JP3841776B2 - Route search device - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a route search device that automatically calculates an optimal travel route connecting a set start point and end point.
[0002]
[Prior art]
2. Description of the Related Art A navigation device has been put to practical use that displays a map image with a vehicle position mark at the center of the screen on a liquid crystal screen or the like, and provides route guidance to an operator. The vehicle-mounted navigation device calculates an actual vehicle position from a GPS (Global Positioning System) device, a vehicle speed sensor, a direction sensor, and the like, and synthesizes and displays the calculation result on a map screen.
[0003]
The in-vehicle navigation device includes, for example, a CD-ROM device storing map information, calls necessary map information from the CD-ROM device, and displays a map image of a predetermined range centered on the vehicle position on the liquid crystal screen. indicate.
[0004]
In the CD-ROM storing the map information, data of a large number of information points (hereinafter referred to as nodes) on the map and data of links connecting the two nodes are recorded together with the map image. Road intersections, dead ends, railroad crossings, railway stations, interchanges, etc. are selected as nodes. Also, latitude, longitude coordinate information, intersection name, direction of travel guidance, right / left turn prohibition, etc. are added as node information, and road width, one-way traffic, etc. are added as link information.
[0005]
Therefore, while driving, the driver checks the actual vehicle position on the map screen, but the navigation device has a function of searching the CD-ROM with the coordinates of the current position and the traveling direction, so that the passing node ( Data on approaching intersections) can be used in real time.
[0006]
For example, at a few hundred meters before the intersection, the traveling direction of the next intersection, lane guidance, presence / absence of one-way traffic, etc. are displayed superimposed on the corners of the map screen. In addition, the vehicle mark that moves off the road on the map is automatically returned to the road.
[0007]
A route search function has been put to practical use as an auxiliary function of a navigation device using node information and link information recorded on a CD-ROM. The route search function is a function in which the navigation device calculates an optimal travel route prior to the start of actual travel.
[0008]
Once the driver sets the start point and end point, the calculation unit of the navigation device automatically searches the CD-ROM, calls the necessary node information and link information, and sets the shortest distance, the shortest time, etc. Calculate the travel route that meets the conditions.
[0009]
For example, a CAD image is formed by connecting the coordinates of nodes located along the travel route, combined with a map image, and displayed as an image. As a result, the travel route is indicated by a bold line on the map image.
[0010]
For example, when actually traveling along a set travel route, each time the vehicle approaches an intersection, the distinction between right turn, left turn, and straight travel for realizing the travel route is combined and displayed in the corner of the map image. The speed limit, lane guidance, and the like may be displayed together. In some cases, the navigation device is provided with a speaker, and such information is transmitted by voice.
[0011]
As a travel route calculation method, a calculation method called Dijkstra method has been well known. In the Dijkstra method, the link lengths are added in order from the start point to the outside, and the shortest route to reach the outer node is sequentially determined, and the shortest distance travel route to finally reach the end point is determined. To do.
[0012]
However, in the Dijkstra method, the number of nodes to be calculated (range involved in the calculation) increases in area as the calculation proceeds from the start point, so it takes a long time to calculate the long distance traveled. There is a problem that a large capacity is required for the memory capacity that temporarily stores the calculation data and enables the calculation device to perform the next calculation.
[0013]
The Dijkstra method only finds a travel route that realizes the shortest path in length, and there is no guarantee that the travel time will be the shortest even if the travel route is adopted. That is, an inefficient driving route may be obtained in light of actual driving feelings and common sense, such as selecting a narrow road and repeating left and right turns.
[0014]
In view of this, attempts have been made to use the Dijkstra method in various modifications by weighting the nodes and links by further effectively using the node information and link information recorded on the CD-ROM.
[0015]
For example, in Japanese Patent Application No. 4-329564, the applicant of the present application proposes a method of calculating a “traveling route that achieves the shortest travel time” by converting the link length into a link travel time and integrating the link length.
[0016]
[Problems to be solved by the invention]
While the route search process is being executed in the navigation device, the navigation device is not currently capable of executing normal map display. This is because the calculation unit of the navigation device performs a huge amount of calculation for the route search process, and there is no room for normal processing to interrupt. In addition, the memory for temporary storage attached to the calculation unit also stores calculation data read from the CD-ROM and stores calculation results that gradually increase in the determined nodes and links. I can't allocate much.
[0017]
Therefore, during the route search process, the navigation device apparently stops operating at all, and the operator may be anxious and suspect a failure. For this reason, there are proposals for blinking lamps or displaying a bar graph on the liquid crystal display during the route search process to display the progress of the calculation, which has some effect.
It is an object of the present invention to further devise the display during the route search process and to display more useful for the user.
[0018]
[Means for Solving the Problems]
FIG. 1 is an explanatory diagram of the route search apparatus according to the embodiment. Here, the route search apparatus of each claim will be described with reference to symbols attached to the system configuration of FIG. However, the route search device of claim 1 is not limited to the mode described in FIG. 1 and the description of the embodiment.
[0019]
The route guidance device in FIG. 1 includes a first storage unit 13 that stores information on a number of nodes and links on a map in combination with a map image, and an operation unit that can set the start point and end point of a desired travel route. 11 and the node and link information stored in the first storage means 13, the travel route is calculated in a form that sequentially extends the determined travel route from at least one of the start point and end point. In a route search device having a calculation means 16 and a second storage means 15 that sequentially stores the determined travel route and enables the calculation means 16 to calculate a continuation portion of the travel route, A pair of display means 17A, 17B capable of displaying the ratio almost continuously, and the ratio of the determined travel route to the entire travel route to be obtained are detected and one of the display means 17 is detected. In addition, the remaining amount of the storage capacity of the first measuring unit 16 and the second storage unit 15 for performing display substantially corresponding to the ratio is detected, and the other display unit 17B substantially corresponds to the remaining amount. Second measuring means 16 for performing display.
[0020]
The route search device according to claim 1 searches for a travel route between the set start point and end point,
In the route search device that performs route guidance based on the searched route, the fact that the route is being searched,
In-search notifying means for displaying with a bar graph extending as the route search process proceeds, and end point name displaying means for displaying the place name of the set end point during the route search process.
Accordingly, the fact that the route search is being performed during the route search process is displayed as a bar graph that expands as the route search process proceeds, and the place name of the end point is displayed.
[0021]
The route search device according to claim 2 is the route search device according to claim 1, wherein the in-search notification means includes:
The bar graph is made to be 100% long when the route search is completed and the search result can be output.
Therefore, a bar graph indicating that a route is being searched can be displayed at an appropriate timing during the route search process.
[0022]
The route search device according to claim 3 is the route search device according to claim 1 or 2, further comprising start point name display means for displaying the place name of the set start point during route search. It is what.
Accordingly, the place name of the end point is displayed during the route search process.
[0023]
The route search device according to a fourth aspect is the route search device according to the first, second, or third aspect, wherein the place name of the end point is attached to a proximity point of the end point searched based on the end point. It is a place name.
Therefore, the place names of the close points (points with place names) of the end points are displayed during the route search process.
[0024]
【Example】
FIG. 1 is an explanatory diagram of a navigation apparatus according to an embodiment of the present invention, FIG. 2 is an explanatory diagram of a processing program, and FIG. 3 is an explanatory diagram of display contents. In FIG. 1, (a) shows a system configuration and (b) shows a processing block diagram. In FIG. 3, (a) shows the screen configuration and (b) shows the distance calculation.
[0025]
Here, a route search function is provided as an auxiliary function of the vehicle-mounted navigation device. The operator selects a route search process, calls a map on the screen of the vehicle-mounted navigation device, and inputs a start point and an end point. Then, the map screen of the in-vehicle navigation device shifts to a screen indicating that the route search process is in progress, and the progress of the route search process and the memory capacity usage (total capacity-remaining amount) are displayed as a bar graph.
[0026]
In FIG. 1, in the case of normal traveling, the processing unit 16 calculates the momentary vehicle position based on the position and speed information obtained from the position sensor 14. Then, a map screen including the vehicle position is called from the map database 13 to form image data. The image data is displayed to the driver through the display unit 17 as a map screen with the vehicle mark positioned at the center of the screen.
[0027]
In the lower part of the map screen, the presence / absence of various information such as intersection name, intersection structure, lane guidance, road name, speed limit, etc. is displayed. Select and use.
[0028]
The map database 13 is composed of a CD-ROM playback device, and searches for map image data, node information, and link information in response to a search command from the processing unit 16 and sends it to the processing unit 16. The memory 15 temporarily stores processing data when the processing unit 16 executes various arithmetic processes.
[0029]
When the driver designates a start point (home) and an end point (destination) through the operation unit 11, the processing unit 16 searches the map database 13 for necessary node information and link information, and travels the route with the shortest travel time. Configure.
[0030]
When using the route search function, the operator selects a route search process through the input unit 11. The operator scrolls the map displayed on the screen of the display unit 17 through the input unit 11, selects a necessary map, and inputs a start point. Subsequently, the operator scrolls the map displayed on the screen of the display unit 17 through the input unit 11, selects a necessary map, and inputs an end point. Then, the operator commands the start of the route search process.
[0031]
As a result, the map screen of the display unit 17 immediately shifts to a screen indicating that the route search process is in progress, and displays two bar graphs 17A and 17B. The bar graph 17A indicates the progress of the route search process. The bar graph 17 </ b> B displays the proportion of the capacity that can be allocated to the route search process in the memory 15 that is already used at the present time.
[0032]
Thereafter, the calculation is continued for several minutes. If the bar graph 17B does not reach 100% in the middle (if the memory 15 does not overflow), all the calculation processes are completed and the calculation progress of the bar graph 17A reaches 100%. Is displayed. The operator calls the recording operation screen shown in FIG. 9B on the display unit 17 and records the route search result on the IC card of the route data storage unit 12. The route search result may be sent to the route data storage unit 12 at the same time as the calculation is completed, and the recording operation may be automatically performed.
[0033]
The travel route data formed in this way includes node information and link information of the nodes constituting the travel route from the start point to the end point. In addition, guidance data such as a right turn, a left turn, and a straight line for configuring a travel route is added to the node information.
[0034]
The route data storage unit 12 sends the travel route data to the data processing unit 16 in response to a command from the data processing unit 16. In addition, it is possible to share the travel route data with the indoor system using a personal computer or the like by extracting the IC card from the route data storage unit 12.
[0035]
In FIG. 1B, the processing unit 16 in FIG. 1A can execute a route guidance process 22 in addition to the normal vehicle position detection process 23 and the route search process 21 described above. The route guidance process 22 is a process of providing real-time information to the operator during traveling based on the data of the traveling route recorded in the route data storage unit 12 of FIG.
[0036]
For example, the position of the vehicle is compared every moment with respect to the set travel route, and a message notifying a right turn is output before an intersection that requires a right turn on the travel route. In addition, an alarm is output when the travel route is deviated.
[0037]
The route search processing 21 includes a point setting 21A for determining a start point and an end point based on an operator's designation, a route search 21C for actually calculating a route by a modified Dijkstra method, and the calculated search result 21D. Each process of the search result management 21B to be recorded on the IC card in a form combined with other necessary sorting information is included.
[0038]
In FIG. 2, bar graphs 17A and 17B are displayed on the display screen of the display unit 17 of FIG. 1 during the route search process. The bar graph 17A displays the progress of the route search process, and the bar graph 17B displays the usage rate of the memory 15.
[0039]
The “distance from the starting point to the end point” calculated in step 26 is compared with the “distance from the start point to the end point” calculated in step 25 at the bottom of the flowchart. The ratio of the two is displayed as a bar graph (hereinafter referred to as an indicator) in step 28. The determined straight line distance d and the remaining straight line distance D-d to the end point are also displayed together.
[0040]
However, in the calculation process of step 27, even if the remaining straight line distance D-d becomes 0, it is handled as 90%. The indicator display of 100% is realized by step 30 in a time when all the route search processes are completed and the calculation result can be output.
[0041]
Similarly, the capacity m that is actually used (or still free) is compared with the maximum capacity M that can be allocated to the route search process in the memory 15. The ratio between the two is displayed as an indicator in step 29. The capacity m being used and the remaining amount Mm are also displayed in text.
[0042]
In FIG. 3 (a), place names of the start point and end point are displayed on the display screen during the route search process. The place name is determined from the node information of the neighboring nodes searched based on the start point and end point set by the operator.
[0043]
In FIG. 3B, the straight line distance d for determining the progress of the route search process is calculated from the XY coordinate values included in the node information. Further, the linear distance d is calculated once for each map unit.
[0044]
The road map data is usually managed in units as shown in Fig. 3 (b). When the point being searched is in the lower left (20, 20) unit, the distance L to the unit where the goal exists is
L2 = (60-20) 2 + (0-20) 2
Is required.
[0045]
While the search point exists in the unit being searched, distance calculation is not necessary, and the processing speed can be increased. When the search point moves to the unsearched unit, the distance is calculated, and when the distance becomes larger than the previous value, the indicator amount may be calculated based on the distance.
[0046]
By the way, if the search point exists in the unit being searched for a long time, the indicator does not move. Therefore, the indicator amount is not increased at a time for one unit, and the period during which the search point exists in the same unit is increased for each minimum step of the indicator.
[0047]
FIG. 4 is an explanatory diagram of the point setting function. Here, a flowchart of the point setting prohibition check process is shown.
[0048]
In FIG. 4, in the point setting 21 process of FIG. 1 (b), setting of the start point and end point using other than the detailed map is prohibited. The map recorded on the CD-ROM has a plurality of layers with different scales. By using a detailed map with a small scale, the position setting position accuracy is ensured.
[0049]
The display map scale s of the map selected by the operator and displayed as an image is compared with the allowable level S of roughness. The display map scale s is updated when the display map is enlarged or reduced when the map is first drawn. If the map is not a detailed map, for example, an alarm “Please set with detailed map” is displayed. In the case of a detailed map, it is possible to continue to set actual points.
[0050]
FIG. 5 is an explanatory diagram of creation of parent-child relationship data of nodes, FIG. 6 is an explanatory diagram of a hierarchical route search, and FIG. 7 is an explanatory diagram of a hierarchical route search result. In FIG. 5, (a) shows a processing flowchart, and (b) shows a data structure. Here, in order to perform a hierarchical route search, calculation data used prior to the calculation process is organized.
[0051]
In FIG. 5 (a), during the route search process, node information and link information retrieved from the map database 13 are temporarily stored in the memory 15 of FIG. 1 (a) for each map of the unit block. Will be provided sequentially. At this time, the node information of the upper (lower) map is also referred to, and the parent-child relationship of the node is added to the node information and recorded. In other words, the identity of the XY coordinates of the node information is checked, and all the nodes in the lower map that overlap the nodes in the upper map are selected. This makes it possible to identify whether or not the calculation can be continued on the upper map when the calculation is performed on the lower map node.
[0052]
At this time, the condition is that (1) the map data has a hierarchical data structure, and (2) the data indicating the parent-child relationship of the nodes is not added between the maps in the hierarchy.
[0053]
In FIG. 5B, the header of the map data 41 stores a map data number, a map scale, a data size, latitude / longitude information, and the like. The node table stores node coordinates, connection link information, presence / absence of a parent / child node, and the like. The link table stores the start node number, end node number, type, width, traffic regulation, link length, link direction, and the like.
[0054]
The parent (child) node table 42 arranges parent (child) data 1 to n, and one parent (child) data 43 includes a parent (child) data number and a connection node number.
[0055]
In FIG. 6, using the relationship between the parent and child nodes in FIG. 5 (b), a route search is performed for a road map in a higher hierarchy as the search starts and ends. In other words, the search is started with the detailed map at the lowest layer where the start point is set, and the route search progresses to the child node where the coordinate value of the child node of the detailed map matches the coordinate value of the parent node of the upper map and overlaps. This time, the route search by the parent node of the upper map is started. When the route search progresses in the upper map and reaches a parent node that overlaps the parent node of the upper map, the route search by the parent node of the higher map is started.
[0056]
On the other hand, the route search proceeds in the same procedure from the end point side. The search is started with the detailed map at the lowest layer, and the route search is advanced by switching to the upper map and the upper map. The route search is completed when the route search from the start point and the route search from the end point reach the common node for the first time.
[0057]
The processing procedure is as follows. (1) Determine the search start and end nodes at the lowest level. (2) Use the parent node data from the start node to determine the route to the upper layer. (3) Use the parent node data from the end node to determine the route to the upper layer. (4) Determine the route between higher layers. (5) Check the route, that is, search for the route near where the hierarchy changes again, and optimize it. In (2) and (3), it is determined based on the distance between the start point and the end point and the road (data) density as to which level to rise.
[0058]
In FIG. 7A, the search in the same hierarchy has the following problems. (1) When the top layer is used, there is no detailed route around the start and goal. (2) When the lowest layer is used, the search distance is shortened because the data size is large.
[0059]
In FIG. 7B, in the hierarchical search, the lowest layer is used around the start and goal. Use higher layers as you move away from the start and goal. Therefore, there are detailed routes around the start and goal.
[0060]
FIG. 8 is an explanatory diagram of the map cutout method in the search. In the figure, (a) shows the relationship between the end point direction and the link direction, and (b) shows the link weight for the end point.
Here, the link is weighted according to the direction of travel to promote the progress of the computation toward the computation end point.
[0061]
In FIG. 8A, the route search proceeds in the following procedure. (1) The direction Dg with respect to the search end point G is obtained from the searching node N. (2) The road direction Dl connected from the node N is obtained. (3) Find the difference Δd between Dl and Dg. A weight w is calculated from Δd. (5) The w obtained in (4) is used for weighting the links during route search. (6) When the search point reaches the boundary of the map data, the adjacent map data is read. Therefore, map data is not prepared in advance by cutting out an ellipse before searching.
[0062]
Such a process also has a map cutout function while being a part of the search process. This is because the search can easily proceed in the direction of the end point by shortening the link length toward the end point.
[0063]
In FIG. 8B, as Δd is 0, that is, as the degree of coincidence between the link direction and the end point direction is higher, the weight is assigned smaller. As the degree of coincidence between the link azimuth and the end point azimuth decreases, the weight gradually increases and becomes maximum in the opposite direction (180 degrees).
[0064]
The weighted link length L corrected by weighting is as follows: l: link actual length, W1: multiplication weight, W2: addition weight, w: weight for search end point,
L = 1 × W1 × w + W2
Is required. A route search process using the Dijkstra method or the like proceeds in a form in which the weighted link lengths L are sequentially integrated.
[0065]
Next, the memory release function will be described. Here, the capacity of the memory 15 in FIG. 1A is saved during the route search process.
[0066]
When the road data used in the search is divided into blocks as shown in FIG. 3B, the road data area of the section in which the route length from the search start point to all the nodes existing in the section is determined is stored in the memory 15. Release from the top. This reduces memory consumption.
[0067]
There is no need to refer to the node once confirmed, so when the route length to all the nodes existing in one block is confirmed, the road data of that block is released and the memory capacity that can be used in the route search processing is increased. Let Thereby, even if the memory 15 having the same capacity is used, the distance that can be searched for a route increases.
[0068]
Next, the data thinning function will be described. Here, during the route search process, the map data is screened when the node information and link information used for the latest calculation are stored in the memory 15 from the map database 13 of FIG.
[0069]
When the straight-line distance to be searched is longer than a predetermined value, only a specific road type is extracted from the road data on the way, and is stored in the memory 15 as map data. This extraction operation is performed by temporarily storing node information and link information for each block from the map database 13 in the memory 15, and the data of the block for which extraction has been completed is immediately released from the memory 15.
[0070]
Then, using only node information and link information related to a specific road type, a route search process from a block including the start point (or a neighboring block) to a block including the end point is executed. The route search in the block including the start point and the block including the end point may be performed separately and the results may be added. As a result, the number of nodes to be searched is greatly reduced, and the processing speed and memory consumption are reduced.
[0071]
For example, route search processing is performed by extracting only expressways. However, initial data reading reads all roads. At this time, the interchange on the route on the expressway is a node that forms a branch in the original data, but is a dead end having no connection relationship in the data after thinning. Therefore, there is no fear that the calculation range extends outside the expressway with these nodes as base points.
[0072]
For example, (1) Extract only highways, completely eliminate unnecessary areas, rearrange data, and close down. In this case, since the useless area is eliminated, the data size is minimized, but compatibility with the original data recorded on the CD-ROM is lost.
[0073]
Or (2) The node number and link number are changed only in the connection relationship while maintaining compatibility with the original data. When it is necessary to maintain compatibility in relation to processing (display, route guidance, etc.) other than route search, data is thinned out by this method. In this case, the overall data size is slightly larger, but compatibility with the original data can be ensured through the node number and link number. For example, if the format of 0, 1, 2,... N is adopted in the order stored in the node number = node table, the number of nodes does not decrease. The same applies to links.
[0074]
The determination condition for this function to function effectively is when the distance for the route search is longer than the longest straight distance on land where the expressway does not pass. The condition for starting this function is when the distance from the start point (or end point) to the expressway is fixed. Accordingly, when the operator sets the start point and the end point, these conditions may be determined, and when the conditions are met, the function may be automatically switched to this function.
[0075]
Next, a route search function up to a specific road type will be described. If a specific road type is an expressway, for example, this function is an agreement with the “route search function to the nearest expressway”.
[0076]
In a normal route search process, a route from a search start node to a search end node is obtained. In this case, the end of the search process is determined when the path length to the search end node is determined.
[0077]
In contrast, in this function, the search end determination condition is changed to “when the route length to a node connected to a link of a specific road type is first determined”. Thereby, the subsequent calculation processing is executed by the same calculation method and calculation procedure as in the case of the normal route search processing.
[0078]
In addition, a switch for switching between a normal “route search process not specially handling an expressway” and a route search process by this function is provided, and an end condition of the search process is switched after waiting for an operator's command.
[0079]
FIG. 9 is an explanatory diagram of a search result storage and update function. In the figure, (a) shows the recording method and (b) shows the display screen. Here, the operation when the route search result is recorded on the IC card in the route data storage unit of FIG.
[0080]
In FIG. 9 (a), the storage capacity of the SRAM of the IC card is used in an indefinite type in which a certain storage space is not divided in advance. On the other hand, in the fixed type in which the recording capacity is divided in advance by a fixed storage space, there are problems that the route search result exceeding the storage space cannot be stored, and the overall storage efficiency is low.
[0081]
For example, when a 40-Kbyte SRAM 71 is divided into four storage addresses in advance, a route search result of 10 Kbytes or more cannot be stored, and even if an empty space is generated for each storage address, it cannot be filled later.
[0082]
On the other hand, when the 40-Kbyte SRAM 72 is used indefinitely, a plurality of past route search results are packed up without forming an empty space in the middle, and the storage efficiency is increased. Then, a new route search result can be stored in the empty space 72B.
[0083]
In FIG. 9B, when a new route search result is stored, the operation screen 73 is output to the display unit of FIG. The operator operates the operation panel 74 while viewing the operation screen 73. Thereby, a new route search result is recorded on the IC card, and the recorded content of the IC card can be edited.
[0084]
The operation screen 73 displays a list display 73A of recorded route search results, a selection mark 73B, a data amount display 73C of a new search result, a storable / impossible display 73D, and a storable capacity display 73E. On the operation panel 74, cursor movement switches 74A and 74B, a selection confirmation switch 74C, a save switch 74D, and an erasure switch 74E are arranged.
[0085]
When the operator stores the search result randomly (indefinitely) on the SRAM 72 of the IC card, (1) If there is a free area 72B in the memory that can hold a new route search result, the free area 72B Holds a new route search result. In this case, the storable / impossible display 73D on the display screen 73 is displayed as storable, and if the operator operates the save switch 74D, recording is immediately executed.
[0086]
However, (2) in the case where the SRAM 72 does not have a free area 72B for holding a new route search result, the size and free capacity of the result specified by the operator to be deleted among the results recorded in the past. The added numerical value is output to the storable capacity display 73E. This is size A. Also, the numerical value of the size of the new route search result is output to the data amount display 73C of the new search result. This is size B.
[0087]
Further, the size relationship between the sizes A and B is checked, and the size is output to the storable / impossible display 73D. Whether or not it can be held is determined by “size A ≦ size B”. When this relationship is established, “saveable” is displayed.
[0088]
The designation of deletion by the operator is performed by the operator moving the cursor movement switches 73A and 73B based on the list display 73A on the display screen 73 and operating the selection confirmation switch 74C. A selection mark 73B is output for the designated route search result. A numerical value obtained by adding the capacity of the designated route search result (s) to the capacity of the empty area 72B is output to the capacity display 73E. If the operator operates the save switch 74D at the stage where the save / impossible display 73D is displayed, the designated route search result is immediately erased, and the remaining route search results are recorded in the SRAM 72 as a head. A new route search result is recorded in the formed empty space.
[0089]
The processing procedure when the result is updated (replaced) is as follows. (1) Delete the data specified by the operator. (2) Move the result area (memory copy) to fill the deleted area. This is to secure a continuous free area. (3) Record new results in free space.
[0090]
When the SRAM 72 does not have a free area 72B that can hold a new route search result, a combination of route search results satisfying the relationship of “size A ≦ size B” is displayed without waiting for the operator's designation operation. 73 may be displayed.
[0091]
The following method can be adopted as a method for selecting the route search result to be posted on the erasure recommendation list. (1) If it is possible to record a new route search result simply by deleting one route search result, that one route search result is selected. (2) If a new route search result cannot be recorded without deleting a plurality of route search results, the combination that minimizes the number of route search results to be deleted and minimizes the total size is selected. (3) Select the oldest route search results in order. These automatic selection functions may be arbitrarily selected by the operator.
[0092]
【The invention's effect】
According to the route search device of claim 1, the fact that the route search is being performed during the route search is displayed as a bar graph that expands as the route search process proceeds, and the place name of the end point is displayed. The operator can feel at ease and the end point setting can be confirmed.
[0093]
In the route search device according to the second aspect, during the route search, the place name of the start point is also displayed together with the bar graph indicating that the route is being searched and the place name of the end point, so that the setting of the start point can be further confirmed.
[0094]
In the route search device according to the third aspect, since the place name of the end point is displayed during the route search, the setting of the end point can be confirmed.
[0095]
In the route search device according to the fourth aspect, since the place name existing near the end point is detected and displayed, the setting confirmation of the end point is further easily understood.
[0096]
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a route search apparatus according to an embodiment.
FIG. 2 is an explanatory diagram of a processing program.
FIG. 3 is an explanatory diagram of display contents.
FIG. 4 is an explanatory diagram of a point setting function.
FIG. 5 is an explanatory diagram of creation of parent-child relationship data of nodes.
FIG. 6 is an explanatory diagram of a hierarchical route search.
FIG. 7 is an explanatory diagram of a hierarchical route search result.
FIG. 8 is an explanatory diagram of a map cutout method in search.
FIG. 9 is an explanatory diagram of a search result storage and update function;
[Explanation of symbols]
11 Input section
12 route data storage unit (third storage means)
13 Map database (first storage means)
14 Position sensor
15 Memory (second storage means)
16 Processing unit (calculation means, etc.)
17 Display
17A Bar graph (first display means)
17B Bar graph (second display means)

Claims (4)

A travel route between the set start point and the end point and search process, the route search device for performing route guidance based on the searched route,
In-search notifying means for displaying that a route search is in progress with a bar graph that extends as the route search process progresses,
A route search apparatus comprising: an end point name display means for displaying a place name of the set end point during route search processing . In the route search device according to claim 1,
The in-search notifying means sets the bar graph to 100% length when the route search is completed and the search result can be output. In the route search device according to claim 1 or 2,
A route search device comprising start point name display means for displaying a place name of the set start point during route search. In the route search device according to claim 1, claim 2, or claim 3,
The route search device according to claim 1, wherein the place name of the end point is a place name given to a close point of the end point searched based on the end point.

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