the information suitable to each level can be displayed. According to the present invention, when map information is provided to a mobile device, a map corresponding to a single area is divided into a plurality of levels and map data elements are maintained to correspond to the plurality of divided levels, whereby a map of a different level can be immediately displayed on the mobile device without any additional download in a case where the device intends to display the map of the different level after receiving the map information on the single area.

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.

Claims

1. A method for providing map information to a mobile device, comprising the steps of: (a) maintaining a map information database containing a plurality of map data elements each of which is associated with coordinate information and level information;

(b) receiving a request for map information from the mobile device;

(c) searching for the map data elements associated with position information corresponding to the map information request; and (d) transmitting the searched map data elements to the mobile device along with the display level information associated with the searched map data elements.

2. The method as claimed in claim 1, wherein the level information is information on whether the map data elements are displayed when a map of a specific level is displayed on a display means of the mobile device.

3. The method as claimed in claim 2, wherein the display level information contain information on a plurality of levels associated with the map data elements.

4. The method as claimed in claim 2, wherein when a plurality of maps for the same place is displayed on the display means of the mobile device, the level information includes identifiers which are associated with the plurality of displayed maps.

5. The method as claimed in claim 1, wherein the level information is associated with group information each of which in turn is associated with a plurality of the level information.

6. The method as claimed in claim 5, wherein the map information request received from the mobile device contains the group information, and step (c) comprises the step of searching for the position information corresponding to the map information request and the map data elements associated with the group information.

7. The method as claimed in claim 5, wherein the map information request received from the mobile device contains the level information, and step (c) comprises the steps of searching for the group information associated with the level information contained in the map information request and searching for the position information corresponding to the map information request and the map data elements associated with the group information.

8. The method as claimed in claim 1, wherein the map data element includes a polygon, a polyline and POI information.

9. The method as claimed in claim 8, wherein when the map data element is the polygon or polyline, the coordinate information associated with the map data element is at least one vertex coordinate of the polygon or polyline.

10. The method as claimed in claim 8, further comprising the steps of:

(e) maintaining icons associated with the POI information; and

(f) transmitting the icons associated with the POI information to the mobile device.

11. The method as claimed in claim 10, wherein step (f) comprises the step of transmitting all the icons associated with the POI information to the mobile device when the mobile device is connected to a predetermined map information providing server.

12. A method for providing map information in a mobile device, comprising the steps of: requesting a predetermined map information providing server to forward map information that is associated with position information; receiving map data elements associated with the position information from the map information providing server, wherein each of the map data elements is associated with coordinate information and level information; storing the received map data elements; determining a display level of a map image to be displayed on a display means of the mobile device; searching for map data elements associated with the determined display level among the stored map data elements; and displaying a map image associated with the searched map data elements on the display means of the mobile device.

13. The method as claimed in claim 12, further comprising the steps of: receiving the display level information from a user; searching for map data elements associated with the display level information among the stored map data elements in response to the reception of the display level information; and displaying a map image associated with the searched map data elements on the display means of the mobile device.

14. A method for providing map information to a mobile device, comprising the steps of: maintaining a plurality of map data elements associated with display level information in a map information database according to the display level information; receiving a request for map information from the mobile device; searching for the map data elements by the display level information associated with position information corresponding to the map information request; and transmitting the searched map data elements by the display level information to the mobile device.

15. The method as claimed in claim 14, wherein the map information request received from the mobile device is associated with the position information which in turn is associated with a map image to be displayed on the mobile device.

16. The method as claimed in claim 14, wherein the display level information is associated with group information each of which is in turn associated with a plurality of the display level information.

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

18. A system for providing map information to a mobile device, comprising: a map information database for storing a plurality of map data elements each of which is associated with coordinate information and level information; a receive unit for receiving a request for map information including position information from the mobile device; a search unit for searching the map information database for the map data elements associated with the position information in response to the map information request; and a transmit unit for transmitting the searched map data elements to the mobile device along with the level information associated with the searched map data elements.

19. The system as claimed in claim 18, further comprising an icon database for storing icons associated with POI information and icon identifiers that identify the icons.

20. The system as claimed in claim 18, wherein the mobile device comprises: a device input unit for receiving the transmitted map data elements from the map information providing system; a device storage unit for storing the received map data elements; a device search unit for searching for map data elements associated with display level information among the stored map data elements; and a device display unit for displaying a map image associated with the searched map data elements on the mobile device.

21. A system for providing map information to a mobile device, comprising: a map information database for maintaining a plurality of map data elements according to display levels, said map data element being associated with the display levels; a receive unit for receiving a request for map information including position information from the mobile device; a search unit for searching the map information database for the map data elements associated with the position information in response to the map information request; and a transmit unit for transmitting the searched map data elements to the mobile device along with the level information associated with the searched map data elements.

22. The system as claimed in claim 21, wherein the search unit searches for all the map data elements associated with a plurality of the display levels if map data elements associated with the same position information are associated with the plurality of the display levels, and the transmit unit transmits all the map data elements associated with the plurality of the searched display levels to the mobile device.