JP6067237B2 - Map drawing data generation method - Google Patents

Description

  The present invention relates to a technique for improving the visibility of a portion where routes overlap when a map is drawn.

Since the map is drawn on a two-dimensional plane, if another road passes under the elevated road, the lower road may be hidden by the elevated road depending on the positional relationship between the two. . Also, because the map is drawn at various scales, two or more roads running side by side may overlap each other depending on the scale when trying to draw at the road width determined according to the road type at the time of drawing. There is. If overlap occurs in a small part of the road, the user can grasp the general shape and connection of the road, but if it overlaps over a long distance, the user cannot grasp the shape and connection of the hidden road, The usefulness of may be impaired. As countermeasures for such problems, there are techniques described in Patent Documents 1 to 3.
Patent Document 1 discloses a technique for drawing a deformed map by shifting an upper road when a road overlaps under an elevated road.
Patent Document 2 discloses a technique for securing a predetermined minimum distance between routes by drawing a less important side when the distance between routes is narrow and it is difficult to identify both in drawing a deformed map. .
Patent Document 3 discloses a technique for identifying and drawing both roads that are drawn in an overlapping manner by shifting both of them horizontally by half the width of the road.

Japanese Patent Laid-Open No. 10-177338 JP 2004-361828 A JP 2006-1113013 A

In the prior art, it is possible to draw a map so that both of the roads where the overlapping occurs appear on the map without being hidden.
However, if the road is drawn in a shifted manner, the road is drawn at a position different from the original, which causes a deviation from the actual state. Conventionally, this divergence has not been studied at all. For example, even when only a part of roads overlap, the entire road is drawn with a shift, so there is a possibility that a large divergence may occur from the actual state. was there. This problem is common not only when roads overlap but also when various routes such as roads and railways overlap. In addition, the overlap sometimes occurs not only between two routes but also between three or more routes.
In view of this problem, the present invention aims to improve visibility of overlapping routes while suppressing a deviation from an actual state when drawing a map.

The present invention is a map drawing data generation method for generating map drawing data for drawing a map,
(A) reading route data representing the position and shape of a route that overlaps at least partly;
(B) when one of the routes is set as a reference route, the step of changing the setting width of the other route to be drawn out of the reference route according to the amount of overlap between the routes; and
(C) A shift process for shifting the position of the other route in the width direction with respect to the reference route so as to realize the set display width is performed, and map drawing data for drawing the route is generated. Process,
It can comprise as a map drawing data generation method provided with.
According to the present invention, the display width can be changed according to the overlap amount. An example of a shift is to shift the route in the width direction from the position where the route originally exists on the map.As a result of the shift, the shifted route shows the width drawn out of the reference route and the width. say. Rather than using a uniform value for this display width, it is possible to avoid unnecessarily large dislocations by changing according to the amount of overlap, and drawing a map while suppressing deviation from the actual state Map drawing data can be generated. And if this map drawing data is used, the map which suppressed the deviation from an actual state and improved the visibility of a route can be drawn.
A route is a general term for roads and railways. Examples of overlapping routes include roads, railroads, roads and railroads.
The reference route may be instructed by the operator, or the higher-priority side may be selected based on the preset importance of the route. For example, it can be a railway, a highway, a national road, a prefectural road, a general road, etc. in descending order of importance.
As the show width, a stepwise value set in advance may be used, or a value calculated according to the positional relationship between the routes.
As the relationship between the show width and the distance between the lines, for example, the show width can be set according to the distance between the center line of the reference route and the center line of the route to be shifted, and the interval is small. In some cases, the display width can be set small, and when the interval is large, the display width can be set large. The interval is the distance between the center lines of the routes. In other words, this is a setting in which the show width is small when the distance between routes is small (in other words, when there is a lot of overlap), and is large when the distance is large (that is, when the overlap is small). If only the visibility is taken into consideration, a uniform display width may be used even when the overlap is large. However, if the overlap is large by taking the above-described mode, the actual state, that is, the overlap is achieved. The visibility of the route on the hidden side can be improved while expressing the state.
The map drawing data includes various types of data such as data for display on a display such as a computer and data for printing on a medium.

In the present invention,
The step (c) may determine the position of the route for each section of the route and perform the dislocation for each section.
By doing so, when a part of the route overlaps, only that section can be shifted. In addition, when the overlap is different for each section, the width of the display can be made different for each section. As a result, unnecessary dislocation can be avoided and deviation from the actual state can be suppressed.
In the above-described aspect, it is preferable that the dislocated section, the other sections, and the sections having different appearance widths are appropriately combined with a smooth curve such as a spline.
The section is not limited to a section having a predetermined length set in advance, and the section can be arbitrarily set according to the overlapping state. For example, a method can be used in which a sequence of points constituting a route is obtained, and the width is determined for each point. In this case, when the density of the point sequence is biased, a resampling process for setting the point sequence with a substantially uniform density along the route may be performed as a pre-process.

In the case of rearrangement for each section, the step (c)
Whether or not to shift the route according to the overlap of the occupied area having a width corresponding to the width of the reference line from the center line of the reference route and the other route, in order from the smallest width of the occupied region. It is a process of judging,
The dislocation is a first condition that the dislocation of the other route is not within the section of the other route, and the center line of the reference route extends beyond the first predetermined length. You may make it carry out about the part which satisfy | fills the 2nd condition located in either one of both sides of.
In this aspect, by determining the occupied area in advance and determining the section to be translocated in accordance with the occupancy area, it is possible to realize dislocation with a different width for each section. The occupied area is a virtual area on the process used for determining whether or not the route is shifted as described above. The overlap between the occupied area and the other route can be determined, for example, by determining whether the center line of the other route is within the occupied region.
In this process, in the above aspect, it is a condition that the route on the dislocation side exists on one of the both sides of the center line of the reference route over the first predetermined length or more. By doing this, for example, the case where the route to be shifted meanders so as to frequently intersect the center line of the reference route can be excluded from the shift target, and the influence of the shift on the route shape can be suppressed. it can.
The first predetermined length can be set to an arbitrary value in order to avoid the meandering portion from being easily subjected to the dislocation, but for example, based on the line width of the route on the dislocation side It can be determined and can be about 2 to 3 times that.
As an alternative condition to the above condition, the dislocation may be a condition in which the dislocation is continued over the first predetermined length in the occupied area in the section where the dislocation is not performed on the other route. good. Moreover, you may use properly the conditions in the said aspect, and alternative conditions according to the line | wire width of a route.

In the above aspect,
In the step (c), the dislocation is performed on a portion that satisfies the third condition that does not satisfy the second condition over a second predetermined length among the portions that satisfy the first condition. Also good.
According to this aspect, when the portion that is not subject to dislocation is equal to or longer than the second predetermined length, it can be subject to dislocation. Therefore, it is possible to avoid a long section and a portion that remains hidden without being dislocated.
The second predetermined length serving as a reference for whether or not to shift the position can be set to a value sufficiently larger than the maximum value of the line width of the route drawn in the map, for example, about 5 times. By doing so, it is possible to avoid unnecessary dislocation of the part where the other lines are merely orthogonal.

In the present invention,
(D) Of the other route, a route that is hidden by the reference route at the end of the drawing range for drawing the map, and a route that is hidden by the reference route at a predetermined ratio or more of the total length of the other route One or both of the above may be provided with a step of performing dislocation unconditionally.
If the other route is hidden by the reference route at the end of the drawing range, it will not be possible to determine whether there is a hidden route at that point, but it can be easily recognized by shifting the route. Will be able to. The end of the drawing range can be the end of the range that is actually printed or displayed, for example, when the map is printed or drawn on a display or the like.
Similarly, when the other route is hidden by the reference route at a predetermined percentage or more of the total length, if most of the route is hidden, not only the shape and connection but also the existence of it will not be able to be grasped. Such a problem can be avoided by dislocation. This processing may be applied only to a route in which the total length of the other route is equal to or less than a third predetermined value that can be arbitrarily set.
The dislocation in the step (d) described above can be performed in various modes. For example, the dislocation corresponding to the minimum display width in other processing may be performed in the sense of suppressing deviation from reality. Further, the dislocation in the step (d) may be performed as post-processing after performing other dislocation processing, or may be performed in parallel with pre-processing or other processing.

The present invention is applicable even when three or more routes overlap.
For example, in the state where there are two or more routes other than the reference route on at least one side of both sides of the center line of the reference route,
The step (b) and the step (c) may be performed in order from a route adjacent to the reference route.
As described above, when there are two or more routes other than the reference route, various methods such as a method of applying the order of the importance of the route and a method of applying at random are considered as the order of performing the dislocation process. However, depending on the method, when a dislocation process is performed on a route, an inappropriate result may occur, such as the positional relationship between the routes being reversed or the route after the dislocation being completely hidden. According to the above aspect, since the dislocation process is performed in order from the route close to the reference route, it is possible to suppress such an inappropriate result.

If more than 3 routes overlap,
(E) When a dislocation process is performed on the route that exceeds another route located outside the route with respect to the reference route, the dislocation treatment is performed on the route on the side beyond the route. It may be provided with a step of shifting to the outside of the line position.
When three or more routes overlap, dislocation processing may be performed in a state where other routes exist outside, and depending on the result, the dislocation processing may be performed in a manner that exceeds other routes. Sometimes. In such a dislocation portion, the positional relationship between the two routes is reversed before and after the dislocation process, which is different from the reality. According to the above-described aspect, when such a dislocation occurs, the dislocation for eliminating the dislocation can be performed, so that a deviation from the reality can be avoided.

If more than two routes overlap,
It is preferable that at least one of the show width in the step (b) and the shift amount in the step (c) is determined based on the result of the processed dislocation treatment.
By doing so, it is possible to avoid a state where the processed route is completely hidden. For example, when setting the display width and shift amount of the next route to be processed, various methods such as a method that considers the position of a route that has been subjected to the dislocation process, and a method that considers the shift amount in the previous shift process can be used. it can. Further, only the dislocation process performed immediately before may be considered, or all previous dislocation processes may be considered.

If more than 3 routes overlap,
In the steps (b) and (c), the importance based on a predetermined criterion is set between a route to be subjected to the dislocation process and a route adjacent to the reference route outside the route. In comparison, the dislocation processing method may be switched based on the importance relationship.
In a region where a plurality of routes overlap, it is difficult to draw all the routes with the original line width, and it is necessary to change the line width drawn by the routes. For example, in order to increase the convenience of the map, it is preferable to increase the line width of routes with high importance, and when dislocation processing is performed in an area where routes overlap, the display width of routes with high importance is sufficient. It is preferable to take a method ensured by As described above, the map is preferably drawn in a manner that reflects the importance of the route. According to the above aspect, the method of dislocation processing can be switched between a case where a low importance route exists outside a high importance route and a reverse case. Therefore, for example, it is possible to realize map drawing reflecting the importance of the route, such as performing a dislocation process that can sufficiently secure the line width of the route with high importance.
Here, the importance of the route can be set by various methods. For example, a method in which the operator sets the importance of each route in advance, a method for determining the importance for each route based on the road type such as a national or prefectural road, and the importance is determined by the number of lanes or the width of each route. The method etc. are mentioned. The importance may be set by combining these methods.

The present invention does not have to include all of the above-described features, and can be configured by omitting or combining a part as appropriate.
The present invention may be configured as a map printing method or a map printing apparatus that prints a map using the map drawing data generated by the above-described method.
The map drawing data generation method of the present invention may be configured as a method automatically executed by a computer. Moreover, you may comprise as a map drawing data production | generation apparatus which produces | generates the map drawing data for drawing a map with the above-mentioned method.
You may comprise as a computer program for making a computer perform the above-mentioned map drawing or the production | generation of map data, and a computer-readable recording medium which recorded this computer program. Recording media include flexible disks, CD-ROMs, magneto-optical disks, IC cards, ROM cartridges, punch cards, printed matter printed with codes such as bar codes, computer internal storage devices (memory such as RAM and ROM), and Various media that can be read by a computer, such as an external storage device, can be used.

It is explanatory drawing which shows the structure of a map drawing apparatus. It is a flowchart of map drawing data generation processing. It is explanatory drawing which shows process target road selection conditions. It is explanatory drawing which shows an occupation area width. It is explanatory drawing which shows the example of a dislocation process by condition C1. It is explanatory drawing which shows the example of a dislocation process by condition C2. It is explanatory drawing which shows an example of a half dislocation and all the dislocation processing. It is explanatory drawing which shows the specific process example (1). It is explanatory drawing which shows the specific process example (2). It is explanatory drawing which shows the specific process example (3). It is explanatory drawing which shows the comparative example before and behind a process. It is explanatory drawing which shows the example of post-processing. It is explanatory drawing which shows the transposition processing method between three roads. It is explanatory drawing which shows the setting method of a processing area. 10 is a flowchart of map drawing data generation processing in the second embodiment. It is a flowchart of a dislocation process (multi). It is explanatory drawing which shows the setting method of dislocation mode. 5 is a flowchart of a dislocation mode 1. It is a flowchart of dislocation mode 2. It is a flowchart of dislocation modes 3 and 4. It is a flowchart of a positional relationship repair process. It is explanatory drawing which shows the process example of the dislocation mode 4. FIG. It is explanatory drawing which shows the process example of the dislocation mode 3. FIG. It is a flowchart (1) of map drawing data generation processing of a modification. It is a flowchart (2) of map drawing data generation processing of a modification.

A. System configuration:
FIG. 1 is an explanatory diagram showing the configuration of the map drawing apparatus. The apparatus of this embodiment is configured by installing a computer program for realizing each function shown in a personal computer and other computers having a CPU, a RAM as a memory, and a ROM. The map can be drawn by a method such as display on a computer display or printing with a printer.
The map drawing apparatus includes a map database 120 and a map drawing database 130. The map database 120 stores, as map data, polyline data and polygon data representing the shape of the feature, etc., and the attribute of the feature, and stores route data representing the position and shape of the route. The data stored in the map database 120 accurately records the position and shape of each feature without considering that the features overlap and hide at the time of drawing. On the other hand, the map drawing database 130 stores polyline data and polygon data obtained by correcting a part of the data in the map database 120 for use in display. In this embodiment, when roads such as roads and railways overlap each other, a shift process is performed to shift one line in the width direction of the other line with respect to the other line, thereby suppressing the state where the line is hidden. ing. The data corrected in this way is stored in the map drawing database 130 as map drawing data. In the present embodiment, the map drawing database 130 stores only the route portion that has been subjected to the shift process, but it may store all the data of features that are not subjected to the shift process.

  The map drawing unit 140 draws a map with reference to the map drawing database 130 and the map database 120. Examples of map drawing methods include display on a computer display and printing on a print medium such as paper.

The map drawing data generation unit 100 performs a process of performing a transposition process on the map data stored in the map database 120 to generate map drawing data and storing it in the map drawing database 130. The process executed by the map drawing data generation unit 100 corresponds to a map drawing data generation method, and the map drawing data generation unit 100 constitutes a map drawing data generation device.
The map drawing data generation unit 100 includes a resampling processing unit 102, a shift processing unit 104, and a post-processing unit 106 in order to perform route transfer processing.
The resampling processing unit 102 arranges the intervals so that the density of the point sequences constituting the route stored in the map database 120 is equal to or higher than a predetermined value. The shift processing unit 104 executes a shift process for shifting the map data representing the route in the width direction. The post-processing unit 106 performs a dislocation process as a post-process on a portion that has not been dislocated by the dislocation processing unit 104 under a predetermined condition. The details of each of these processes will be described later.

The command input unit 110 inputs an instruction necessary for processing to the map drawing data generation unit 100 and the map drawing unit 140 through an operator's operation.
In the present embodiment, the map drawing data generation process executed by the map drawing data generation unit 100 is described as being automatically executed by a computer. However, this process is executed manually in response to an operator instruction. It may be a thing. In such a case, the command input unit 110 also inputs instructions necessary for processing for generating map drawing data.

B. Map drawing data generation process (in case of overlap between two):
Next, the contents of the map drawing data generation process when two roads overlap each other are shown. First, after describing the flow of the entire process, individual processes will be described based on specific examples.
FIG. 2 is a flowchart of map drawing data generation processing. This process corresponds to the function of the map drawing data generation unit 100.
The CPU selects a processing target road (step S10). The processing target road is a road drawn overlapping on a map, such as an elevated road or a road running in parallel. In the present embodiment, a road that satisfies the processing target road selection condition shown in FIG. 3 is further selected.

FIG. 3 is an explanatory diagram showing processing target road selection conditions. A road that satisfies all of the conditions a to d shown on the left side is a processing target road.
The condition a is a condition of “low importance road”. The importance can be arbitrarily set. For example, it can be an expressway, a national road, a prefectural road, a general road, etc. in descending order of importance. When a railway is added as a target, it may be positioned as having a higher importance than these.
The condition b is a condition “a section in which the entire road with high importance is drawn”. This means that the road with the higher importance is at the top in the drawing order, and the side with the higher importance is not hidden by other features and is drawn as a whole. Hereinafter, a road having a high degree of importance is sometimes referred to as a “reference road”.
The condition c is “WL−WH <WV1”. WL is the line width of a road with low importance, and WH is the line width of a road with high importance. WV1 means the minimum display width. The show width is a line width that should be ensured so that the road on the side to be hidden can be visually recognized at the time of drawing, and the amount is changed according to the stage of dislocation. The line width is the width at the time of drawing the road, and does not necessarily match the actual width of the road and the number of lanes. The minimum visible width is a line width that should be secured at least so that the road on the hidden side can be visually recognized at the time of drawing. The minimum display width can be arbitrarily set.
An example of determining condition c is shown in the upper right side. The hatched side is a low priority road, and the line width is 20 points. The white side is a high priority road, and the line width is 15 points. Therefore, WL-WH = 5. If “minimum showing width WV1 = 5” is set, condition c is not satisfied, and if “WV1 = 6” is set, condition c is satisfied. As described above, the condition c is that the line width (WL) of the road with low importance is greater than the line width (WH) of the road with high importance, which is equal to or larger than the minimum display width WV1. It means to remove. In such a case, a road with low importance can be sufficiently visually recognized, and there is no need to perform a dislocation process.
The condition d is “WL> WV1”. That is, the line width (WL) of a road with low priority is larger than the minimum appearance width (WV1). An example of judgment is shown on the lower right side. Assuming that the minimum visible width WV1 = 5 points, the condition d is not established if the road width of the low-priority road (hatched side) is 3 points, and the condition d is established if the line width is 6 points. Become. The line width of a road with high importance (outlined) is irrelevant to the condition d. This is because, when the line width of a road with low priority is smaller than the minimum display width, the minimum display width cannot be secured even if the entire road is drawn.
In the embodiment, the one that satisfies all of the conditions a to d is selected, but the one that satisfies a part may be selected. Further, the processing target road selection condition may omit some of the above-described conditions, or may add other conditions.

When the processing target road is selected, the CPU performs a resampling process (step S11 in FIG. 2). The resampling process is a process of adjusting the interval so that the density of the point sequences constituting the route stored in the map database 120 is equal to or higher than a predetermined value.
An example of processing is shown in the figure. It is assumed that the route is represented by a point sequence including a plurality of constituent points indicated by black circles. In the section D1 between the configuration points P1 and P2 and the section D2 between the configuration points P3 and P4, the density of the configuration points is low. In the resampling process, the configuration points PA1 to PA3 are newly added at such locations, and the density of the configuration points is set to a predetermined value or more.
Here, the density of the constituent points can be set, for example, under the condition that “the distance between the constituent points is a predetermined value or less”. The resampling process is a method for determining a position of a new component point by identifying a portion that does not satisfy the above-mentioned density-related requirements and dividing the section into two equal parts, three equal parts, etc., until the requirements are satisfied. Can take. The section D2 in the figure is an example in which the constituent point PA3 is set by dividing into two equal parts, and the section D1 is divided into three equal parts and the constituent points PA1 and PA2 are set.
In the present embodiment, the occupancy area is changed in three stages and the dislocation process is performed in units of constituent points after the resampling process.

  In order to execute the dislocation process, the CPU sets an occupied area (step S12). The occupied area is an area formed by providing a predetermined width on both sides from the center line of the reference road, and is an area for determining whether or not each constituent point is a shift target. In the present embodiment, this process is executed by changing the occupation area in three stages while increasing the occupation area in order. The first dislocation process is called “fine dislocation”, the second “half dislocation”, and the third “full dislocation”.

FIG. 4 is an explanatory diagram showing a predetermined width, that is, an occupied area width in each dislocation process.
· Fine dislocation 4 for (a) shows the occupied area width in fine dislocations. The half width WC1 of the occupied area is determined by the following equation.
WC1 = (WH−WL) / 2 + WV1;
WH: Line width of road (reference road) with high importance;
WL: Line width of less important roads;
WV1: Minimum viewing width (3 points in this embodiment);
A width WC1 indicated by a broken line in the figure is a half width of the occupied area. When the center line of the less important road R1 is shifted to the boundary of the occupied area as indicated by the arrow A, the road R1a protrudes by the width of WV1 from the reference road. In the figure, in order to avoid complication of the figure, a state of being shifted obliquely with respect to the width direction of the road is shown (arrow A). However, in actual shift processing, the road R1 is moved in the width direction. Translated.
- Figure 4 (b) for a semi-dislocation shows the occupied area width at half dislocation. The half width WC2 of the occupied area is determined by the following equation.
WC2 = (WH−WL) / 2 + WV2;
WV2: width at half dislocation (in this example, WL / 2);
A width WC2 indicated by a broken line in the figure is a half width of the occupied area. When the center line of the less important road R1 is shifted to the boundary of the occupied area as indicated by the arrow B, the road R1b protrudes by the width of WV2 from the reference road.
-About all dislocations FIG.4 (c) has shown the occupied area width in all the dislocations. The half width WC3 of the occupied area is determined by the following equation.
WC3 = (WH + WL) / 2;
A width WC3 indicated by a broken line in the figure is a half width of the occupied area. When the center line of the less important road R1 is shifted to the boundary of the occupied area as shown by the arrow C, the entire less important road protrudes as shown by the road R1c.

When the occupied area is set in this way, the CPU scores each constituent point that has not been dislocated (step S13 in FIG. 2). The score is defined as an absolute value of 2 for the constituent points in the occupied area, an absolute value of 1 for the constituent points outside the occupied area, and a negative value on the left side of the center line and a positive value on the right side. Since the scoring is applied to undislocated constituent points, all constituent points are targeted during the first fine dislocation processing, and constituent points that were not dislocated in the previous processing are subject to the second and subsequent processing.
The CPU determines a dislocation target constituent point using the number of points assigned in this way (step S14). In order to be a dislocation target constituent point, it is necessary to satisfy the following condition C1 or condition C2.
(Condition C1) | Total value of three points before and after |> 3 and within the occupying area and predetermined within one of the two occupying areas divided by the center line of the reference route Continuous for a distance L1 or more;
(Condition C2) The non-dislocation target constituent points that are constituent points that do not satisfy the condition C1 are continuous for a predetermined distance L2 or more in the occupied region;
Note that the condition C1 may be, for example, a condition that the constituent points are | the total value of the three points before and after |> 3 and continue for a predetermined distance L1 or more in the occupied area.
Hereinafter, the content of the determination process of the dislocation target composing point is shown based on a specific example.

FIG. 5 is an explanatory diagram showing an example of a dislocation process under the condition C1. An occupied area is set around the center line CL of the reference road. In the portion where the reference road is curved, the center line and the occupied area are also set to be curved. Further, the area AR1 outside the occupied area located on the left side in the traveling direction of this road is -1 point, the area AR2 inside the occupied area is -2 points, and the area AR3 inside the occupied area located on the right side in the traveling direction is two points occupied. The area AR4 outside the area is assigned one point and a score.
Black circles P [1] to P [13] in the figure are constituent points of the road on the less important side. In accordance with the areas AR1 to AR4 to which each constituent point belongs, the score is determined as shown in the score column in the figure. In the condition C1, the total value of the three points before and after is obtained as the evaluation score. As for the constituent point P [1], since there is no previous constituent point, -4 points which are the total points of the constituent points P [1], P [1] and P [2] are the evaluation points. For the component point P [2], -1 point, which is the total of the component points P [1] to P [3], is the evaluation score. Similarly, the evaluation points shown in the figure are obtained for the other constituent points.
Then, a configuration point whose absolute value of the evaluation score is greater than 3 is selected. In the example in the figure, the configuration points P [1], P [4], P [5], P [8], P [9], P [10], and P [11] are selected.
The condition C1 is a condition that a line connecting the three front and rear constituent points does not intersect the center line of the reference road. As described above, instead of the method of evaluating by the score, it may be directly analyzed whether or not it intersects with the center line. In this way, by identifying the location where the line connecting the three front and rear constituent points intersects the center line of the reference road and removing it from the target of dislocation, the dislocation result becomes smooth and the appearance is improved.

In the condition C1, not only the determination based on the above-mentioned evaluation score, but also “a predetermined distance within one of the two areas of the occupied area and the occupied area divided by the center line of the reference route” L1 (corresponding to the first predetermined length) or more "is also a condition. The configuration points P [1], P [5], and P [10] do not satisfy this condition. If the distance between the constituent points P [8] and P [9] is equal to or greater than the predetermined distance L1, this condition is satisfied, so that the constituent points are dislocation target constituent points. In this figure, white dots are added to the constituent points P [8] and P [9] in this sense.
The predetermined distance L1 is set to avoid a meandering portion from being easily subjected to a dislocation, and can be set to an arbitrary value. For example, the line width of the road on the dislocation side can be about 2 to 3 times the standard.

FIG. 6 is an explanatory diagram showing an example of a dislocation process under the condition C2. The condition C2 is a condition that “a non-dislocation target constituent point that is a constituent point that does not satisfy the condition C1 is continuous for a predetermined distance L2 (corresponding to a second predetermined length) in the occupied region”. This is because, as shown in the region BB in the figure, when the non-dislocation target constituent points are continuous over a long section, the portion where the less important road RDB is hidden by the reference road RDC becomes longer, and the shape and connection condition are longer. It is a condition for avoiding that it becomes impossible to grasp.
Accordingly, the predetermined distance L2 (corresponding to the second predetermined length) can be set to a value sufficiently larger than the maximum value of the road line width, for example, about five times. By doing so, for example, it is possible to avoid unnecessary shift of the portion AA in which the other road RDA is only substantially orthogonal to the reference road RDC.

When the dislocation target composing points are determined in this way, the CPU displaces these dislocation target composing points to the boundary of the occupied area (step S15 in FIG. 2). The shift is performed by a method of translating each component point in a direction orthogonal to the center line of the reference road. The component point located on the left side of the center line is moved to the left boundary and to the right boundary located on the right side.
The CPU repeats the above process three times for fine dislocation, half dislocation, and total dislocation (step S16), and ends the dislocation processing.

FIG. 7 is an explanatory diagram showing an example of the half-dislocation and all-dislocation processing. As shown in FIG. 7A, an example of processing for a portion where a reference road and a less important road are drawn to overlap is shown.
FIG. 7B shows an example of half-dislocation processing. At this point, some constituent points have been dislocated by the process of fine dislocation. In the case of half dislocation, processing is performed in the same procedure as shown in FIGS. First, the CPU sets a semi-dislocation occupied area for the road center line CL1. Then, a score is assigned to each component point that defines the center line CL2 of the road with low importance. In FIG. 7B, points inside the occupied area are indicated by black circles, and points outside the area are indicated by x.
When the CPU obtains an evaluation score (see FIG. 5) for each of these constituent points and finds constituent points that are continuous for a predetermined distance L1 or more in the occupied area, the dislocation target constituent points (configurations with white circles in the figure) Point, corresponding to the picture area PP1 in the figure). The predetermined distance L1 may be a value different from that at the time of fine dislocation processing. Each dislocation target composing point set in this way is dislocated to the boundary line of the semi-dislocation occupied region.
FIG. 7C shows a processing example of all dislocations. The constituent points that have been rearranged by the process up to the half dislocation (corresponding to the region PP1 in FIG. 7B) are indicated by large black circles. In this process, other constituent points are processed. The CPU sets an occupied area for all dislocations for the road center line CL1. Then, a score is assigned to each component point that defines the center line CL3 of the road with low importance. In FIG. 7C, points within the occupied area are indicated by black circles and points outside the area are indicated by x.
When the CPU obtains an evaluation score (see FIG. 5) for each of these constituent points and obtains constituent points that are continuous for a predetermined distance L1 or more, the CPU determines the dislocation target constituent points (the constituent points with white circles in the figure, in the figure). Corresponding to PP2). The predetermined distance L1 may be a value different from that at the time of fine dislocation processing. Each dislocation target composing point set in this way is dislocated to the boundary line of the occupied area of all dislocations.
FIG. 7D shows a specific example of the dislocation process. Assume that the constituent points PB [1] to PB [3] shown in FIG. At the time of shift, the CPU obtains perpendicular lines M [1] to M [3] that pass through the respective constituent points with respect to the center line CL1 of the reference road. Then, constituent points PA [1] to PA [3] after dislocation are set at the intersections between the respective perpendicular lines and the boundary lines of the occupied areas. The shift is performed on the boundary side located on the same side as the composing point with respect to the center line of the reference road. In the example shown in the figure, since all the constituent points are located below the center line CL1, they are shifted to the lower boundary. If there is a composing point located above the center line CL1, it is transferred to the upper boundary.

C. Processing example:
Specific processing examples according to the above processing procedure are shown in FIGS.
FIG. 8A shows the state of the road before processing. As shown in the figure, a road with low importance is drawn hidden behind the reference road, and there is a portion where the shape and connection cannot be grasped.
FIG. 8B shows the dislocation process progress of fine dislocations. In order to avoid complication of the figure, the outline of each road is omitted. The CPU sets an area occupied by fine dislocations on the center line CL1 of the reference road. (See FIG. 4 (a)). Based on this occupied area, the CPU evaluates the score for each constituent point of the road center line CL2 of low importance. Points within the occupied area are indicated by black circles, and points outside the area are indicated by x. In addition, white dots are added to the points to be dislocations.
FIG. 8C shows a state in which dislocation processing is performed on these points according to a command from the CPU. As a result, the dislocation target composing points are each dislocated to the boundary of the microdislocation occupation region. The point after dislocation is indicated by a large black circle.

FIG. 9A shows the transition process of half dislocation. On the center line CL1 of the reference road, a semi-dislocation occupied area is set by the CPU (see FIG. 4B). Based on this occupied area, the CPU evaluates the score for each constituent point of the center line CL3 of the road with low importance. Points within the occupied area are indicated by black circles, and points outside the area are indicated by x. In addition, among the constituent points not subjected to fine dislocations, the points to be dislocations are shown with white circles.
FIG. 9B shows a state in which a semi-dislocation process is performed on these points according to a command from the CPU. As a result, the dislocation target composing points are each dislocated to the boundary of the half-dislocation occupied region.

FIG. 10A shows the dislocation process progress of all dislocations. On the center line CL1 of the reference road, an occupied area of all dislocations is set by the CPU (see FIG. 4C). Based on this occupied area, the CPU evaluates the score for each constituent point of the low-importance road center line CL4. Points within the occupied area are indicated by black circles, and points outside the area are indicated by x. In addition, among the constituent points that have not been subjected to fine dislocations or half dislocations, the points to be dislocations are indicated by white circles.
FIG. 10B shows a state in which all the dislocation processing has been performed on these points in accordance with instructions from the CPU. As a result, the dislocation target composing points are each dislocated to the boundary of the occupied region of all dislocations.

FIG. 11 is an explanatory diagram illustrating a comparative example before and after processing. FIG. 11A shows a state before processing, FIG. 11B shows a state where fine dislocation has been completed, and FIG. 11C shows a state where half dislocation and all dislocation processing have been completed.
As described above, according to the rearrangement process of the present embodiment, a road having a low importance appears, and the shape and connection state can be grasped. Further, by using a three-stage occupied area of fine dislocations, half dislocations, and all dislocations in combination, deviation from the actual state can be suppressed.

D. Post-processing:
FIG. 12 is an explanatory diagram illustrating an example of post-processing. This is a process targeting a portion that has not been dislocated by the dislocation process described with reference to FIGS.
FIG. 12A shows an example of processing in a map frame. As shown on the left side, if there is a place where a road with low importance in the point reaching the picture frame is hidden in the reference road, the CPU unconditionally performs a dislocation process of fine dislocation as shown on the right side. The reason for the slight dislocation is to prevent the dislocation from the actual state due to excessive dislocation. By shifting the position at the point reaching the picture frame in this way, it can be easily recognized that there is a road of low importance, and the user can easily collate the map between the different picture frames.
FIG. 12B shows the process when the total road length is short. The left side shows the state before processing. A road with low importance is hidden in the reference road, but in the above-described shift process, only when the road is continuous for a predetermined length or longer (see step S14 in FIG. 2), the total length of the road is short. Is not subjected to dislocation treatment. For the short roads, if most of them are hidden, not only the shape and connection, but even the existence of them can not be grasped. In the example in the figure, it is a dead end on the way or it is connected to the road on the right side at all I do not understand. Therefore, in the post-processing, if a predetermined percentage of the road (70% in this embodiment) or more is hidden, the CPU unconditionally performs fine dislocation. The right side shows the state after processing. By doing so, the existence of a short road can be easily grasped, and the shape and connection can be recognized.

E. effect:
According to the shift process described above, the road hidden behind the reference road can be drawn in a visually recognizable state. At this time, the divergence from the actual state can be suppressed by changing the occupied region of fine dislocations, half dislocations, and all dislocations in a plurality of stages and obtaining the dislocation amount. The shift amount represents an amount of shifting the processing target road in the width direction of the reference road by the shift process.

  As Example 2, an example in which a dislocation process is performed between three or more roads will be described. The configuration of the map drawing apparatus for realizing such a rearrangement process is the same as that of the first embodiment (FIG. 1). Hereinafter, a dislocation processing method according to the second embodiment will be described by taking a dislocation process between three roads as an example.

F. Dislocation treatment method:
FIG. 13 is an explanatory diagram showing a shift processing method between three roads. The rearrangement process is performed by a method of rearranging another road with respect to the reference road, as in the first embodiment. The reference road is the road with the highest importance. There are three possible arrangements of roads other than the reference road as shown in FIGS. 13 (a) to 13 (c).
FIG. 13A shows an example in which there are other roads on both sides of the reference road. In the example of the figure, the case where the road on the upper side of the reference road is more important than the road on the lower side is illustrated, but the opposite may be possible. The description of high importance and low importance in the figure represents the high and low importance of two roads other than the reference road. In such an arrangement, the roads on both sides are shifted outward as indicated by arrows a1 and a2. Outside means the direction away from the reference road. In this arrangement, if it is divided into the upper and lower areas with the center line of the reference road as a boundary, it is a shift process between two (reference road and one other road). The dislocation process described in 1 may be applied.
FIG. 13B shows an example in which two roads exist on the one side of the reference road from the inside in the order of high importance and low importance. In such an arrangement, the high importance road on the inside is shifted outward as indicated by arrow b1, and the low importance road located on the outside is shifted outward as indicated by arrow b2. However, high-importance roads are rearranged to ensure a wider appearance width than low-importance roads. On the other hand, the low importance road is shifted so that it does not enter the high importance road and is not hidden by the high importance road. “Do not enter the inside of a road with high importance” means that the position is shifted so that the positional relationship between high importance and low importance does not reverse from the inside. Detailed dislocation processing for determining the dislocation amount of each road will be described later.
FIG. 13C shows an example in which two roads exist on the one side of the reference road from the inside in the order of low importance and high importance. Also in such an arrangement, first, a low importance road inside is shifted to the outside as indicated by an arrow c1, and then a high importance road located outside is shifted to the outside as indicated by an arrow c2. However, for low-importance roads, rearrangement will be made to ensure a minimum width. High-importance roads are shifted so that they do not enter inside of low-importance roads, do not hide low-importance roads, and ensure a sufficient width.
The processing of FIGS. 13A to 13C is performed for each processing region by dividing each road into processing regions according to their arrangement.

FIG. 14 is an explanatory diagram illustrating a method for setting a processing area. As an example, a highway, a national road, a prefectural road, and a general road are running close to each other. The importance of the road is assumed to be in the order of highway> national road> prefectural road> general road.
In the area A, the highway and the national road are close to each other, so that the dislocation process between the two is performed. General roads are sufficiently spaced from national roads, so there is no need for dislocation treatment. Whether or not the shift process is necessary can be determined based on whether or not the distance between the roads is equal to or less than a predetermined value. If there are many roads to which dislocation processing is performed, the result of dislocation processing may be close to other roads that are sufficiently spaced before the dislocation. It is preferable to set the determination criterion of “no” to a value having a sufficient margin.
In the area A, a highway having a high degree of importance becomes a reference road, and a transition process is performed on the national road on the basis of this. In the present embodiment, as shown in the figure, the reference road is divided into a right region and a left region with respect to the traveling direction a, and a dislocation process is performed for each region. In each of the right region and the left region, the national road is shifted in a direction away from the highway that is the reference road (also referred to as the outer direction), as indicated by the white arrows.
Area B is an area where the national road and the general road are relatively close to each other. Therefore, in this area, a dislocation process is performed between the three roads: the highway, the national road, and the general road. In this area, a high-priority expressway is a reference road, and is arranged in the order of a national road and a general road in the area on the left side in the traveling direction b. This arrangement is more important than the general road where the state shown in FIG. 13B, that is, the national road that is a road close to the reference road (also referred to as an inner road) is a distant road (also referred to as an outer road). Therefore, the dislocation is performed by the method described in FIG.
In the region C, the highway is not an object of the dislocation process because the highway and the national road are spaced apart. Therefore, in this area, a dislocation process between the two is performed between the national road and the general road. National roads with high importance are standard roads. Since the general road is located in the left area in the traveling direction c of the national road, the dislocation process is performed in the left area, and the dislocation process is not performed in the right area.
In the region D, a dislocation process is performed between three roads, a national road, a general road, and a prefectural road. Among these three, the national road with the highest importance is the reference road, and is arranged in the order of the general road and the prefectural road in the left region of the traveling direction d. Such an arrangement is illustrated in FIG. 13C because the state shown in FIG. 13C, that is, the ordinary road that is the inner road is less important than the prefectural road that is the outer road. The dislocation is performed by the method. In the right area, dislocation processing is not performed.

G. Map drawing data generation processing:
Processing contents for realizing the shift between the three or more roads described in FIGS. 13 and 14 will be described.
FIG. 15 is a flowchart of map drawing data generation processing in the second embodiment. When the process is started, the CPU sets a processing area based on the interval between the roads (step S100). This corresponds to the processing described in FIG. Roads having an interval between roads equal to or smaller than a predetermined value are included in the same processing area, and the number and names of roads included in one set processing area do not change throughout the processing. As shown in FIG. 14, even on a single road called a national road, processing areas are set separately for each section in which roads to be subjected to shift processing are different.

Next, the CPU selects one of the processing areas and cuts out a section in the processing area for each road (step S102). Then, the road with the highest importance in the processing area is selected as the reference road (step S104).
Since the shift process is performed separately for the right area and the left area of the reference road, the CPU first determines the shift process mode for the right area (step S106). As shown in FIG. 13 (a), when a shift is performed between two roads, a shift process (two) is executed (steps S106 and S9). As the dislocation process (two), the map drawing data generation process (FIG. 2) described in the first embodiment is applied. As shown in FIGS. 13B and 13C, when a shift is performed between three roads, a shift process (multi) is performed (steps S106 and S20). The contents of the dislocation process (multi) will be described later. If there is no overlap with any road, these dislocation processes are skipped.
The CPU performs the above dislocation processing (steps S106, S9, S20) in the same manner for the left region (S110), and completes the dislocation processing for one processing region.
Further, this process is repeated until all the processing areas are completed (step S112), and the map drawing data generation process is completed.

G1. Dislocation processing (multiple):
FIG. 16 is a flowchart of the dislocation process (multi). This is a shift process between three or more roads, and corresponds to step S20 in FIG. This processing is performed for each processing region.
When the process is started, the CPU sets an overlap determination area based on the reference road and the processed road on which the shift process has been performed (step S21). The overlap determination area is an area for determining whether or not to perform a shift process on another road, that is, whether or not the other road overlaps the reference road and the processed road.
An example of setting the overlap determination area is shown in the figure. When there is no processed road, the overlap determination area 1 is determined based on the line width of the reference road. When there is a processed road, the overlap determination area 2 is set based on the maximum line width that covers both the reference road and the processed road.
The purpose of considering the treated road in this way is as follows. As in Example 2, when the shift process was sequentially performed on three or more roads, in a state before the shift, a road that was sufficiently away from the reference road was shifted to another road. As a result, there may be an overlap with the treated road. Therefore, in the second embodiment, as described above, the overlap determination area is set in consideration of the position of the processed road. By doing so, it can be avoided that another road is hidden by the processed road.

CPU detects the process target road which should perform a shift process using the above-mentioned duplication determination area | region (step S22). The conditions for setting the road to be processed are as follows.
Condition 1 is an untreated road condition. This is because there is no need to perform further dislocation treatment on the road that has undergone dislocation treatment.
Condition 2 is that which satisfies the above condition 1 and which is closest to the reference road, that is, inside. By performing the shift process in order from the road closest to the reference road in this way, it is possible to avoid the situation that the process road is hidden by the shift process performed later or the positional relationship is reversed by the shift process. Can do.

As a result of the detection, if there is no processing target road (step S23), the CPU ends the shift process (multi).
If there is a road to be processed (step S23), the shift mode is determined (step S24), and the resampling process similar to that shown in the first embodiment is performed (see step S11 in FIG. 2). The dislocation mode means a method of dislocation processing determined based on the arrangement state according to the importance of the road, as described with reference to FIGS. 13B and 13C. Details of the dislocation mode will be described later.
The CPU performs dislocation in each dislocation mode thus set (step S26), and performs positional relationship repair processing (step S27). The positional relationship repair processing is based on the positional relationship that has deviated from the actual state by shifting the road that has been crossed over the other road when the road to be processed is shifted. It is processing for returning to. Specific processing contents will be described later.
The CPU repeats the above processing for all roads in the processing area (step S28), and ends the shift processing (multi).
Hereinafter, setting of the dislocation mode, processing contents in each dislocation mode, and positional relationship repair processing will be described in order.

G2. Dislocation mode:
FIG. 17 is an explanatory diagram showing a method for setting the dislocation mode. This mode is set in step S24 of the dislocation process (multi) (FIG. 16). In this example, four types of dislocation modes 1 to 4 were set.
The dislocation modes 1 and 2 are modes when there is no outside unprocessed road. In other words, this corresponds to a mode in which the rearrangement process should be performed last after the rearrangement process is performed in order from the inner road close to the reference road. Since the rearrangement process is performed in a state in which no other road exists outside, it is not necessary to emphasize the relationship with other roads. In the shift modes 1 and 2, the shift process is switched depending on the importance relationship between the road to be processed and the road existing inside.
The shift mode 1 is a case where the importance of the processing target road is higher than that of the inner road. This corresponds to the case where the road with the high importance shown in FIG. 13C is processed. In this shift mode, the road to be processed is shifted so as to ensure a sufficient width. In addition, although the minimum width of each road can be set arbitrarily, it is assumed that the following conditions are satisfied.
Importance Inner road <Treatment target road:
0 <WV1 <WO and (WI-WO) / 2 ≦ WV1;
WV1: the minimum width of the road to be treated;
WO: Line width of road to be treated;
WI: inner road line width;
The shift mode 2 is a case where the importance of the processing target road is lower than that of the inner road. This corresponds to the case of processing the low-priority outside road shown in FIG. In this shift mode, the road to be processed is subjected to shift processing so as to ensure a necessary width for viewing. In addition, although the minimum width of each road can be set arbitrarily, it is assumed that the following conditions are satisfied.
Importance Inner road> When the road to be processed:
0 <WV1 <WO and (WO-WI) / 2 ≦ WV1;
Shift modes 3 and 4 are modes when there is an unprocessed road outside. It does not matter whether or not a processed road exists inside the processing target road. In this mode, the shift process is performed in a state where there is another road on the outer side, and therefore the shift process is switched in consideration of the importance relationship between the road to be processed and the outer road. In addition, although the minimum width of each road can be set arbitrarily, it is assumed that the following conditions are satisfied.
Importance Inner road <Treatment target road:
0 <WV1 <WO and (WI-WO) / 2 ≦ WV1;
Importance Inner road> When the road to be processed:
0 <WV1 <WO and (WO-WI) / 2 ≦ WV1;
The shift mode 3 is a case where the importance of the processing target road is higher than that of the outer road. This corresponds to the case of processing the inner road with high importance shown in FIG. In this rearrangement mode, the rearrangement process is performed so that the processing target road has a sufficient width, that is, a wider width than the outer road.
The shift mode 4 is a case where the importance of the processing target road is lower than that of the outer road. This corresponds to the case of processing a low-priority inner road shown in FIG. In this shift mode, the road to be processed is subjected to shift processing so as to ensure a necessary width for viewing.
Hereinafter, the contents of the dislocation process in each dislocation mode will be described.

G3. Dislocation mode 1:
FIG. 18 is a flowchart of the dislocation mode 1. This is one of the processes performed according to the dislocation mode in step S26 of the dislocation process (multi) (FIG. 16).
The CPU first determines whether a dislocation process is necessary (step S30). Here, it is assumed that dislocation processing is necessary when either of the following two conditions is satisfied.
The first condition is that the minimum road width WV1 of the inner road is not secured. This condition can be expressed by the following conditional expression.
DIST-WO / 2 <WV1;
DIST: distance between the road to be processed and the inner road;
WO: Line width of road to be treated;
WV1: Minimum width of the inner road;
When the first condition is satisfied, a dislocation process is necessary to secure the minimum width of the inner road.
The second condition is that the inner road protrudes outside the processing target road. This condition can be expressed by the following conditional expression.
DIST + WO / 2 <WI / 2;
WI: inner road line width;
When the second condition is satisfied, a dislocation process is required to prevent the inner road from protruding.
If it is determined that the dislocation process is unnecessary based on the above conditions, the CPU ends the dislocation mode 1 process as it is.

Next, the CPU sets an occupied area (step S31). In the present embodiment, the width of the occupied area is switched as follows depending on which of the above conditions 1 and 2 is satisfied. The setting of the occupied area is not complete. In order to secure the minimum visible width of the inner road, the occupation area is expanded by the processing shown later.
When the condition 1 is satisfied, the half width of the occupied area is “(WI + WO) / 2”.
This corresponds to an occupied area for shifting the processing target road to a position adjacent to the inner road (see FIG. 4).
When the condition 2 is satisfied, the half width of the occupied area is “(WI−WO) / 2”.
This corresponds to the occupied area width for eliminating the protrusion of the inner road.

  When the occupied area is set in this way, the CPU next performs an expansion process of the occupied area (step S32). The expansion width is the total fine dislocation width for the road that has been subjected to dislocation processing. The total fine dislocation width is the fine dislocation width added together with the dislocation process. For example, when the dislocation process has been completed for one road, the occupation area set in step S31 is expanded by the fine dislocation width used in the dislocation process. If the dislocation process has been completed for two roads, the occupied area set in step S31 is expanded by an amount corresponding to the sum of the fine dislocation widths used in the two dislocation processes. In this way, by expanding the occupied area based on the conventional dislocation process, it is possible to perform the dislocation process while ensuring a show width corresponding to the fine dislocation, that is, a minimum show width, for each road that has been transferred. .

The CPU performs the rearrangement process by transposing the constituent points of the processing target road using the expanded occupied area (step S33). A specific method of this processing is the same as that in the first embodiment.
Further, after the dislocation process, the post-process (exceptional dislocation) shown in the first embodiment (see FIG. 12) is also performed (step S34).

G4. Dislocation mode 2:
FIG. 19 is a flowchart of the dislocation mode 2. This is one of the processes performed according to the dislocation mode in step S26 of the dislocation process (multi) (FIG. 16).
The CPU first determines whether or not a dislocation process is necessary (step S40). Here, it is assumed that dislocation processing is necessary when both of the following two conditions are satisfied.
The first condition is that the processing target road is not visible by the minimum visible width. This condition can be expressed by the following conditional expression.
DIST + WO / 2-WI / 2 <WV1;
DIST: distance between the road to be processed and the inner road;
WO: Line width of road to be treated;
WI: inner road line width;
WV1: the minimum width of the road to be treated;
The second condition is that the line width of the processing target road is thicker than the minimum visible width. This is because if the width is narrower than the minimum display width, the minimum display width cannot be secured even if the dislocation process is performed.
If it is determined that the dislocation process is unnecessary based on the above conditions, the CPU ends the dislocation mode 2 process as it is.

  Next, the CPU sets an occupied area (step S41). In the dislocation mode 2, as in the first embodiment, the occupancy region is changed stepwise by performing the process three times. Therefore, fine dislocation is set in the first process, half dislocation is set in the second process, and the occupied area width of all dislocations is set in the third process. Each occupied area width is as described in the first embodiment (see FIG. 4).

When the occupation area is set in this way, the CPU performs an expansion process of the occupation area as in the case of the dislocation mode 1 (step S42). The expansion width is the total fine dislocation width for the road that has been subjected to dislocation processing. In this way, by expanding the occupied area based on the conventional dislocation process, it is possible to perform the dislocation process while ensuring a show width corresponding to the fine dislocation width, that is, a minimum show width, for each road that has been transferred. it can.
Then, the CPU performs a rearrangement process by rearranging the constituent points of the processing target road using the expanded occupied area (step S43). A specific method of this processing is the same as that in the first embodiment. After repeating the above process three times (step S44), the CPU also performs the post-process (exceptional dislocation) shown in the first embodiment (see FIG. 12) (step S45).

G5. Dislocation mode 3, 4:
FIG. 20 is a flowchart of the dislocation modes 3 and 4. This is one of the processes performed according to the dislocation mode in step S26 of the dislocation process (multi) (FIG. 16).
The CPU first determines whether or not a dislocation process is necessary (step S50). Here, as in the dislocation mode 2, it is assumed that dislocation processing is necessary when both of the following two conditions are satisfied.
The first condition is that the processing target road is not visible by the minimum visible width. This condition can be expressed by the following conditional expression.
DIST + WO / 2-WI / 2 <WV1;
DIST: distance between the road to be processed and the inner road;
WO: Line width of road to be treated;
WV1: Minimum viewing width;
The second condition is that the line width of the processing target road is thicker than the minimum visible width. This is because if the width is narrower than the minimum display width, the minimum display width cannot be secured even if the dislocation process is performed.
When it is determined that the dislocation process is unnecessary based on the above-described conditions, the CPU ends the processes of the dislocation modes 3 and 4 as they are.

Next, the CPU sets an occupied area (step S51).
In the case of the dislocation mode 3, in order to secure a sufficient width for the processing target road, as in the first embodiment, the dislocation width is changed stepwise by performing the process three times. Therefore, the microdislocation is set in the first process, the semi-dislocation is set in the second process, and the occupied area of all the dislocations is set in the third process. The method for setting each occupied area is as described in the first embodiment (see FIG. 4).
In the case of the dislocation mode 4, in order to secure a minimum display width for the processing target road, an occupation area for fine dislocation is set.

When the occupation area is set in this way, the CPU performs the expansion process of the occupation area as in the case of the dislocation mode 1 (step S52). The expansion width is the total fine dislocation width for the road that has been subjected to dislocation processing. In this way, by expanding the occupied area based on the conventional dislocation process, it is possible to perform the dislocation process while ensuring a show width corresponding to the fine dislocation width, that is, a minimum show width, for each road that has been transferred. it can.
Then, the CPU performs a shift process by shifting the constituent points of the processing target road using the expanded occupied area (step S53). A specific method of this processing is the same as that in the first embodiment.
In the case of the dislocation mode 3, the above process is repeated three times (steps S54 and S55), and in the case of the dislocation mode 4, the process is completed once (step S54). When these dislocation processes are completed, the CPU also performs post-processing (exceptional dislocation) (see FIGS. 11 and 12) shown in the first embodiment (step S56).

  In the occupied area expansion (step S32 in FIG. 18, step S42 in FIG. 19, step S53 in FIG. 20) in the dislocation modes 1 to 4 described above, the expansion corresponding to the total fine dislocation width is performed uniformly. Various settings can be made for the expansion width of the occupied area. For example, instead of the total fine dislocation width, the total half-dislocation width and the total total dislocation width may be set, or the expansion width may be changed according to the dislocation mode. If the inner road is less important than the road to be processed, the extension width is the sum of the shift widths according to the shift mode of the inner processed road. The extension width may be changed in accordance with the importance of the processing target road and the inner processed road, such as fine dislocation. As illustrated in various examples, by setting the expansion width to various settings, it is possible to secure the display width of the inner processed road while suppressing the width of the entire road from being strangely widened due to excessive dislocation. It becomes possible.

G6. Positional repair processing:
FIG. 21 is a flowchart of the positional relationship repair process. This is a process corresponding to step S27 of the dislocation process (multi) (FIG. 16). The positional relationship repairing process is a process for repairing the positional relationship by shifting the road on the side that has been crossed when a shift is made across the road located outside.
The CPU extracts from the constituent points of the processing target road, those that have been shifted beyond the outer road in the previous processing (step S60). An example of processing is shown in the figure. It is assumed that the points P1 to P3 indicated by ● have been transferred beyond the outer road as a result of the dislocation processing as indicated by arrows for the constituent points of the processing target road indicated by ○ in the figure. In step S60, the points P1 to P3 are extracted.

  Next, the CPU shifts the constituent points of the outer road that are inside the constituent points extracted in step S60 (step S61). The inside means the reference road side. An example of processing is shown in the figure. Among the constituent points of the outer road indicated by ×, three points inside the points P1 to P3 extracted in step S60 are extracted and rearranged as points q1 to q3. The dislocation here is such that these points q1 to q3 are located outside the outer points P1 to P3. It may be displaced so as to overlap the points P1 to P3, or may be moved further outward. The points q1 to q3 to be transferred are not necessarily the same number as the points P1 to P3 extracted in step S60, and all constituent points existing inside the processing target road are targets.

When the processing target road is shifted beyond the outer road, the portion (points P1 to P3 shown in step S60) means that either the processing target road or the outer road exists inside. The positional relationship will deviate from the reality. The rearrangement in this embodiment is intended to be performed in order to secure the width on the map while avoiding the deviation from the reality, so it is necessary to eliminate such inversion of the positional relationship. is there.
If the above-described shift process is performed, the positional relationship can be restored and the deviation from the reality can be eliminated by further shifting the road outside the positional relationship in this way. .

G7. Processing example:
FIG. 22 is an explanatory diagram showing an example of processing in the dislocation mode 4. Here, in order to avoid complication of the figure, the content of the dislocation process is illustrated with only the center line of each road drawn, and finally, the dislocation result is shown. The thickness of the road line represents the importance of the road.
FIG. 22A shows a state before dislocation. In this example, an example is shown in which a road L1 having a low importance level and a road L2 having a high importance level are located from the inside with respect to the reference road. In this state, first, the road L1 on the inner side is the target of the shift process. Since the road L2 having high importance exists outside the road L1, this shift corresponds to the shift mode 4 (FIG. 17). Therefore, a dislocation process for fine dislocation is performed on the road L1. In the figure, the boundary lines of the occupied regions of fine dislocations, half dislocations, and all dislocations are indicated by broken lines. The dislocation is performed on a portion of the road L1 corresponding to the dislocation section in the area where the fine dislocation is occupied.
FIG. 22B shows a state of dislocation on the road L1. As indicated by the arrows, the road in the dislocation section is dislocated to the boundary of the occupied area of the fine dislocation.
When the dislocation of the road L1 is completed, the next is dislocation processing of the road L2 located outside.
Since the road L2 is in a state in which no road exists on the outer side and a road L1 having a low importance level exists on the inner side, this shift corresponds to the shift mode 1 (FIG. 17). Therefore, a dislocation process for all dislocations is performed on the road L2. In FIG. 22 (c), the occupied area of all dislocations is indicated by a broken line. The shift indicated by the arrow indicates that the occupied area of all dislocations has been expanded by the amount of the fine dislocation width in the dislocation process on the road L1.
FIG. 22D shows a state of dislocation on the road L2. For the entire road L2, the dislocation is performed up to the boundary of the occupied region of all dislocations.
FIG. 22 (e) shows the result of the dislocation process described above. The center lines of the reference road and the roads L1 and L2 are indicated by broken lines, and the line widths of the respective roads are indicated by hatching. As shown in the figure, as a result of the dislocation process, the road L1 is drawn with a minimum showing width even in the narrowest part, and the road L2 is drawn with a sufficient showing width.

FIG. 23 is an explanatory diagram showing an example of processing in the dislocation mode 3.
FIG. 23A shows a state before dislocation. This example shows an example in which a road L1 having a high importance level and a road L2 having a low importance level are located from the inside with respect to the reference road. In this state, first, the road L1 on the inner side is the target of the shift process. Since there is a road L2 of low importance outside the road L1, this shift corresponds to the shift mode 3 (FIG. 17). Accordingly, a three-stage shift process is performed on the road L1. In the figure, the boundary lines of the occupied regions of fine dislocations, half dislocations, and all dislocations are indicated by broken lines. The dislocation is performed according to the section in each occupied area in the road L1. That is, fine dislocation is performed in the fine dislocation section in the figure, half dislocation is performed in the half dislocation section, and total dislocation is performed in the entire dislocation section.
FIG. 23B shows a state of dislocation on the road L1. For each of the sections described above, the road L1 is transposed to the boundaries of the occupied areas of fine dislocation, half dislocation, and full dislocation. In this process, there is a section in which the road L1 is shifted beyond the road L2. It is the inversion section 1 and the inversion section 2 in the figure. For these sections, the positional relationship repair processing is necessary because the positional relationship between the roads L1 and L2 is reversed. Repair 1 and repair 2 indicated by arrows in FIG. 23C show a state in which the road L2 is transposed by the positional relationship repair process. By reversing the road L2 to the position of the road L1, the inversion of the positional relationship between the inside and the outside is eliminated.
When the dislocation of the road L1 is completed, the next is dislocation processing of the road L2 located outside.
Since the road L2 is in a state in which no road exists on the outer side and the road L1 having a high importance exists on the inner side, this rearrangement corresponds to the rearrangement mode 2 (FIG. 17). Accordingly, a step-wise shift process is performed on the road L2. In FIG. 23C, the boundary lines of the occupied areas are indicated by broken lines. The shift indicated by the arrow indicates that the occupied area of each stage is expanded by the amount of the fine dislocation width in the dislocation process of the road L1.
FIG. 23 (d) shows a state of dislocation on the road L2. On the road L2, the dislocation is performed up to the boundary of each occupied area for each of the fine dislocation section, the half dislocation section, and the entire dislocation section.
FIG. 23 (e) shows the result of the dislocation process described above. The center lines of the reference road and the roads L1 and L2 are indicated by broken lines, and the line widths of the respective roads are indicated by hatching. As shown in the drawing, as a result of the dislocation process, a sufficient width for the road L1 is secured, and a road width for the road L2 is secured and drawn.

G8. Variations:
In the second embodiment, an example is shown in which a processing region is divided in advance according to an interval between roads (see FIG. 14) and a dislocation process is performed for each processing region (see FIG. 15). As for the shift process between three or more roads, it is possible not to divide into processing areas in advance, but to proceed while selecting a processing target according to the interval between roads as needed during the shift process. Hereinafter, the contents of such processing will be shown as a modification.

24 and 25 are flowcharts of the map drawing data generation process of the modified example. First, the CPU selects a reference road based on the importance of the road (step S200), and sets a reference point sequence (step S202). The reference point sequence is a constituent point of the reference road. In the second embodiment, an example in which the reference road is selected for each processing region has been described. However, in the modification, the reference road is selected in the order of importance of the road. If it demonstrates in connection with the state shown in FIG. 14, in the first process, the expressway with the highest importance will be selected as a reference | standard road about this whole map, and a dislocation process will be performed. After that, the next most important national road is selected as the reference road, and the shift process is performed. In this way, the reference road is selected while decreasing the importance.
However, when processing is performed in this manner, there may be a case where the selected road is not necessarily suitable as the reference road over the entire section. For example, when the national road is selected as the reference road in the example of FIG. 14, in the areas A and B, the transfer process has already been performed on the national road with the expressway as the reference road. In this state, if the dislocation process is performed again using the national road as the reference road, useless and inappropriate dislocation process may be performed.
Therefore, at the time of setting the reference point sequence in step S202, only the constituent points of the reference road that have not been subjected to the dislocation process are extracted and used as the reference point sequence. This process has the same effect as dividing into processing areas in FIG.

  When the reference point sequence is set in this way, the CPU performs resampling processing (step S204), sets an overlap determination area (step S206), and detects an overlapping road (step S208). The setting of the overlap determination area is as described in the second embodiment (see step S21 in FIG. 16). In other words, the overlap determination area is set in consideration of the line width of the road on which the previous shift processing result has been applied. A road that overlaps the overlap determination area is detected as an overlap road. If there is no overlapping road (step S210), it means that it is not necessary to perform the shift process, and the CPU ends the process.

If there is an overlapping road (step S210), the dislocation process shown in FIG. 25 is performed.
First, the CPU selects a processing target road (step S212). The processing target road is an unprocessed road that is closest (inside) to the reference road among the overlapping roads. When the dislocation process for the road is the first time (step S214), the CPU performs the dislocation process (see FIG. 20) in the dislocation modes 3 and 4 (step S216). The processing contents of the dislocation modes 3 and 4 are the same as those in the second embodiment. When the dislocation process ends, the CPU retains a dislocation history for each overlap determination section (step S228). As the dislocation history to be held, the ID, importance, line width, etc. of the road to be processed are raised. The amount of dislocation and the occupied area width may be included.

On the other hand, in the case of the second and subsequent processing (step S214), the CPU sets the same history section (step S218). That is, the stored dislocation history is referred to, and among the plurality of overlapping sections, the sections holding the same history are grouped as one group.
Then, the positional relationship repair process is performed (step S220). The processing content is as described in the second embodiment (see FIG. 21).
After that, the shift mode is determined according to the importance of the road to be processed and the road inside (step S222), and the shift mode 1 (step S224) or the shift mode 2 (step S226) is determined according to the determination result. Perform dislocation processing. The contents of each dislocation process are as described in the second embodiment (see FIGS. 18 and 19). Even after completing these dislocation processes, the CPU retains a dislocation history for each overlap determination section (step S228).
By repeatedly executing the above processing, the same dislocation processing as described in the second embodiment can be realized.
Variations:

H. Effects and variations:
According to the dislocation process of Example 2 demonstrated above, a dislocation process is realizable among three or more roads. At this time, by performing the shift process from the inner road close to the reference road, it is possible to avoid the result of the shift process of the outer road from affecting the inner road. In addition, by switching the method of dislocation processing according to the importance of the inner and outer roads, it is possible to ensure an appropriate width for each road.

In the present invention, it is not always necessary to perform all the processing of the above-described embodiment, and only a part of the processing may be realized. Moreover, you may provide an additional process in the content mentioned above.
In the embodiment, the three-level occupied area is used, but the occupied area may be calculated according to the overlapping state of the two roads.
In the embodiment, the dislocation process between the roads has been described, but the dislocation between the railway and the road can be similarly processed.
Needless to say, the present invention is not limited to the above-described embodiments, and various configurations can be adopted without departing from the spirit of the present invention. For example, a part configured in hardware in the embodiment can be configured in software and vice versa.

  INDUSTRIAL APPLICATION When drawing a map, this invention can be utilized in order to improve the visibility of the part which routes overlap.

DESCRIPTION OF SYMBOLS 100 ... Map drawing data generation part 102 ... Resampling process part 104 ... Dislocation processing part 106 ... Post-processing part 110 ... Command input part 120 ... Map database 130 ... Map drawing database 140 ... Map drawing part

Claims (8)

A map drawing data generation method in which a computer generates map drawing data for drawing a map,
(A) reading route data representing a position and shape of a route overlapping at least partly from a map database to a memory;
(B) When one of the routes is set as a reference route , the width of the other route that should be drawn out of the reference route is set for each section according to the overlapping amount of the sections where the routes overlap each other. And a process of
(C) A shift process for shifting the position of the other route in the width direction with respect to the reference route so as to realize the set display width is performed, and map drawing data for drawing the route is generated. Process,
A method for generating map drawing data. The map drawing data generation method according to claim 1,
The step (c)
Setting an occupancy area having a width according to the viewing width from the center line of the reference route ;
The first condition that the dislocation process is not performed and the route in the occupied area is a section where the routes overlap with each other , and the center line of the reference route extends over the first predetermined length. Applying the dislocation treatment to a section that satisfies the second condition of being located on either one of both sides of the line ,
The map drawing data generation method , wherein the step of performing the dislocation process is re-executed at least twice based on a second occupied area larger than the previously set occupied area . The map drawing data generation method according to claim 2,
The step (c) is a step of performing the dislocation process for a section that satisfies a third condition that does not satisfy the second condition over a second predetermined length or more in a portion that satisfies the first condition. A map drawing data generation method. The map drawing data generation method according to claim 1, further comprising:
(D) Of the other route, a route that is hidden by the reference route at the end of the drawing range for drawing the map, and a route that is hidden by the reference route at a predetermined ratio or more of the total length of the other route A map drawing data generation method comprising a step of unconditionally performing a dislocation process on one or both of the above. A map drawing data generation method according to any one of claims 1 to 4,
Before Symbol reference line of the both sides of the center line at least one state near there are two or more lines other than the reference line on the side Rutoki,
Wherein step (b) and map drawing data generation method which processes of steps (c) from line to close before Symbol reference line in order. The map drawing data generation method according to claim 5, further comprising:
(E) When a dislocation process is performed on the route that exceeds another route located outside the route with respect to the reference route, the dislocation processing is performed on the other route that has been exceeded. A map drawing data generation method comprising a step of matching the route position or shifting the route position to the outside. A map drawing data generation method according to claim 5 or 6,
At least one of the show width in the step (b) and the shift amount in the step (c) is:
In order from the route adjacent to the reference route, a value obtained by adding the show width or the shift amount of the route to be subjected to the current shift process to the show width or the shift amount set in the already performed shift process is set. Map drawing data generation method. A map drawing data generation method according to any one of claims 5 to 7,
In the steps (b) and (c), the importance based on a predetermined criterion is set between a route to be subjected to the dislocation process and a route adjacent to the reference route outside the route. A map drawing data generation method that compares and changes the display width or shift amount of a section to be subjected to the dislocation processing based on the relationship of importance .

Images