Abstract:
Provided is a technology of a navigation device which is capable of identifying an intersection or the like based on designation of an incomplete name of a street in which an input of a first keyword and an input of a second keyword are received, and a connection point of a first street having a street name which includes at least in part the first keyword and a second street having a street name which includes at least in part the second keyword is identified, to thereby save the user, who is not always familiar with the geography of a search target area, from the inconvenience of inputting a complete name of the first street, based on which the second street is retrieved and selected and an intersection point of the first street and the second street is identified.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a technology for a navigation device. 
         [0002]    Conventionally, there has been provided a technology for a navigation device in which an input of a name of a first street is received, and one of second streets retrieved based on the name thus received is selected and input, to thereby identify data (such as a branch point or a branch area) to be retrieved. 
         [0003]    A technology for a navigation device as described above is disclosed in Japanese Patent Laid-open Publication No. 2008-76359. 
         [0004]    However, in the navigation device described above, a complete name needs to be input as the name of a street. The street may not be identified when the name is incomplete. 
         [0005]    In general, there are many cases where an operator of the navigation device is not familiar with the geography of the area to be searched, and therefore it is rare that the operator is capable of designating the complete name of the street. In other words, the operator may find the above-mentioned navigation device inconvenient. 
       SUMMARY OF THE INVENTION 
       [0006]    It is an object of the present invention to provide a technology of a navigation device capable of identifying an intersection or the like based on designation of an incomplete name of a street. 
         [0007]    In order to solve the above-mentioned problem, the present invention provides a navigation device including: storage unit adapted to store, for each, street, information for associating a name of the street, streets connecting to the street, and points of the connections; first input receiving unit adapted to receive an input of a first keyword forming a part of the name of the street; second input receiving unit adapted to receive an input of a second keyword forming another part of the name of the street; first identifying unit adapted to identify, as a first street, a street having a street name including the first keyword; second identifying unit adapted to identify, as a second street, a street having a street name including the second keyword; and connection point identifying unit adapted to identify a point at which the first street and the second street are connected to each other. 
         [0008]    Further, the present invention provides a navigation method for a navigation device, the navigation device including storage unit adapted to store, for each street, information for associating a name of the street, streets connecting to the street, and points of the connections, the navigation method including: a first receiving step of receiving an input of a first keyword forming a part of the name of the street; a second receiving step of receiving an input of a second keyword forming another part of the name of the street; a step of identifying, as a first street, a street having a street name including the first keyword; a step of identifying, as a second street, a street having a street name including the second keyword; and a connection point identifying step of identifying a point at which the first street and the second street are connected to each other. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    In the accompanying drawings: 
           [0010]      FIG. 1  is a schematic configuration diagram illustrating a navigation device to which an embodiment of the present invention is applied; 
           [0011]      FIG. 2  illustrates a configuration example of a link table; 
           [0012]      FIG. 3  illustrates a configuration example of a street information table; 
           [0013]      FIG. 4  illustrates a functional configuration of a processing unit; 
           [0014]      FIG. 5  is a flow chart of a connection point guiding processing; 
           [0015]      FIGS. 6A to 6C  each illustrate a screen example employed in the connection point guiding processing; 
           [0016]      FIGS. 7A and 7B  each illustrate a specific example of processing performed in the connection point guiding processing; and 
           [0017]      FIG. 8  illustrates a modified flow of the connection point guiding processing. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0018]    In the following, a navigation device  100  to which an embodiment of the present invention is applied is described with reference to the accompanying drawings. 
         [0019]      FIG. 1  is a schematic configuration diagram of a vehicle navigation device  100  to which the present invention is applied. As illustrated in  FIG. 1 , the vehicle navigation device  100  includes a processing unit  1 , a display  2 , a storage unit  3 , a voice input/output unit  4  (including a microphone  41  as a voice input unit and a speaker  42  as a voice output unit), an input unit  5 , a ROM device  6 , a vehicle speed sensor  7 , a gyro sensor  8 , a global positioning system (GPS) receiver  9 , an FM multiplex broadcasting receiver  10 , and a beacon receiver  11 . 
         [0020]    The processing unit  1  is a central unit which performs various kinds of processing. For example, the processing unit  1  detects the present location based on information output by, for example, the various sensors  7  and  8 , the GPS receiver  9 , the FM multiplex broadcasting receiver  10 , and the beacon receiver  11 . Further, based on the obtained information on the present location, the processing unit  1  reads out map data necessary for display, from the storage unit  3  or the ROM device  6 . Still further, the processing unit  1  graphically develops the map data thus read out, and displays the map data thus developed with a mark indicating the present location superposed thereon, on the display  2 . Alternatively, the processing unit  1  makes a search for an optimal route (recommended route) which connects a departure place (present location) to a destination which are designated by the user, by using the map data or the like stored in the storage unit  3  or the ROM device  6 . In addition, the processing unit  1  provides the user with guidance by using the speaker  42  and the display  2 . 
         [0021]    The processing unit  1  is implemented by connecting various devices through a bus  25 . The processing unit  1  includes: a central processing unit (CPU)  21  which executes various kinds of processing such as performing mathematical operations and control on each of the devices; a random access memory (RAM)  22  which stores map data and operation data read out from the storage unit  3 ; a read only memory (ROM)  23  which stores programs and data, and an interface (I/F)  24  which connects various kinds of hardware to the processing unit  1 . 
         [0022]    The display  2  is a unit which displays graphic information created in the processing unit  1 . The display  2  includes, for example, a liquid crystal display, or an organic electroluminescence (EL) display. 
         [0023]    The storage unit  3  includes a storage medium such as a hard disk drive (HDD) or a nonvolatile memory card, which is capable of at least reading and writing. 
         [0024]    The storage medium stores a link table  200  and a street information table  300 , as map data (including link data on links constituting roads on the map) necessary for a general route search device. 
         [0025]      FIG. 2  illustrates a configuration example of the link table  200 . The link table  200  contains, for each identification code (mesh ID)  201  for a mesh which is a partitioned area on a map, link data  202  on each of the links constituting roads included in the mesh area. 
         [0026]    The link data  202  contains, for each link ID  211  which is an identifier of the link, coordinate information  222  on two nodes (initiating node and terminating node) which form the link, a road type  223  indicating a type of the road which includes the link, a link length  224  and a link travel time  225  which indicate a distance of the link, an initiating connection link and terminating connection link  226  which contain link IDs (connection link IDs) of links connecting to the two nodes forming the link, and a popular name  227  indicating a popular name (such as “MAIN”) of the road which includes the link. 
         [0027]    It should be noted that, in this example, the two nodes forming the link are differentiated from each other as the initiating node and the terminating node, and hence the upbound direction and the downbound direction of the same road are separately managed as different links. The link travel time  225  may include link travel times which are associated with conditions such as date and weather. 
         [0028]      FIG. 3  illustrates a configuration example of the street information table  300 . The street information table  300  stores, for each street indicating a road, a connecting street which connects to the street and a connection point (such as intersection or roundabout) at which the street connects to the connecting street, such that the connecting street and the connection point are associated with each other. 
         [0029]    The street information table  300  stores a street ID  301  which identifies the street and a street name  302  which includes the name of the street, such that the street ID  301  and the street name  302  are associated with each other. The street information table  300  contains, for each street ID  301 , a connecting street ID  311  which identifies a connecting street, and an intersection node ID  312  which identifies a connection point at which the street connects to the connecting street. 
         [0030]    Specifically, the street ID  301  includes information for identifying the street, such as “00001” and “00002”. 
         [0031]    The street name  302  includes information related to a name of the street identified by the street ID  301 . For example, names such as “MAIN” and “EASTMAIN” are included. 
         [0032]    It should be noted that the street name  302  is stored as being associated with the street ID  301 . When the street has another name, the street ID  301  may be associated with a plurality of street names. 
         [0033]    The connecting street ID  311  includes information for identifying a connecting street which connects to the street identified by the street ID  301  (The connection includes intersection at an intersection or connection at a roundabout). 
         [0034]    In a case where a plurality of connecting streets connect to one street, the connecting street IDs  311  to be associated with the plurality of connecting streets are provided as many, as the number of the plurality of streets. 
         [0035]    The intersection node ID  312  includes information for identifying a point (node) at which a street identified by the street ID  301  and a street identified by the connecting street ID  311  connect to each other. 
         [0036]    Referring again to  FIG. 1 , the navigation device  100  is further described. The voice input/output unit  4  includes the microphone  41  as a voice input unit and the speaker  42  as a voice output unit. The microphone  41  picks up a sound produced outside the vehicle navigation device  100 , such as a voice uttered by the user or another passenger. 
         [0037]    The speaker  42  outputs a message to the user, which is created in the processing unit  1 , as a voice signal. The microphone  41  and the speaker  42  are separately disposed at predetermined positions in a vehicle, or may be integrally accommodated in a casing. The vehicle navigation device  100  may include a plurality of the microphones  41  and a plurality of the speakers  42 . 
         [0038]    The input unit  5  receives an instruction from the user, through operations performed by the user. The input unit  5  includes a touch panel  51 , a dial switch  52 , a scroll key, a scale adjusting key as other hard switches (not shown), and the like. 
         [0039]    The touch panel  51  is mounted on a display surface side of the display  2 , allowing the display screen to be seen therethrough. The touch panel  51  identifies a touch position which is associated with the X and Y coordinates of an image displayed on the display  2 , and outputs the touch position converted into a form of the coordinates. The touch panel  51  includes a pressure-sensitive or electrostatic input detecting element or the like. 
         [0040]    The dial switch  52  is configured to be rotatable in a clockwise direction or in a counter-clockwise direction, generates a pulse signal for each predetermined angle of rotation, and outputs the pulse signal to the processing unit  1 . The processing unit  1  obtains the rotational angle based on the number of the pulse signals. 
         [0041]    The ROM device  6  includes a storage medium such as a read only memory (ROM) including CD-ROM and DVD, or an integrated circuit (IC) card, which is at least readable. The storage medium stores, for example, moving image data and voice data. 
         [0042]    The vehicle speed sensor  7 , the gyro sensor  8 , and the GPS receiver  9  are used for detecting a present location (own vehicle position) by the vehicle navigation device  100 . 
         [0043]    The vehicle speed sensor  7  outputs a value to be used for calculating a vehicle speed. The gyro sensor  8  includes an optical-fiber gyroscope or a vibrating gyroscope, and detects an angular speed according to the rotation of a moving object. The GPS receiver  9  receives a signal from a GPS satellite and measures, with respect to at least three GPS satellites, a distance between a moving object and each of the GPS satellites and a rate of change in the distance, to thereby obtain a present location, a traveling speed, and a traveling direction of the moving object, which are transmitted to the processing unit  1 . 
         [0044]    The FM multiplex broadcasting receiver  10  receives an FM multiplex broadcasting signal transmitted from an FM multiplex broadcasting station. The FM multiplex broadcasting includes general current traffic information, regulation information, service area/parking area (SA/PA) information, parking information, weather information, which are provided as vehicle information communication system (VICS: registered trademark) information, and text information provided as FM multiplex general information by a radio station. 
         [0045]    The beacon receiver  11  receives a signal such as an optical beacon or a radio wave beacon. The signal such as a beacon includes general current traffic information, regulation information, service area/parking area (SA/PA) information, and parking information, which are provided as VICS information. 
         [0046]      FIG. 4  is a functional block diagram of the processing unit  1 . 
         [0047]    As illustrated in  FIG. 4 , the processing unit  1  includes a main control unit  101 , an input reception unit  102 , an output processing unit  103 , a voice input reception unit  104 , a connection point identification unit  105 , a route search unit  106 , and a route guidance unit  107 . 
         [0048]    The main control unit  101  is a central functional unit which performs various kinds of processing, and controls other processing units depending on the type of the processing. Further, the main control unit  101  performs navigation processing (for example, display of traffic information, or display of a present location) which is a basic operation of the vehicle navigation device  100 . 
         [0049]    The input reception unit  102  is a processing unit which receives an instruction input by, the user through the touch panel  51  and the dial switch  52 , and passes the instruction to each of the processing units. 
         [0050]    The output processing unit  103  is a functional unit which causes the display  2  to perform a screen output. The output processing unit  103  receives screen data and display candidates which are required to be displayed on the display  2 , and creates a screen drawing command so that a road and other elements constituting the map, a present location, a destination, a recommended route, and a dialogue for message information are rendered by a designated drawing method. Then, the created command is transmitted to the display  2 . 
         [0051]    The voice input reception unit  104  is a processing unit which receives an instruction input by the user through the microphone  41 , and passes the instruction to each of the processing units. 
         [0052]    The connection point identification unit  105  receives input information designating a first street, and receives input information designating a second street, to thereby identify an intersection node at which the first street and the second street connect to each other. 
         [0053]    The route search unit  106  retrieves a route minimal in cost (for example, in terms of distance or travel time) which connects designated two points (present location and destination or stop-off point), by using Dijkstra&#39;s algorithm or the like. It should be noted that the route is defined by sequentially connecting in series a plurality of nodes which are points provided at positions indicating a road and links connecting two nodes. Further, the route search unit  106  combines costs given in advance with respect to each node and each link included in the route, to thereby determine the cost for the entire route. Then, the route search unit  106  calculates a time that it takes to reach the destination or the stop-off point through the route, and stores route information for specifying the route, in a predetermined area of the RAM  22  or the storage unit  3 . 
         [0054]    The route guidance unit  107  identifies the route based on the route information corresponding to the route obtained as a result of the search performed by the route search unit  106 , and provides the user with guidance on the travel route. 
         [0055]    For example, the route guidance unit  107  compares the route information and information on the present location, and informs the user whether or not to go straight or to turn left or right before passing through an intersection or the like, by voice with the use of the speaker  42 . 
         [0056]    Still further, the route guidance unit  107  displays a traveling direction on a map displayed on the display  2 , to thereby inform the user of a recommended route. 
         [0057]    It should be noted that the CPU  21  executes programs loaded in the RAM  22  or the ROM  23 , to thereby implement the main control unit  101 , the input reception unit  102 , the output processing unit  103 , the voice input reception unit  104 , the connection point identification unit  105 , the route search unit  106 , and the route guidance unit  107 . 
         [0058]    [Description of Operations] Next, an operation of the vehicle navigation device  100  with the above-mentioned configuration is described. 
         [0059]      FIG. 5  is a flow chart for illustrating a flow of connection point guiding processing. 
         [0060]    The main control unit  101  receives an instruction from the user of the navigation device  100 , and starts the flow of the processing. 
         [0061]    The input reception unit  102  receives an input of a keyword for specifying the first street (Step S 001 ). 
         [0062]    Specifically, the input reception unit  102  receives designation of a keyword included in the name of the street. At this time, the input reception unit  102  receives a keyword corresponding to a part or all of the name of the street. There is no need for the user to designate the correct name of the street. 
         [0063]    When receiving the keyword designation, the input reception unit  102  receives the input in units of written characters such as alphabets. 
         [0064]    In order to receive an input by voice, the voice input reception unit  104  receives designation of, a keyword included in the name of the street. In this case, the voice input reception unit  104  receives a voice for specifying the keyword as an utterance expression of a word or the like. However, the present invention is not limited thereto, and the voice input reception unit  104  may receive a voice expressing a word consisting of a group of alphabets pronounced one by one. 
         [0065]    Next, the connection point identification unit  105  identifies candidate streets for the first street, and determines the street IDs of the candidate streets (Step S 002 ). 
         [0066]    Specifically, the connection point identification unit  105  identifies, in the street information table  300 , a street including the keyword received in Step S 001  as the street name  302 , and reads out the street ID  301  of the street. 
         [0067]    At this time, in a case where there are a plurality of streets which include the keyword, the connection point identification unit  105  identifies, in the street information table  300 , all the streets including the keyword, and reads out all the street IDs  301  of the streets thus identified. 
         [0068]    Next, the input reception unit  102  receives an input of a keyword for specifying the second street (Step S 003 ). 
         [0069]    Specifically, the input reception unit  102  receives designation of a keyword included in the name of the street. At this time, the input reception unit  102  receives a keyword corresponding to a part or all of the name of the street. There is no need for the user to designate the correct name of the street. 
         [0070]    When receiving the keyword designation, the input reception unit  102  receives the input in units of written characters such as alphabets. 
         [0071]    In order to receive an input by voice, the voice input reception unit  104  receives designation of a keyword included in the name of the street. In this case, the voice input reception, unit  104  receives a voice for specifying the keyword as an utterance expression of a word or the like. However, the present invention is not limited thereto, and the voice input reception unit  104  may receive a voice expressing a word consisting of a group of alphabets pronounced one by one. 
         [0072]    Next, the connection point identification unit  105  identifies candidate streets for the second street, and determines the street IDs of the candidate streets (Step S 004 ). 
         [0073]    Specifically, the connection point identification unit  105  identifies, in the street information table  300 , a street including the keyword received in Step S 003  as the street name  302 , and reads out the street ID  301  of the street. 
         [0074]    At this time, in a case where there are a plurality of streets which include the keyword, the connection point identification unit  105  identifies, in the street information table  300 , all the streets including the keyword, and reads out all the street IDs  301  of the streets thus identified. 
         [0075]    Next, the connection point identification unit  105  identifies a present location of a vehicle on which the navigation device  100  is mounted, and sets streets included in a state to, which the present location belongs, as search targets (S 005 ). 
         [0076]    Specifically, the connection point identification unit  105  requests coordinates specifying the present location, from the main control unit  101 , and identifies an administrative area (for example, state) which includes a position specified by the coordinates. 
         [0077]    Then, the connection point identification unit  105  identifies a street which is included in part in the identified administrative area, and extracts, as a search target, the corresponding street from the street information table  300 . 
         [0078]    It should be noted that the search targets may not be limited to streets included in the administrative area, and streets in the vicinity of the present location may be included as eh search targets. Specifically, the search targets may include a street which is included in part within a predetermined distance from the present location. Alternatively, the search targets may include a street which includes in part a link directly connecting to a node in a mesh to which the present location belongs. 
         [0079]    Next, from among intersection nodes belonging to a street which matches any one of the first street IDs determined in Step S 002 , the connection point identification unit  105  identifies an ID of an intersection node indicating a connection point at which the first street connects to a street which matches any one of the second street IDs (Step S 006 ). 
         [0080]    Specifically, the connection point identification unit  105  identifies, from among, the search targets set in Step S 005 , records which includes the street ID  301  matching any one of the first street IDs determined in Step S 002 . Then, the connection point identification unit  105  further identifies, from among the identified records, a record which includes the connecting street ID  311  matching any one of the second street IDs determined in Step S 004 , and identifies the intersection node ID  312  of the record. 
         [0081]    Next, the output processing unit  103  displays on the display  2  the list of the intersection node IDs  312  identified in Step S 006  (Step S 007 ). 
         [0082]    Specifically, the output processing unit  103  displays first street names in association with second street names, the first street names and the second street names constituting the intersection node IDs  312  identified in Step S 006 , to thereby display the list of information for specifying the intersection node IDs  312 . 
         [0083]    Next, the input reception unit  102  receives designation of one intersection node ID, from among the list of the intersection node IDs  312  displayed in Step S 007  (Step S 008 ). 
         [0084]    Specifically, the input reception unit  102  receives an input of designation for identifying a combination of the first street name and the second street name in the list of information displayed in Step S 007 . 
         [0085]    Next, the route search unit  106  retrieves a route from the present location of the vehicle on which the navigation device  100  is mounted to the intersection node for which an input of designation is received in Step S 008  (Step S 009 ). 
         [0086]    Next, the route guidance unit  107  starts providing guidance on the route retrieved in Step S 009  (Step S 010 ). 
         [0087]    Hereinabove, the flow of the connection point guiding processing has been described. 
         [0088]    Next, an example of a screen display displayed in the connection point guiding processing is described with reference to  FIGS. 6A to 6C . 
         [0089]      FIG. 6A  illustrates an example of a screen display displayed in Step S 001  of the connection point guiding processing (in a case of voice input). 
         [0090]      FIG. 6A  illustrates a screen  400  and a message display area  401  displayed within the screen  400 . The message display area  401  displays a message requesting an input of a keyword for specifying a first street name, such as “PLEASE SAY A KEYWORD FOR THE FIRST STREET NAME.”. 
         [0091]    After the processing in Step S 002  is completed, the screen  400  makes a transition to a screen  410  coming next. 
         [0092]      FIG. 6B  illustrates an example of a screen display displayed in Step S 003  of the connection point guiding processing (in the case of voice input). 
         [0093]      FIG. 6B  illustrates the screen  410  and a message display area  411  displayed within the screen  410 . The message display area  411  displays a message requesting an input of a keyword for specifying a second street name, such as “PLEASE SAY A KEYWORD FOR THE SECOND STREET NAME.”. 
         [0094]    After the processing in Step S 006  is completed, the screen  410  makes a transition to a screen  420  coming next. 
         [0095]      FIG. 6C  illustrates an example of a screen display displayed in Step S 007  of the connection point guiding processing. 
         [0096]      FIG. 6C  illustrates the screen  420 , a message display area  421  displayed within the screen  420 , and a connection point list display area  422 . 
         [0097]    The message display area  421  displays a message requesting an input for selecting an intersection node, such as “THERE ARE A PLURALITY OF CONNECTION POINTS AS CANDIDATES. PLEASE SELECT ONE OF THE CONNECTION POINTS.”. 
         [0098]    The connection point list display area  422  displays a list of combinations of the first street names and the second street names, which is information for identifying the connection points. 
         [0099]    After the processing in Step S 008  is completed, the screen  420  makes a transition to a screen for providing route guidance. 
         [0100]    Next, a specific example of the connection point guiding processing is described with reference to  FIGS. 7A and 7B . 
         [0101]      FIG. 7A  schematically illustrates an example of roads included in an area to be subjected to the connection point guiding processing.  FIG. 7A  illustrates a positional relation among a connection point  510  at which a “MAIN” street  501  connects to a “WESTFIRST” street  502 , a connection point  511  at which the “MAIN” street  501  connects to a “HARBOR” street  503 , a connection point  512  on the west side and a connection point  513  on the east side at each of which the “MAIN” street  501  connects to an “EASTFIRST” street  504 , a connection point  514  at which a “MAINTAIN” street  505  connects to the “WESTFIRST” street  502 , and a connection point  515  at which the “MAINTAIN” street  505  connects to the “HARBOR” street  503 . 
         [0102]    In this example, when a keyword is designated as “MAIN” in Step S 001  of the connection point guiding processing, streets with a name including a keyword “MAIN”, namely, the “MAIN” street  501  and the “MAINTAIN” street  505 , are determined as candidate streets in Step S 002 . 
         [0103]    Further, when a keyword is designated as “FIRST” in Step S 003 , streets with a name including a keyword “FIRST”, namely, the “WESTFIRST” street  502  and the “EASTFIRST” street  504 , are determined as candidate streets in Step S 004 . 
         [0104]    In this case, in Step S 006 , the connection point identification unit  105  identifies, as the intersection nodes, the connection point  510  of the “MAIN” street  501  and the “WESTFIRST” street  502 , the connection point  512  on the west side and the connection point  513  on the east side of the “MAIN” street  501  and the “EASTFIRST” street  504 , and the connection point  514  of the “MAINTAIN” street  505  and the “WESTFIRST” street  502 . 
         [0105]    Then, in Step S 007 , the output processing unit  103  displays a list of records which includes the connection point  510  of the “MAIN” street  501  and the “WESTFIRST” street  502  as a first record, the connection point  512  on the west side of the “MAIN” street  501  and the “EASTFIRST” street  504  as a second record, the connection point  513  on the east side of the “MAIN” street  501  and the “EASTFIRST” street  504  as a third record, and the connection point  514  of the “MAINTAIN” street  505  and the “WESTFIRST” street  502  as a fourth record. 
         [0106]    Hereinabove, the embodiment of the present invention has been described. 
         [0107]    According to the above-mentioned embodiment of the present invention, the vehicle navigation device  100  is capable of identifying streets based on keywords for names of the streets, and identifying an intersection or the like at which the two streets thus identified connect to each other, to thereby provide route guidance. The above-mentioned embodiment may be implemented as an effective destination identification method of setting a destination based only on a keyword, even in unfamiliar places, for example, in an area where an address is identified mainly based on a street name. 
         [0108]    The present invention is not limited to the above-mentioned embodiment. The above-mentioned embodiment may be subjected to various modifications within the scope of the technical idea of the present invention. 
         [0109]    For example, in the above-mentioned embodiment, the flow of the connection point guiding processing proceeds from Step S 001  to Step  5010  in sequence as described above. However, the present invention is not limited thereto. 
         [0110]    That is, an input of a keyword for the first street is received and an input of a keyword for the second street is received, and then a street ID for the first street candidate may be determined and a street ID for the second street candidate may be determined. 
         [0111]    Alternatively, the search targets may be set prior to Step S 001  and then Step S 001  may be performed, rather than setting the search targets in Step S 005 . 
         [0112]    Further, in the above-mentioned embodiment, in the connection point guiding processing, the intersection nodes are identified in Step S 006  and then the list of all the identified intersection nodes is displayed in Step S 007 . However, the present invention is not limited thereto. 
         [0113]    That is, in a case where the number of intersection nodes identified in Step S 006  exceeds a predetermined number (for example, fifty), the number may be reduced through search refinement by additionally providing a search keyword or by narrowing down a search target area (for example, to a city). 
         [0114]    Specifically, processing illustrated in  FIG. 8  may be performed. 
         [0115]      FIG. 8  illustrates a modified flow of the connection point guiding processing. 
         [0116]    As illustrated in  FIG. 8 , between Step S 006  and Step S 007 , the connection point identification unit  105  judges whether the number of identified intersection nodes is equal to or smaller than a predetermined number (Step S 021 ). In a case where the number of intersection nodes is not equal to or smaller than the predetermined number (in a case of “No” in Step S 021 ), the number of intersection nodes is reduced through the search refinement as described above, and the control is returned to Step  5021  (Step  5022 ). When the number of intersection nodes is equal to or smaller than the predetermined number (in a case of “Yes” in Step S 021 ), the control is passed to Step S 007 . 
         [0117]    The connection point guiding processing may be modified as described above. When the processing is modified as described above, in the navigation device  100 , there may be avoided a case where so many intersection nodes are displayed that the user is unable to make designation. 
         [0118]    Further, in the connection point guiding processing, when displaying the list of intersection node IDs  312  identified in Step  5006  on the display  2  in Step S 007 , names of the intersection indicating the intersection nodes may also be displayed. 
         [0119]    With this configuration, the user may receive more information for recognizing the intersection nodes, and hence the designation of the intersection node may be made with ease. 
         [0120]    In the above-mentioned embodiment, the description is given of the example in which the present invention is applied to the vehicle navigation device. However, the present invention may also be applied to a navigation device used for any other purpose than vehicle.