Road guide method and device

Description: TECHNICAL FIELD [Detailed description of the invention]

【0001】

[Technical field to which the invention belongs]

The present invention mainly relates to a route guidance method and device for providing route guidance to pedestrians by presenting a guide text or a simplified map.

【0002】

[Conventional technology]

Devices have been developed that mainly provide pedestrians with directions to their destinations by presenting directions and simplified maps. Such a route guidance device is configured as a single portable device, or is mounted on a mobile communication terminal such as a mobile phone.

【0003】

Conventional route guidance technology includes, for example, the credential technique PRU95-215 "Interactive route generation in a map image generation system and its application to map generation", Horie, Kimura, Babaguchi et al. (Reference 1), or the credible technique. PRU95-156 "Modeling of map road structure and generation of rough map and guide text based on it", Kimura, Babaguchi, Kitahashi et al. (Reference 2), guide by simple map and guide text The technology to do is known.

【0004】

Regarding the generation of directions, in Reference 1, it is possible to present sentences such as "Go west for 20 m" and "Turn right at the intersection" as guides. However, it is difficult for some pedestrians to get a sense of distance, especially for a numerical value such as ** m, and since there are innumerable intersections, especially in urban areas, it is different from the intersection specified in the directions. You may misidentify an intersection. Therefore, such a route guide sentence is not always sufficiently easy to understand for pedestrians. Reference 2 only presents directions such as "roads merge" and "go on a branch to **", which is even more difficult to understand than the directions presented in Reference 1. It has become a thing.

【0005】

[Problems to be Solved by the Invention]

As described above, in the conventional route guidance technology, the presentation of the route guide text is not always an easy-to-understand explanation for pedestrians, and the intersection, confluence, branch point, etc. indicated by the route guide text may be misunderstood. There was a possibility of doing.

【0006】

The present invention is to provide a route guidance method and device capable of providing a more understandable route guide to a pedestrian.

【0007】

[Means for solving problems]

In order to solve the above problems, in the present invention, in order to provide route guidance based on map data including road network data and landmark data, a route from a departure point to a destination specified by a user is provided from the road network data. After searching, the road shape in the route searched based on the road network data, for example, the shape of an intersection or a rotary is analyzed to generate road shape data, and the road shape data and the landmark data are used for the search. Generates route guidance information corresponding to the route. When analyzing an intersection shape as a road shape, at least the number of roads connected to the intersection and the angle of the roads are obtained.

【0008】

In the generation of route guidance information, for example, landmark data of landmarks along the route is selected based on the road shape data, and a route guide text including a description of the road shape and the landmark name is generated as the route guidance information. Then, this landmark will be presented by at least one of the character string and the voice. In the generation of other route guidance information, a simplified map along the searched route is generated based on the road network data, the road shape data, and the landmark data, and this simplified map is presented as an image.

【0009】

It has a database that stores presentation patterns corresponding to each of a plurality of road shapes, and the presentation patterns corresponding to the road shapes indicated by the road shape data analyzed in the generation of the route guidance information are selected from the database. The presentation pattern may be combined as route guidance information. In this case, the presentation pattern may be used as bit map data, and by synthesizing these bit map data, a simplified map along the route may be generated as route guidance information, or vector data may be stored as the presentation pattern, and these may be stored. By connecting the vector data of, a simplified map along the route may be generated as route guidance information.

【0010】

Further, according to the present invention, it is a program for causing a computer to execute a process of performing route guidance based on map data including road network data and landmark data, and the purpose is from the departure point specified by the user from the road network data. Processing to search for a route to the ground, processing to obtain road shape data by analyzing the road shape in the route based on road network data, and route guidance information corresponding to the route using road shape data and landmark data A program is provided for causing a computer to execute a process of generating data and a process of presenting route guidance information.

【0011】

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing a configuration of a route guidance device according to an embodiment of the present invention. Database 1 stores basic data for generating a simplified map along a route and a route guide, such as a map data, a route guide database used for generating a route guide, and a simplified map database.

【0012】

The map data includes road network data and landmark data in addition to the map image. The route guide database and the simplified map database may include a presentation pattern corresponding to the road shape. Further, the simplified map database may store the presentation pattern corresponding to the road shape as bitmap data or as vector data.

【0013】

The database 1 may be provided in the route guidance device, but when the function of the route guidance device is implemented in a mobile communication terminal such as a mobile phone, or the route guidance device is configured as a dedicated portable device. In this case, it is provided outside the route guidance device and is connected to the route guidance device by a wireless communication path. In addition, the map data and landmark data of the database 1 are used as an external database provided outside the route guidance device, and the remaining route guide text database and simplified map database are configured as an internal database to be configured inside the route guidance device. You may.

【0014】

The user input unit 2 is for a user who uses the route guidance device, that is, a pedestrian, to perform various input operations by key operation, dial operation, or the like. When the user inputs the position information of the departure place and the destination by the user input unit 2, the road network data is read from the database 1 based on the position information and passed to the route search unit 3.

【0015】

In the route search unit 3, the departure point to the destination is based on the position information of the departure place and the destination input by the user input unit 2 and the road network data read from the database 1 corresponding to the position information. The route to is searched, and route data representing this route as, for example, vector data is generated.

【0016】

The road shape analysis unit 4 analyzes (pattern analysis) the road shape in the route indicated by the route data by referring to the road network data in the database 1 corresponding to the route data from the route search unit 3. Road shape data is generated. Here, the road shape is the shape of the road included in the route and further included in the vicinity of the route, and as will be described in detail later, the road is a straight road, an intersection or a corner (crank, S-shaped curve, etc.). ) Or the type (road attribute) such as in front of the station, but if it is an intersection or a corner, it is information indicating what the shape is. The specific analysis method of this road shape will be described in detail later.

【0017】

The route guidance text generation unit 5 and the simplified map generation unit 6 use at least the road shape data from the road shape analysis unit 4 and the landmark data read from the database 1 corresponding to the road shape data, and further, the database 1 The route guidance text and simplified map data are used as the route guidance information for guiding the user along the route indicated by the route data from the route search unit 3 using the route guide text database and the simplified map database. Is generated.

【0018】

The presentation unit 7 includes a display or a display and a speaker. In this presentation unit 7, the route guide text is displayed by a character string, voice, or both based on the route guide text data from the route guide text generation unit 5, and further, the departure is based on the simplified map data from the simplified map generation unit 6. By displaying the simplified map along the route from the place to the destination as an image, these directions and the simplified map are presented to the user.

【0019】

Among the components of the route guidance device shown in FIG. 1 described above, a part of the database 1, a route search unit 3, a road shape analysis unit 4, a route guidance text generation unit 5, and a simplified map generation unit 6 may be a route guidance terminal or a simplified map generation unit 6. It can be realized by software processing by a computer of a device such as a mobile communication terminal.

【0020】

Next, the procedure of the route guidance processing in the present embodiment will be described with reference to the flowchart shown in FIG. First, the user input unit 2 is operated by a user who desires directions, and a departure place and a destination are input (step S101). This input operation is performed by displaying a map of the place including the departure point and the destination based on the map data from the database 1 on the display screen of the route guidance device, that is, the display screen of the presentation unit 7, and using the mouse on this map. You can do this by specifying the departure point and destination using a mouse, cursor, pen, key, etc., or by selecting the departure point and destination from a list of landmarks, address names, etc. May be good.

【0021】

Next, the route search unit 3 searches for a route from the departure point to the destination according to the departure point and the destination and the route search condition input by the user (step S102). As a route search method, a method such as preferentially selecting a route with a sidewalk can be considered, but for example, Dijkstra's method known as an algorithm for solving the shortest route can be used. Of course, it is also possible to use another route search method, and the point is that it is sufficient if some route connecting the starting point and the destination can be searched. In some cases, the user may directly specify the route and input the route.

【0022】

As a result of this route search, the route data represented by the nodes and arcs from the starting point to the destination as shown in FIG. 3 is obtained. Nodes and arcs can be represented by items such as those shown in FIGS. 4 (a) and 4 (b). Nodes are junctions in the road network, such as at intersections and corners. An arc is a line connecting nodes, and when multiple arcs are connected to one node, it is possible to extract multiple arcs connected to that node, or from arc to node, from node to node. By following the arc, you can trace a series of road lines.

【0023】

Next, although it is not necessarily necessary in the present invention, in the present embodiment, the route obtained by the route search in step S102 by the route search unit 3 is further described as a starting point portion, a destination portion and, as shown in FIG. 5, for example. It is divided into three parts (path and intersection) other than that (step S103). In this way, the route is divided into three types and used to generate the following directions and to present a simplified map. An example of this route division will be described with reference to FIG.

【0024】

The starting point is the area from the starting point entered by the user to the first target point. In the example of Fig. 5, the departure point is the station, and the area from the station to the post office, which is the first target that appears when heading to the destination, is the departure point. This starting point is an important part in determining the direction in which a pedestrian begins to walk. However, since there is not always a road at the departure point, special explanations may be required in the directions or simplified maps.

【0025】

The destination section is the area from the last appearing target to the destination entered by the user. In the example of Fig. 5, the last target appearing on the route is the school, and from here to the destination. Indicates the area. Since the road network is not always separated by the target location of the pedestrian, a special explanation may be required on the map, directions or simplified map from the last target to the destination. ..

【0026】

Here, the targets are not only post offices and schools, but also buildings that are likely to be landmarks such as banks, movie theaters, restaurants, supermarkets and convenience stores, as well as traffic lights, intersection names, road names, and T-shaped roads. These include road shapes such as intersections, and attachments to roads such as pedestrian bridges and pedestrian crossings, all of which can be used as landmarks when pedestrians walk. The route search unit 3 can acquire information on these targets by referring to the road network data and the landmark data in the database 1.

【0027】

Further, the route and the intersection are roads included in the intermediate route other than the starting point and the destination, and include the intersection, the corner, and the like. The road shape analysis in this embodiment is mainly performed on this intermediate route portion.

【0028】

Next, the road shape analysis unit 4 analyzes the road shape in the route searched in step S102 (step S104). When the route division process of step S3 is performed after the route search of step S2, the road shape is analyzed especially at the route and the intersection in step S104 as described above. The road shape referred to here is mainly the shape of an intersection, and the analysis of the road shape is, for example, how many intersections the intersection is, how many angles are different between the road in the approach direction and the road in the exit direction, and the intersection. It is to analyze the shape of a road that cannot be analyzed only by road network data, such as whether to intersect a thick road or cross an elevated road. The details of such an intersection shape analysis process will be further described later.

【0029】

Next, the route guidance text generation unit 5 searches in step S2 using the road shape data obtained in step S104, the landmark data stored in the database 1, and the route guidance text database included in the database 1. A road guide text including a description of the road shape and a landmark name for guiding the user along the route is generated (step S105).

【0030】

Further, in the present embodiment, in the simplified map generation unit 6, the road shape data obtained in step S104, the target object used for the route guidance, the information obtained by analyzing the road shape data, and the simplified map database included in the database 1 are included. To generate a simplified map using (step S106).

【0031】

Then, the presentation unit 7 presents the route guidance text generated in step S105 in a character string and / or audio display, and presents the simplified map generated in step S106 by image display (step S107).

【0032】

Hereinafter, the processing of each step of FIG. 2 will be described in detail. (Road shape analysis process) First, as a specific example of the analysis process in step S104 by the road shape analysis unit 4, a process for analyzing the shape of an intersection will be described. The road shape analysis unit 4 extracts the road network data in the route searched by the route search unit 3 from the database 1, and for example, as shown in FIG. 6A, the road network data in the vicinity of the intersection is in the direction of travel. Prepare a mask with a size several times the width of the road, and use this mask to cut out the road network data around the intersection to be shape-analyzed.

【0033】

Next, the road network data included in the area (road network cut-out area) cut out using this mask is pattern-analyzed, and the road extending from the intersection to the outside of the road network cut-out area as shown in Fig. 6 (b). Measure the number n of lines (n = 4 in this example) and the direction (angle difference from the approach direction) and width of each road line. By such a road shape pattern analysis, it is possible to determine that the target intersection is a "four-forked road", "a T-shaped intersection", "a Y-shaped three-way intersection", and the like. ..

【0034】

Specifically, when analyzing the intersection shape, the road shape analysis unit 4 first analyzes the road network data of the road network cutting area and converts it into the following seven intersection shape parameters as shown in FIG. .. (1) Number of roads connecting to the intersection n (2) Angle difference θ of the road in the direction of travel with respect to the direction of approach to the intersection_{o o}(3) Angle difference θ of the road other than the traveling direction with respect to the approaching direction to the intersection₁, θ₂(4) Angle difference θ to the left from the direction of travel of other roads connecting to the intersection_L(5) Angle difference θ to the right from the direction of travel of other roads connecting to the intersection_R(6) Road width ratio between the road in the approach direction and the road in the direction of travel R = W_{o o}/ W_i(7) Road width ratio with other roads Q = max (W)_n) / Max (W_i, W_{o o}) In FIG. 7, the angle difference θ in (3)₁, θ₂Is not shown.

【0035】

For example, in the case of the intersection shape shown in Fig. 6 (b), θ₁, θ₂As a parameter other than C (n, θ_{o o}, θ_L, θ_R, R, Q) = {4,75,105,65,100,140} Is obtained.

【0036】

Next, the road shape analysis unit 4 determines the road shape by collating the above-mentioned parameters with, for example, a determination dictionary as shown in FIG. The judgment dictionary in FIG. 8 is based on the relationship between the number of roads (hereinafter referred to as connecting roads) connecting to points of interest such as intersections and corners (corresponding to n above in the case of intersections) and the angle of each connecting road. A table format for determining the road shape including the intersection shape in consideration of the traveling direction of the pedestrian and specifying the "guidance route expression method" indicating to the pedestrian how to proceed on the road. It is a dictionary of.

【0037】

In FIG. 8, the angle of each road (angle difference from the approach direction) is the angle of each connecting road other than the approach direction with respect to the road in the approach direction, θ._{o o}, θ₁, θ₂Corresponds to any of. For example, if the number of connecting roads is two (road in the approach direction and road in the direction of travel), the road shape is a straight road or a corner, and the method of expressing the guidance route is "road" depending on the angle of the road in the direction of travel. "Turn right" or "turn left".

【0038】

On the other hand, if the number of connecting roads is 3, it is a 3-forked road, and if it is 4, it is a 4-forked road intersection. At three junctions, the roads may be divided at approximately equal intervals, if they branch at a "T-junction (or at the end)", or if they branch at a "Y-junction", the direction of travel is straight. Even so, there are various cases, such as when there is a way to enter sideways on the way. Which of these three forked roads corresponds to can be determined by the angle of each of the two connecting roads other than the road in the approaching direction, and the expression method of the guide route can be determined by this.

【0039】

For four-forked roads, depending on the combination of the angles of the three connecting roads other than the road in the approach direction, the guide route can be expressed as "go straight, cross the road", "turn left at the intersection", "turn right at the intersection", etc. Can be specified.

【0040】

The threshold value for determining the angle of each connecting road is not limited to the value shown in FIG. 8, and may be determined empirically by taking a questionnaire or the like. In short, it suffices if some judgment criteria are determined and stored in a database, and the road shape can be analyzed based on this.

【0041】

Further, the intersection shape is determined by the angle θ shown in FIG._L, θ_RIt can also be done by. That is, θ_L, θ_RIf an appropriate threshold is given, such as whether it is in the range of 10 ° to 80 ° or 80 ° to 100 °, for example, in the case of Fig. 9 (a), n = 3, θL = Since θR = 45 °, it is determined that the intersection shape is a Y-shaped road, and in the case of Fig. 9 (b), n = 3, θL = θR = 90 °, so the intersection shape is a T-shaped road. Can be determined.

【0042】

(Route guidance sentence generation process) Next, the route guidance sentence generation process in step S105 by the route guidance sentence generation unit 5 will be described using the flowchart shown in FIG. When generating the route guidance text, the route search unit 3 first performs a simplification process of the route data generated in step S102 (step S201). The simplification process consists of deleting short line segments and merging continuous line segments in the same direction.

【0043】

The former deletion of short line segments is different from the actual direction of travel of the road in order to maintain the connection of the network at the intersection of large roads and the part where medians and overpasses appear on the road. This is a measure against the case where line segments are mixed. In the latter merge process, in order to generate directions for each node, line segments that mean traveling in the same direction are merged with each other to reduce the amount of directions without significantly reducing the amount of information. It is done for the purpose. FIG. 11 shows an example in which the route of FIG. 3 is simplified. By performing such a simplification process of the route data, it becomes easy to generate a route guide text and a simplified map along the route.

【0044】

Next, the landmark data of the landmark along the route simplified by step S201 is extracted (step S202). In the database 1 of FIG. 1, landmark data consisting of items as shown in FIG. 9 is accumulated for each landmark.

【0045】

In FIG. 9, "ID" is a numerical value representing a landmark identifier. "Name" is the name of a landmark, such as a store name or facility name. "Type" indicates the type of landmark such as a gas station or a bank. The "priority" is a numerical value used as an evaluation standard for whether or not to preferentially use the route when searching for a route or when generating a route guidance sentence. The "position" is the X, Y coordinate of the landmark (eg, latitude, longitude).

【0046】

In step S202, only the landmark data of the landmarks along the simplified route required for route guidance is extracted from the landmark data as shown in FIG. 8 of each landmark stored in the database 1. Perform the processing to be performed.

【0047】

Next, a unit guide is generated using the route data simplified in step S201, the analysis result obtained in step S104 by the road shape analysis unit 4, and the landmark data extracted in step S202 (step S203). ). The unit guide text is, for example, (1) a text that guides you from the starting point to the first target, (2) a text that guides you from the target to the target, and (3) a text that guides you from the corner to the target. It is the smallest unit that can be separated as a sentence when giving directions to pedestrians, such as sentences to be performed and (4) sentences to guide from the target to the destination.

【0048】

The unit guide can be generated by using, for example, the distance from node to node, landmarks in the vicinity, the shape of an intersection, and the state of a corner. In particular, when the target is an intersection, the road shape analysis unit 4 determines whether the intersection shape is a 3-junction (T-junction, Y-junction) or a 4-junction, and how to proceed with the 4-junction. Since it can be judged from the judgment dictionary shown in FIG. 8, it is possible to generate an easy-to-understand sentence using the intersection shape.

【0049】

Finally, each unit guide generated in step S203 is synthesized along the route (step S204). As a result, it is possible to generate a route guide sentence that guides the route from the departure point to the destination with a series of sentences.

【0050】

FIGS. 13 (a) and 13 (b) show an example of a route guide text generated based on the present embodiment and a route guide text generated based on the conventional technique. In the route guidance text shown in FIG. 13 (a), the underlined portion is not shown in FIG. 13 (b) and is a text peculiar to the present embodiment.

【0051】

That is, in the route guide sentence of FIG. 13 (b), the sentences of the third and fourth lines are a little difficult to understand in terms of specificity and sentence structure, whereas in the route guide sentence of FIG. 13 (a), for example. , "Intersection" and "branch" are expressions that clearly indicate the shape of the intersection, "T-junction" and "Y-junction", making it intuitively easy to understand. Furthermore, for example, the expression "turn right and proceed 10 m, then turn left and proceed 30 m" in Fig. 13 (b) briefly expresses the road shape "turn the crank 40 m along the road" in Fig. 13 (a). The text is easier to understand.

【0052】

Further, although not shown in the example of this road guide text, the road width ratios R and Q included in the road shape parameters shown in FIG. 7 converted by the road shape analysis unit 4 are calculated by the road guide text generation unit 5. It can also be reflected in the generation of directions. For example, using this road width information, "Go along the Y-junction toward the narrow road on the right side for 50 m." "Go straight for 20 m and turn right at the wide road at the end of the T-junction." It is possible to generate a sentence as a unit guide sentence, and it is possible to generate a very easy-to-understand route guide sentence.

【0053】

(Simplified map generation process) Next, the simplified map generation process in step S106 by the simplified map generation unit 6 will be described with reference to the flowchart shown in FIG. The database 1 has a presentation pattern corresponding to various road shape data obtained by the road shape analysis unit 4 for generating a simplified map, for example, as shown in FIGS. 15 (a) (b) (c) (d). Is registered in advance as an expression model. In this representation model, various presentation patterns shown in FIGS. 15 (a), (b), (c), and (d) are registered as bitmap data in the simplified map database in database 1, and can be used to represent the simplified map. It will be used.

【0054】

When generating the simplified map, first, the representation model corresponding to the road shape data generated by the road shape analysis unit 4 is selected from the database 1 (step S301). For example, the analyzed road shape is represented by the following parameters shown in Fig. 7 at the intersection shape C (n, θ)._{o o}, θ_L, θ_R, R, Q) = {4,75,105,65,100,140}, it is assumed that the following four types of expression models are registered in database 1 corresponding to these. Turn <CROSS> to <TURN>. Turn the corner of <MARK> to <TURN>. Turn in front of <MARK> to <TURN>. Turn <TURN> at the crossroads <DIST> m ahead of <MARK>. Here, <CROSS> is the name of the intersection, <MARK> is the name of the landmark, <TURN> is the direction of the left or right turn, and <DIST> is the distance to the intersection.

【0055】

Next, the landmark data corresponding to the representation model selected in step S301 is extracted from database 1 (step S302). For example, in the case of the intersection shape shown in FIG. 6, a landmark search area is set around the intersection corresponding to the selected expression model as shown in FIG. 16, and landmark data is searched from each landmark area. Extract.

【0056】

When the target landmark data is extracted in step S302, information such as the landmark name, the name of the intersection, and the distance from the intersection is added to the representation model selected in step S301 to generate a guide route ( Step S303).

【0057】

Finally, by connecting the expression models (presentation patterns) obtained corresponding to each intersection, turn, etc., and generating a map from the departure point to the destination along the guide route generated in step S303. (Step S304), the generation of the simplified map is completed.

【0058】

FIG. 17 is an example of the guide route generated in step S303, and is shown here in sentences for the sake of clarity. FIG. 18 is an example of the simplified map generated in step S304, and the guidance route shown in FIG. 17 is bitmapped by combining the representation models shown in FIGS. 15 (a), (b), (c), and (d). It is expressed as a format map.

【0059】

In this way, a presentation pattern consisting of bitmap data for a simplified map corresponding to various patterns of road shape data generated by the road shape analysis unit 4 is registered in database 1 in advance as an expression model, and the road shape is registered. By combining the representation models corresponding to the road shape data actually obtained by the analysis unit 4, it is possible to easily generate a simplified map along the guide route.

【0060】

In addition, various presentation patterns as shown in FIGS. 15 (a), (b), (c), and (d) are registered as text data in the route guidance database in the database 1, and obtained by the road shape analysis unit 4. It is also possible to read out the presentation pattern corresponding to the road shape data to be generated and generate a route guide. Further, the text of the guide route shown in FIG. 17 may be generated as it is as a route guide text.

【0061】

The flowchart shown in FIG. 19 shows another example of the simplified map generation process in step S106 by the simplified map generation unit 6. In this example, the database 1 corresponds to various road shape data obtained by the road shape analysis unit 4 for the purpose of generating a simplified map, as shown in FIGS. 20 (a) (b) (c) (d), for example. Presentation pattern is registered in advance as an expression model. In this expression model, various presentation patterns shown in FIGS. 20 (a), (b), (c), and (d) are registered as vector data in the simplified map database in database 1, and are used for expressing the simplified map. Will be done.

【0062】

When generating the simplified map, first, a representation model consisting of vector data corresponding to the road shape data generated by the road shape analysis unit 4 is selected from the database 1 (step S401). Next, the landmark data corresponding to the representation model selected in step S401 is extracted from database 1 (step S402). For example, in the case of the intersection shape shown in FIG. 6, the landmark data of the landmarks existing in each area around the intersection corresponding to the selected expression model as shown in FIG. 16 is searched and extracted. When the target landmark data is extracted in step S402, information such as the landmark name, the name of the intersection, and the distance from the intersection is inserted into the corresponding representation model to generate a guide route (step S403).

【0063】

Next, an expression model (presentation pattern) consisting of vector data obtained corresponding to each intersection or the like is connected along the guide path generated in step S403 (step S404), and further shaped to form the guide path. By generating a map from the starting point to the destination along the route (step S405), the generation of the simplified map is completed.

【0064】

FIG. 21 is an example of a simplified map obtained in step S404 via step S403, and since the vector data are connected as they are, many arrows are included.

【0065】

On the other hand, in FIG. 22, the arrow of the passing point is removed from the simplified map obtained in step S404, and the shaping process of leaving the vector end arrow only at the important points such as the starting point, the destination, and the corner is performed in step S405. It is a simplified map obtained. By removing unnecessary arrows of the vector in this way, an easy-to-understand simplified map can be generated.

【0066】

In this way, the presentation pattern consisting of vector data for a simplified map corresponding to various patterns of road shape data generated by the road shape analysis unit 4 is registered in the database 1 in advance as an expression model, and the road shape analysis is performed. By combining the representation models corresponding to the road shape data actually obtained by Part 4, a simplified map along the guide route can be easily generated.

【0067】

In this case, unlike the previous example, the presentation pattern, which is an expression model, is stored in the database 1 as vector data with a significantly smaller amount of data than the bitmap data, so that the load on the database 1 is reduced and the load on the database 1 is reduced. The processing amount of the route guidance device is also reduced, and the speed can be increased.

【0068】

In addition, since vector data can be easily shaped by removing unnecessary information from the simplified map as described above, especially when the display screen such as a mobile communication terminal provides directions with a small device. However, there is an advantage that an easy-to-read simplified map can be presented to the user.

【0069】

In the explanation so far, the case where the intersection shape is mainly analyzed to provide the route guidance has been described, but it is also effective to analyze the shape of the rotary such as in front of the station as another road shape and reflect it in the route guidance.

【0070】

FIG. 23 shows a typical rotary arrangement found in front of a station. Suppose you are giving directions when a pedestrian transfers from a station to a bus. FIG. 24 is an example of the road network in the rotary in this case. In order to transfer from a station to a bus in the rotary, you must go to the bus stop through the underpass route C instead of the ground roads route A and B around the rotary. If you don't have an underpass, you may cross the pedestrian crossing to the bus stop.

【0071】

With a special road shape that is different from general roads that include intersections, it is not possible to provide sufficient route guidance simply by analyzing the structure of the road network. That is, although there are no ordinary roads such as roadways and adjacent sidewalks, it is necessary to determine the area where pedestrians can walk.

【0072】

In the example of FIG. 24, the four road networks existing in front of the station are in a closed loop, and an area called a plaza exists in the closed loop. The plaza surrounded by roads is often used as a bus depot or parking lot, so it can be judged as a rotary in front of the station.

【0073】

In this way, for the rotary, the road shape analysis unit 4 can analyze where the area where pedestrians can walk is from the relationship between the station, the road network, and the plaza. In addition, when the road network data is generated in advance, by generating the network data such as the underpass that crosses the plaza, the route search unit 3 does not sequentially determine whether or not it is a plaza, and the route search. It can be performed.

【0074】

[Effect of the invention]

As described above, according to the present invention, the road shape such as an intersection on the route from the starting point to the destination is analyzed macroscopically, and the analysis result is reflected in the route guidance information, which is useless or redundant. It is possible to appropriately remove expressions to generate intuitively very easy-to-understand route guidance information and present it to a user who is a pedestrian.

[Simple explanation of drawings]

[Figure 1]

A block diagram showing a configuration of a route guidance device according to an embodiment of the present invention. [Figure 2]

Flow chart showing the flow of route guidance processing in the same embodiment [Fig. 3]

Diagram showing an example of the route to be searched [Fig. 4]

Diagram showing structural examples of nodes and arcs that make up route data [Fig. 5]

Diagram showing an example of route division [Fig. 6]

Diagram showing road network data near the intersection and an analysis example of the shape of the intersection [Fig. 7]

The figure explaining various parameters representing an intersection shape [Fig. 8]

A diagram showing a judgment dictionary for judging the expression method of the road shape including the intersection shape and the guide route from the relationship between the number of roads connected to the intersection or the corner and the angle. [Fig. 9]

The figure which shows the analysis example of the intersection shape [Fig. 10]

A flowchart showing the flow of the route guidance sentence generation process in Fig. 2. [Fig. 11]

Diagram showing an example of a simplified route [Fig. 12]

Diagram showing an example of landmark data [Fig. 13]

The figure which shows the example of the route guidance sentence generated by the same embodiment in comparison with the example of the route guidance sentence based on the prior art. [Fig. 14]

A flowchart showing the flow of the first example of the simplified map generation process in FIG. [Fig. 15]

A diagram showing an example of a presentation pattern consisting of bitmap data corresponding to various road shape data for generating a simplified map registered in a database. [Fig. 16]

Diagram showing an example of a landmark search area [Fig. 17]

Diagram showing an example of the generated guidance route [Fig. 18]

A diagram showing an example of a simplified map in bitmap format along the generated guidance route. [Fig. 19]

A flowchart showing the flow of the second example of the simplified map generation process in FIG. [Fig. 20]

A diagram showing an example of a presentation pattern consisting of vector data corresponding to various road shape data for generating a simplified map registered in a database. [Fig. 21]

A diagram showing an example before shaping a simplified map in vector format along the generated guide path. [Fig. 22]

A diagram showing an example after shaping a simplified map in vector format along the generated guide path. [Fig. 23]

Diagram showing a typical layout example of the rotary in front of the station [Fig. 24]

Diagram showing an example of the road network in the rotary in front of the station [Explanation of symbols]

1 ... database 2 ... User input section 3 ... Route search section 4 ... Road shape analysis department 5 ... Directions text generator 6 ... Simplified map generator 7 ... Presentation section