CN109427238B

CN109427238B - Road character marking position determining method and device

Info

Publication number: CN109427238B
Application number: CN201710786679.5A
Authority: CN
Inventors: 柴艳瑞; 王海鹏; 苏向奎; 王前卫
Original assignee: Alibaba China Co Ltd
Current assignee: Alibaba China Co Ltd
Priority date: 2017-09-04
Filing date: 2017-09-04
Publication date: 2021-07-30
Anticipated expiration: 2037-09-04
Also published as: CN109427238A

Abstract

The application discloses a method and a device for determining a road character marking position, which are used for rapidly judging whether a road forming a navigation route exists in a geographic area covered by an electronic map to be displayed in a region intersection judging mode, and determining the marking position of the character to be marked according to a shape point set of the road under the condition of determining intersection, so that the problem of computing the road character marking position aiming at the road which is not displayed to cause computing resource waste is avoided, and computing resources are greatly saved.

Description

Road character marking position determining method and device

Technical Field

The application relates to the technical field of electronic map rendering, in particular to a method and a device for determining a road character marking position.

Background

Road character labeling is a key content of map display, and the quality of the road character labeling directly affects the experience of a user and is an important link for software quality assurance. The purpose of the road character labeling is to find a proper position on a map to perform character labeling on the road.

The existing road character labeling method generally includes that a server organizes road data required by a client, the road data comprises a shape point set and characters to be labeled, the shape point set and the characters to be labeled form a road to be labeled, the client calculates the length of the characters to be labeled, traverses the shape point set to find a position where the characters to be labeled are placed, and then labels the characters. However, in some cases, the road to be marked is not in the coverage area of the electronic map to be displayed by the client, so that the prior art does not need to mark in the electronic map after the time is consumed to calculate the marked position, which results in wasted calculation resources.

Disclosure of Invention

In view of this, the present application provides a method and an apparatus for determining a road character marking position, which are used to solve the problem of computing the road character marking position for an undisplayed route in the prior art, thereby causing a waste of computing resources.

In order to achieve the above object, the following solutions are proposed:

a method for determining the position of a road character label comprises the following steps:

judging whether the electronic map to be displayed is the same as the geographical area covered by the displayed electronic map, wherein a navigation route is displayed on the displayed electronic map, and if the electronic map to be displayed is different from the geographical area covered by the displayed electronic map, acquiring the geographical area covered by the electronic map to be displayed;

and judging whether the geographic area range covered by the electronic map to be displayed is intersected with the geographic area range covered by the navigation route, if so, determining the marking position of the characters to be marked of the road in the electronic map to be displayed according to the shape point set of the road forming the navigation route.

Preferably, the method further comprises:

obtaining the map zoom level of the electronic map to be displayed and the line width information of the road;

and according to the map zoom level and the line width information of the road, thinning the shape points in the shape point set of the road to obtain the shape point set of the road after thinning.

Preferably, the thinning the shape points in the shape point set of the road according to the map zoom level and the line width information of the road to obtain a shape point set of the road after thinning includes:

obtaining a rarefaction jumping point threshold value of the road according to the map zoom level and the line width information of the road;

sequentially selecting a shape point from the shape point set of the road, and calculating the distance between the selected shape point and the next adjacent shape point;

comparing the map zoom level with a set map zoom level threshold, if the map zoom level is greater than the set map zoom level threshold, judging whether the distance exceeds the rarefaction skip point threshold, if so, retaining the selected shape point, and if not, rarefaction the selected shape point;

the remaining shape points constitute the set of shape points for the road after thinning.

Preferably, each shape point in the shape point set is provided with a thinning mark, and the method further comprises:

if the map zoom level does not exceed the set map zoom level threshold, judging whether the value of the rarefaction mark of the selected shape point represents that the rarefaction mark is effective or not;

if the thinning mark is effective, thinning the selected shape point;

if the rarefaction mark is invalid, judging whether the distance exceeds the rarefaction jump point threshold value, if so, retaining the selected shape point, and if not, rarefaction is performed on the selected shape point;

Preferably, the obtaining the sparse skip point threshold of the road according to the map zoom level and the line width information of the road includes:

obtaining a rarefaction jumping point threshold value calculation formula corresponding to the map zooming level;

and calculating the sparse skip point threshold according to the obtained sparse skip point threshold calculation formula and the line width of the road.

Preferably, the determining, according to the shape point set of the road constituting the navigation route, a labeling position of the text to be labeled of the road in the electronic map to be displayed includes:

obtaining a section of continuous target shape points according to the positions of the shape points in the shape point set of the road forming the navigation route, wherein the target shape points form a target road section for marking characters to be marked of the road, the length of the target road section is not less than the length of the characters to be marked, and the tortuosity meets a set tortuosity condition;

and acquiring the road section which can mark the characters to be marked of the road in the target road section as the marking position of the characters to be marked of the road.

Preferably, the obtaining a continuous section of target shape points according to the positions of the shape points in the shape point set of the road forming the navigation route, where the target shape points form a target road segment for labeling the text to be labeled of the road, includes:

dividing the shape points of the road into a plurality of sections according to the position relation between the positions of the shape points in the shape point set of the road forming the navigation route and the geographic area covered by the electronic map to be displayed, wherein each section comprises the shape points positioned in the geographic area covered by the electronic map to be displayed;

for each divided segment, determining the maximum distance between adjacent shape points contained in the segment;

comparing the maximum spacing of adjacent shape points contained in each section, and determining the section with the maximum median of the maximum spacing as a candidate section;

taking a road section consisting of shape points with the distance equal to the maximum distance in the candidate sections as a central road section;

calculating the length of the character to be marked;

judging whether the length of the candidate segment is greater than that of the character to be marked;

if so, taking the shape points at the two ends of the central road section as starting points and taking the shape points at the two ends of the candidate section as end points;

for each starting point, sequentially searching shape points which accord with a set zigzag condition from the starting point to shape points of the candidate segment between the starting point and the adjacent end point of the candidate segment until searching a stop shape point corresponding to the starting point, wherein the stop shape point is not accord with the set zigzag condition or the stop shape point is the end point;

and taking a road section consisting of shape points between two stop shape points corresponding to the two starting points as a target road section.

Preferably, the sequentially searching shape points meeting the set zigzag condition from the starting point to the shape points of the candidate segment between the starting point and the adjacent end point thereof until searching the stop shape point corresponding to the starting point includes:

from the starting point P₀Starting, sequentially selecting shape points from the shape points of the candidate segment between the starting point and the adjacent end point, if the selected shape point is the end point, the selected shape point is a stop shape point, otherwise, executing the following steps:

when the shape point P is selected₁Then obtain < P₁P₀P’₀If the angle value is greater than a preset first angle threshold value, then P is₁Is the starting point P₀A corresponding stop shape point;

when the shape point P is read_iThe initial value of i is 2, and the angle P is acquired_iP_i-1P_i-2And < P_iP₀P’₀Each shape point i ═ i +1, P 'is selected'₀To be distinguished from P₀Another starting point of (a);

if < P_iP_i-1P_i-2Is greater than a preset first angle threshold value or less than P_iP₀P’₀Is greater than a preset second angle threshold, then P is_iIs the starting point P₀Corresponding stop shape points.

Preferably, in the target road segment, acquiring a road segment to be labeled with a text that can label the road includes:

generating at least one rectangular frame between adjacent shape points of the target road section according to the length of a single character to be marked in the characters to be marked of the road and obtaining the position of the rectangular frame, wherein the distance between the center points of the adjacent rectangular frames between the adjacent shape points is equal to the length of the single character to be marked;

determining whether the generated rectangular frame is occupied or not according to the position of the occupied rectangular frame and the position of the generated rectangular frame;

dividing continuous rectangular frames which are determined to be unoccupied and the number of which is not less than the number of characters to be marked into a rectangular frame group;

if only one rectangular frame group is arranged, the road section occupied by the rectangular frame group on the target road section is a road section capable of being marked with characters to be marked of the road;

if the number of the rectangular frame groups is more than two, the distance value from the road section occupied by the rectangular frame group on the target road section to the central road section is obtained, and the road section corresponding to the minimum distance value is the road section where the characters to be marked of the road can be marked.

A road letter marking position determining device, comprising:

the area judgment unit is used for judging whether the electronic map to be displayed is the same as the geographical area covered by the displayed electronic map, and a navigation route is displayed on the displayed electronic map;

the area acquisition unit is used for acquiring the geographical area range covered by the electronic map to be displayed when the judgment results of the area judgment units are different;

the intersection judging unit is used for judging whether the geographic area range covered by the electronic map to be displayed is intersected with the geographic area range covered by the navigation route;

and the marking position determining unit is used for determining the marking position of the character to be marked of the road in the electronic map to be displayed according to the shape point set of the road forming the navigation route when the judgment result of the intersection judging unit is intersection.

Preferably, the apparatus further comprises:

the information acquisition unit is used for acquiring the map zoom level of the electronic map to be displayed and the line width information of the road;

and the thinning unit is used for thinning the shape points in the shape point set of the road according to the map zoom level and the line width information of the road to obtain the shape point set of the road after thinning.

Preferably, the process of performing, by the rarefying unit, rarefying of the shape points in the shape point set of the road according to the map zoom level and the line width information of the road to obtain the shape point set of the road after rarefying specifically includes:

comparing the map zoom level with a set map zoom level threshold, if the map zoom level is greater than the set map zoom level threshold, judging whether the distance exceeds the rarefaction skip point threshold, if so, determining to keep the selected shape point, and if not, determining to rarefaction the selected shape point;

Preferably, each shape point in the shape point set is provided with a thinning mark, and the process of thinning the shape point set of the road by the thinning unit according to the map zoom level and the line width information of the road to obtain the thinned shape point set of the road further includes:

if the thinning mark is effective, thinning the selected shape point;

if the rarefaction mark is invalid, judging whether the distance exceeds the rarefaction jump point threshold value, if so, determining to reserve the selected shape point, and if not, determining to rarefaction the selected shape point;

Preferably, the process of obtaining the rarefaction trip point threshold of the road by the rarefaction unit according to the map zoom level and the line width information of the road specifically includes:

Preferably, the process of determining the labeling position of the text to be labeled of the road in the electronic map to be displayed according to the shape point set of the road forming the navigation route by the labeling position determining unit specifically includes:

and searching a road section which can mark characters to be marked of the road in the target road section to serve as a marking position of the characters to be marked of the road.

Preferably, the labeling position determining unit obtains a continuous section of target shape points according to positions of shape points in a shape point set of a road forming the navigation route, where the target shape points form a process for labeling a target road segment of a character to be labeled of the road, and the process specifically includes:

calculating the length of the character to be marked;

Preferably, the process of sequentially searching shape points meeting the set meandering condition from the starting point to the shape points of the candidate segment located between the starting point and the adjacent end point until searching the stop shape point corresponding to the starting point by the labeling position determining unit specifically includes:

Preferably, the process of acquiring, by the labeling position determining unit, the road segment to be labeled with the text of the road in the target road segment specifically includes:

According to the technical scheme, the road character marking position determining scheme provided by the embodiment of the application judges whether the electronic map to be displayed is the same as the geographic area covered by the displayed electronic map, the displayed electronic map shows a navigation route, and if the electronic map to be displayed is different from the displayed electronic map, the geographic area covered by the electronic map to be displayed is obtained; and judging whether the geographic area range covered by the electronic map to be displayed is intersected with the geographic area range covered by the navigation route, if so, indicating that roads forming the navigation route exist in the geographic area range covered by the electronic map to be displayed, and determining the marking positions of the characters to be marked of the roads in the electronic map to be displayed according to the shape point set of the roads forming the navigation route. According to the method and the device, whether the road forming the navigation route exists in the geographic area covered by the electronic map to be displayed is quickly judged in the area intersection judgment mode, the marking position of the character to be marked is determined according to the shape point set of the road under the condition that the intersection is determined, the problem that the calculation of the marking position of the character of the road aiming at the road which is not displayed is caused, and therefore calculation resources are wasted is solved, and the calculation resources are greatly saved.

Drawings

In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings needed to be used in the description of the embodiments or the prior art will be briefly introduced below, it is obvious that the drawings in the following description are only embodiments of the present application, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.

Fig. 1 is a flowchart of a method for determining a road marking position according to an embodiment of the present application;

2a-2b illustrate two intersecting schematic views of a geographic area covered by an electronic map to be displayed and a navigation route covering the geographic area;

FIG. 3 is a flowchart of another method for determining a road marking position according to the embodiment of the present application;

FIG. 4 is a flowchart of a method for thinning a set of shape points as disclosed in an embodiment of the present application;

FIG. 5 is a flowchart of a method for determining a labeling position of a character to be labeled according to a shape point set, disclosed in an embodiment of the present application;

fig. 6 is a flowchart of a method for determining a target road segment according to an embodiment of the present disclosure;

FIG. 7 is a schematic diagram illustrating a road shape point division manner according to an example of the present application;

FIG. 8 is a flowchart of a method for finding shape points meeting a predetermined inflection condition according to an embodiment of the present disclosure;

FIG. 9 is a schematic diagram of searching shape points meeting a set meandering condition in the candidate segment according to the embodiment of the present application;

FIG. 10 is a flowchart illustrating a method for searching a segment of a target road for a segment of a callable text according to an embodiment of the present disclosure;

FIG. 11 is a schematic diagram illustrating an effect of finding a segment of a callable text in a target segment according to an example of the present application;

FIG. 12a is a schematic diagram of a display effect after road character labeling according to the prior art;

FIG. 12b is a schematic diagram illustrating a display effect of the road text labeled according to the method of the present application;

fig. 13 is a schematic structural diagram of a device for determining a road marking position according to an embodiment of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Referring to fig. 1, fig. 1 is a flowchart of a method for determining a road character labeling position disclosed in the embodiment of the present application.

As shown in fig. 1, the method includes:

step S100, judging whether the electronic map to be displayed is the same as the geographical area covered by the displayed electronic map, wherein a navigation route is displayed on the displayed electronic map, and if not, executing step S110;

specifically, the navigation route displayed on the electronic map displayed by the client is drawn according to the shape point set of the roads constituting the navigation route acquired from the server.

When the client responds to the dragging operation of a user, the zoom level operation of the zoom map or other operations which may involve changing the range of the geographic area covered by the displayed electronic map and needs to render the map (including the map and the navigation route) again, whether the electronic map to be displayed is the same as the geographic area covered by the displayed electronic map or not is judged. It can be understood that if the covered geographic areas are the same, the drawing of the road marking is not required to be performed again, otherwise, the drawing of the road marking is required to be performed again.

Step S110, acquiring a geographical area range covered by an electronic map to be displayed;

specifically, the geographic area covered by the electronic map to be displayed can be determined by calling the map engine interface, and the geographic area is a rectangular area generally.

Step S120, judging whether the geographical area range covered by the electronic map to be displayed is intersected with the geographical area range covered by the navigation route, if so, executing step S130; if not, the situation that the road forming the navigation route does not exist in the electronic map to be displayed is shown, and the road marking does not need to be drawn again.

Wherein the geographic area range covered by the navigation route may be a range of geographic areas surrounding all shape points in a set of shape points constituting a road of the navigation route.

In this step, the intersection judgment is performed on the geographical area range covered by the electronic map to be displayed and the geographical area range covered by the navigation route. It is understood that if the two are intersected, it indicates that the electronic map to be displayed has the road forming the navigation route, otherwise, it indicates that the electronic map to be displayed does not have the road forming the navigation route.

Referring to fig. 2a and 2b, two intersecting schematic diagrams of a geographical area covered by an electronic map to be displayed and a geographical area covered by a navigation route are illustrated.

The geographical area covered by the electronic map to be displayed can be represented by bounds1, and the geographical area covered by the navigation route can be represented by bounds 2.

Step S130, determining the marking position of the character to be marked of the road in the electronic map to be displayed according to the shape point set of the road forming the navigation route.

Specifically, when the intersection is judged in the previous step, it is described that the electronic map to be displayed has a road forming a navigation route, so that the marking position of the text to be marked of the road in the electronic map to be displayed is determined according to the shape point set of the road forming the navigation route. Of course, if the intersection is determined in the previous step, it indicates that there is no road forming the navigation route in the electronic map to be displayed, and therefore, the calculation of the marked position may not be performed, so as to save the calculation resources.

According to the method for determining the road character marking position, whether the road forming the navigation route exists in the geographic area covered by the electronic map to be displayed is rapidly judged in a region intersection judgment mode, the marking position of the character to be marked is determined according to the shape point set of the road under the condition that intersection is determined, the problem that calculation resources are wasted due to the fact that the road character marking position is calculated for the road which is not displayed is avoided, and calculation resources are greatly saved.

Referring to fig. 3, fig. 3 is a flowchart of another road text labeling position determining method disclosed in the embodiment of the present application. As shown in fig. 3, the method includes:

step S200, judging whether the electronic map to be displayed is the same as the geographical area covered by the displayed electronic map, wherein a navigation route is displayed on the displayed electronic map, and if not, executing step S210;

step S210, acquiring a geographical area range covered by an electronic map to be displayed;

step S220, judging whether the geographical area range covered by the electronic map to be displayed is intersected with the geographical area range covered by the navigation route, if so, executing step S230;

specifically, the processes of steps S200 to S220 correspond to steps S100 to S120 in the above embodiments one to one, and the detailed description can refer to the foregoing, which is not repeated herein.

Step S230, obtaining the map zoom level of the electronic map to be displayed and the line width information of the road;

specifically, the client may store a style file in which line width information of a road may be specified. Of course, the client may also obtain the line width information of the road from the server.

Step S240, according to the map zoom level and the line width information of the road, thinning the shape points in the shape point set of the road to obtain the shape point set of the road after thinning;

and S250, determining the marking position of the characters to be marked of the road in the electronic map to be displayed according to the shape point set of the road after rarefaction of the navigation route.

Compared with the previous embodiment, the method and the device have the advantages that according to the map zoom level and the line width information of the road, the shape point set of the road is thinned, the efficiency of calculating the marked position is improved to a certain extent, meanwhile, due to the fact that the thinning reduces some shape points, the distance between the shape points is increased, and therefore the probability of obtaining the marked position is improved.

Further, for the above S240, according to the map zoom level and the line width information of the road, the shape points in the shape point set of the road are thinned, so as to obtain a shape point set of the thinned road, which will be described in detail with reference to specific embodiments in the following.

Before describing the rarefaction embodiment, a further description of the set of shape points of the road is first made. The client can obtain the shape point set of the road from the server, each shape point in the shape point set can be further provided with a rarefaction mark, and different values of the rarefaction mark indicate whether the rarefaction mark is effective or not. If the rarefaction flag is valid, it indicates that the corresponding shape point may be directly rarefed when the map zoom level is less than the set map zoom level threshold. The server sets the rarefaction marks of a part of unimportant shape points in the shape point set to be effective when the map zoom level is smaller than the set map zoom level threshold value according to the actual situation of the road in advance, so that the client can determine whether to rarefaction the corresponding shape points according to the marks. Wherein setting the map zoom level threshold may be practical, such as 10 or other values. For example, when the rarefaction flag is 0, it indicates that the rarefaction flag is valid, and the corresponding shape point may be directly rarefied when the map zoom level is less than 10 levels.

Based on the above description, an embodiment of the present application discloses a flowchart of a method for rarefying a set of shape points of a road, as shown in fig. 4, the method includes:

step S300, obtaining a rarefaction jumping point threshold value of the road according to the map zoom level and the line width information of the road;

specifically, the sparse skip point threshold filterLen calculation formula corresponding to the map zoom level may be designed in advance, or the sparse skip point threshold calculation formula corresponding to the combination of the map zoom level and the number of shape points in the shape point set may be designed. The calculation formula of the rarefaction jump point threshold filterLen is a numerical relationship between the rarefaction jump point threshold filterLen and the line width of the road.

Based on the above, a rarefaction formula corresponding to the map level or the combination of the map level and the number of shape points in the shape point set of the road may be obtained, and the rarefaction skip point threshold filterLen of the road may be calculated according to the rarefaction formula and the line width information of the road. Namely, the line width of the road is brought into the obtained calculation formula of the rarefaction trip point threshold filterLen, and then the rarefaction trip point threshold filterLen is obtained.

Examples are as follows:

in the embodiment of the present application, the map zoom level is divided into four cases, where the four cases correspond to different sparse skip point threshold filterLen calculation formulas respectively, as follows:

(1) nMaplevel > 17, filterLen > 0 means no thinning;

(2) nMapLevel is 15 and 16 grades, and filterLen is k1 nLineWidth;

(3) the nMapLevel is 9, the number of the shape points in the shape point set is 100, and the filterLen is k2 nLineWidth;

(4) and the rest of filterLen k3 nLineWidth.

The nMapplevel represents the map zoom level, fileLen represents the thinning skip point threshold, nLineWidth represents the line width of the road, and k1-k3 represent coefficient values.

S310, sequentially selecting a shape point from the shape point set of the road, and calculating the distance nTempLen between the selected shape point and the next adjacent shape point;

specifically, a shape point P is selected from the shape point set of the road in sequence_iCalculating the shape point P_iAnd the next adjacent shape point P_i+1The distance between nTempLen.

Step S320, judging whether the map zooming level is larger than a set map zooming level threshold value; if yes, go to step S330, otherwise go to step S340;

step S330, determining whether the shape points are thinned or not according to the size relationship between the nTempLen and the filterLen;

specifically, if the map zoom level is greater than the set map zoom level threshold, only the size relationship between the nTempLen and the filterLen needs to be considered when determining whether to rarefize the shape point i.

In an optional embodiment, it may be determined whether nTempLen exceeds filterLen, and if yes, it is determined that the selected shape point P is retained_iIf not, determining the shape point P to be selected_iAnd (4) draining.

Wherein the reserved shape points form a shape point set of the road after rarefaction.

And step S340, determining whether the shape point is thinned according to the value of the thinning mark of the shape point and the size relation between the nTempLen and the filterLen.

Specifically, if the map zoom level does not exceed the set map zoom level threshold, the shape point P to be selected is determined_iWhen the water is drained, the shape point P needs to be considered comprehensively_iAnd the size relationship between the nTempLen and the filterLen.

In an optional embodiment, if the map zoom level does not exceed the set map zoom level threshold, the selected shape point P is determined_iWhether the value of the rarefaction mark indicates that the rarefaction mark is effective or not; if the rarefaction mark is indicated to be effective, the selected rarefaction mark is selectedShape point P_iDraining off; if the rarefaction mark is invalid, judging whether nTempLen exceeds filterLen, if so, determining to keep the selected shape point P_iIf not, determining the shape point P to be selected_iAnd (4) draining.

Further, as to the step S130, determining the labeling position of the to-be-labeled character of the road in the electronic map to be displayed according to the shape point set of the road constituting the navigation route, the following application will be described with reference to fig. 5, and this embodiment may include:

step S400, obtaining a section of continuous target shape points according to the positions of shape points in a shape point set of a road forming the navigation route, wherein the target shape points form a target road section for marking characters to be marked of the road, the length of the target road section is not less than the length of the characters to be marked, and the tortuosity meets set tortuosity conditions;

the length of the character to be marked can be calculated according to the character attribute, and generally, the length of the character to be marked is equal to the width of the area occupied by a single character to be marked multiplied by the number of the characters to be marked.

The tortuosity of the target road section also needs to meet the set tortuosity condition, that is, the target road section needs to be guaranteed to be as flat as possible, and the situation that the tortuosity is too large is avoided, so that the marked characters are not convenient for users to watch.

It should be noted that the degree of tortuosity of the target road segment may be determined by an included angle between sub-road segments formed by adjacent shape points in each shape point included in the target road segment.

Further, if the shape points in the shape point set of the road are thinned out before step S400, the shape point set of the road in this step is the shape point set of the road after thinning out.

And step S410, acquiring a road section which can be marked with the characters to be marked of the road from the target road section, and using the road section as a marking position of the characters to be marked of the road.

After the target road section is found, a road section which can mark characters to be marked of the road is further found from the target road section, specifically, the road section which is not occupied by other characters and has a length not less than the length of the characters to be marked of the road can be found.

It will be appreciated that the number of road segments eventually found is not fixed, and may be zero or one or more.

If the number of the searched road sections is zero, the road sections which meet the conditions are not searched, the characters to be marked cannot be marked, and quitting is performed, namely the characters to be marked are not marked.

If the number of the searched road sections is one or more, determining one road section from the searched road sections as the marking position of the characters to be marked on the road.

In the method for determining the marking position of the to-be-marked character on the road introduced in this embodiment, first, a target road segment meeting a condition is searched for in a shape point set, and further, a road segment, where the to-be-marked character on the road can be marked, is obtained from the target road segment, and the marking position of the to-be-marked character on the road is determined from the road segment. According to the method, the finally found marking position is ensured to be in a relatively flat road section, and the user can conveniently check the marked characters.

In another embodiment of the present application, regarding step S400, a process of obtaining a continuous segment of target shape points according to positions of shape points in a shape point set of roads constituting the navigation route, where the target shape points constitute a target link for labeling characters to be labeled on the roads is described with reference to fig. 6, where the method includes:

step S500, dividing the shape points of the road into a plurality of sections according to the position relation between the position of the shape points in the shape point set of the road forming the navigation route and the geographic area covered by the electronic map to be displayed;

and according to a certain division rule, ensuring that each divided section can contain shape points in the geographic area covered by the electronic map to be displayed.

In an alternative embodiment, shape points in the shape point set of the road may be traversed to determine a critical shape point, where the critical shape point is located outside the geographic area covered by the electronic map to be displayed, and a previous adjacent shape point or a next adjacent shape point of the critical shape point is located inside the geographic area covered by the electronic map to be displayed. And dividing the critical shape points and the shape points between the critical shape points, which are positioned in the geographic area covered by the electronic map to be displayed, into a segment.

The shape point division process of the road is explained with reference to fig. 7:

the route illustrated in fig. 7 includes P0-Pn shape points, and the electronic map to be displayed covers a geographical area S1. As can be seen from fig. 7, P1, P5, P9, P11, and P14 are critical shape points, and thus the shape points are divided into three segments, which are:

[P1…P5]、[P5…P9]、[P11…P14]。

step S510, aiming at each divided segment, determining the maximum distance between adjacent shape points contained in the segment;

specifically, each segment after division includes a number of shape points. The pitch between adjacent shape points is determined, and the maximum pitch is determined from the pitches.

Step S520, comparing the maximum distance between adjacent shape points contained in each section, and determining the section with the maximum median value of the maximum distance as a candidate section;

specifically, a maximum pitch is determined for each segment in the previous step. In this step, the sizes of the maximum distances are compared, and the segment with the maximum median value of the maximum distances is determined as a candidate segment.

Specifically, the following description will be made by taking the above fig. 7 as an example:

as can be seen from FIG. 7, the maximum pitch in the [ P1 … P5] segments is [ P1-P2] segment length L1; the maximum distance among the sections [ P5 … P9] is [ P6-P7] the length of the section L2; the maximum distance among the sections [ P11 … P14] is L3, and the sections [ P12-P13] are long. Assuming that L3> L1> L2, the candidate segment can be determined to be [ P12-P13 ].

In this step, the segment with the largest median of the maximum distances is determined as a candidate segment from the divided segments, and then the target road segment can be intercepted from the candidate segment. Because the candidate segment comprises the adjacent shape points with the largest distance, the probability of obtaining the position which is enough to contain the character to be marked by calculation from the candidate segment is larger, the probability of obtaining the marking position by calculation is improved, and the calculated marking position is ensured to be close to the flat road segment.

Step S530, taking a road section formed by shape points with the distance equal to the maximum distance in the candidate sections as a central road section;

step S540, calculating the length of the character to be marked;

step S550, judging whether the length of the candidate segment is larger than the length of the character to be marked; if not, exiting; if yes, go to step S560;

specifically, if the length of the candidate segment is not greater than the length of the character to be marked, it indicates that the marking position cannot be found, and the process can be exited to end.

Step S560, taking the shape points at the two ends of the central road section as starting points and the shape points at the two ends of the candidate section as end points;

step S570, for each starting point, starting from the starting point, sequentially searching shape points meeting the set meandering condition among the shape points of the candidate segment between the starting point and its adjacent end points until a stop shape point corresponding to the starting point is searched;

wherein the stop shape point is not in accordance with a set meandering condition or the stop shape point is the end point.

Step S580 is to take a link composed of shape points between two stop shape points corresponding to two start points as a target link.

In the method for finding a target road segment disclosed in this embodiment, the shape points of the road are divided into a plurality of segments according to the coverage area of the electronic map to be displayed, each segment includes the shape points located in the coverage area of the electronic map to be displayed, a candidate segment including the adjacent shape points with the largest distance is determined from the divided segments, and the target road segment is subsequently intercepted from the candidate segment. Because the candidate segment comprises the adjacent shape points with the largest distance, the probability of obtaining the position which is enough to contain the character to be marked by calculation from the candidate segment is larger, the probability of obtaining the marking position by calculation is improved, and the calculated marking position is ensured to be close to the flat road segment.

In another embodiment of the present application, regarding step S570, for each starting point, a process of sequentially finding shape points meeting a set meandering condition from the starting point to shape points of the candidate segment located between the starting point and its adjacent end point until finding a stop shape point corresponding to the starting point is described, and with reference to fig. 8, the method includes:

step S600, starting from the starting point P₀Starting, and sequentially selecting shape points from the shape points of the candidate segment between the starting point and the adjacent end point;

specifically, the shape points at both ends of the center link are respectively starting points, one of which is denoted as P₀And the other origin is represented by P'₀。

Step S610, determining whether the selected shape point is the end point, if so, performing step S620, otherwise, performing step S630;

step S620, determining the selected shape point as a starting point P₀A corresponding stop shape point;

step S630, when the shape point P is selected₁Then obtain < P₁P₀P’₀The angle value of (d);

step S640, if the angle value is larger than a preset first angle threshold value, the P value is₁Is the starting point P₀A corresponding stop shape point;

step S650, when it is read that the shape point P is_iThe initial value of i is 2, and the angle P is acquired_iP_i-1P_i-2And < P_iP₀P’₀Every shape point i is selected as i + 1;

step S660, if & lt P_iP_i-1P_i-2Is greater than a preset first angle threshold value or less than P_iP₀P’₀Is greater than a preset second angle threshold, then P is_iIs the starting point P₀Corresponding stop shape points.

The first angle threshold and the second angle threshold can be set by themselves, and the size relationship between the first angle threshold and the second angle threshold is not limited.

For ease of understanding, we now illustrate:

referring to fig. 9, fig. 9 is a schematic diagram of finding shape points meeting a set meandering condition in the candidate segment according to the embodiment of the present application.

In FIG. 9, P1-Pn is the shape point included in the candidate link, and [ Pn4-Pn5] is the center link.

For the process of expanding a query from Pn4 to the P1 side, the following is:

1. an angle ^ Pn3Pn4Pn5 between a vector from Pn3 to Pn4 and a vector from Pn4 to Pn5 is calculated, and the angle is determined to be smaller than a 1. And continuing to detect forwards.

2. Calculating an included angle between a vector from Pn2 to Pn3 and a vector from Pn3 to Pn4, namely ^ Pn2Pn3Pn4, and determining that the included angle ^ Pn2Pn3Pn4 is smaller than a 1;

3. an angle ≈ Pn2Pn4Pn5 between a vector from Pn2 to Pn4 and a vector from Pn4 to Pn5 is calculated, and the angle ≈ Pn2Pn4Pn5 is determined to be smaller than a 2. And continuing to detect forwards.

4. An angle ^ Pn1Pn2Pn3 between a vector from Pn1 to Pn2 and a vector from Pn2 to Pn3 is calculated, and the angle ^ Pn1Pn2Pn3 is determined to be larger than a1, so that Pn1 is determined to be a stop shape point.

For the process of expanding a query from Pn5 to Pn side, the following is:

1. an angle ^ Pn6Pn5Pn4 between a vector from Pn6 to Pn5 and a vector from Pn5 to Pn4 is calculated, and the angle ^ Pn6Pn5Pn4 is determined to be smaller than a 1. And continuing to detect forwards.

2. Calculating an included angle between a vector from Pn7 to Pn6 and a vector from Pn6 to Pn5, namely ^ Pn7Pn6Pn5, and determining that the included angle ^ Pn7Pn6Pn5 is smaller than a 1;

3. an angle ≈ Pn7Pn5Pn4 between a vector from Pn7 to Pn5 and a vector from Pn5 to Pn4 is calculated, and the angle ≈ Pn7Pn5Pn4 is determined to be larger than a2, so that Pn7 is determined to be a stop shape point.

Finally, a link composed of shape points between Pn1 to Pn7 is determined as a target link, where the target link does not include Pn1 and Pn 7.

In another embodiment of the present application, regarding step S410, a process of obtaining, from the target road segment, a road segment to be labeled with a text that can be labeled on the road is used as a labeling position of the text to be labeled on the road is described, and with reference to fig. 10, the method includes:

step S700, generating at least one rectangular frame between adjacent shape points of the target road section according to the length of a single character to be marked in the characters to be marked of the road and obtaining the position of the rectangular frame;

and the distance between the center points of the adjacent rectangular frames between the adjacent shape points is equal to the length of the single character to be marked.

Step S710, determining whether the generated rectangular frame is occupied or not according to the position of the occupied rectangular frame and the position of the generated rectangular frame;

specifically, the present application may store the positions of occupied rectangular frames in advance. Furthermore, in this step, it may be determined whether the generated rectangular frame is occupied or not according to the position of the occupied rectangular frame and the position of the generated rectangular frame.

Step S720, dividing continuous rectangular frames which are determined to be unoccupied and the number of which is not less than the number of characters to be marked into a rectangular frame group;

step 730, if only one rectangular frame group is provided, the road section occupied by the rectangular frame group on the target road section is a road section capable of being marked with the characters to be marked of the road;

step S740, if there are more than two rectangular frame groups, obtaining a distance value from the road segment occupied by the rectangular frame group on the target road segment to the central road segment, where the road segment corresponding to the minimum distance value is a road segment where the character to be labeled of the road can be labeled.

Optionally, an optional implementation manner of obtaining a distance value from a road segment occupied by the rectangular frame group on the target road segment to the center road segment is introduced in the embodiment of the present application. For convenience of expression, the road sections occupied by the rectangular box groups on the target road sections are defined as occupied sections. The distance value obtaining manner may include:

and calculating the distance between the center point of the occupation section and the center point of the center road section as the distance value of the two.

In addition, the distance between the start point of the occupation section and the start point of the center section or the distance between the end point of the occupation section and the end point of the center section can be calculated as the distance value between the two.

In this embodiment, the road segment corresponding to the minimum distance value may be selected as the road segment where the character to be marked of the road can be marked. Because the central road section is a straight line, the road section closest to the central road section is selected as the marking position, so that the marking characters are close to the flat road section, and the user can watch the marking characters more conveniently.

The procedure of the embodiment corresponding to fig. 10 is described with reference to the scenario illustrated in fig. 11.

The shape points P1-P6 in FIG. 11 constitute the target road segment, with P3-P4 constituting the center road segment. The number of the characters to be marked is 4.

And generating a rectangular frame between two adjacent shape points on the target road section, wherein the distance between the center points of the adjacent rectangular frames is equal to the length of a single character to be marked.

In fig. 11, white unfilled rectangular boxes represent unoccupied rectangular boxes, and diagonally filled rectangular boxes represent occupied rectangular boxes.

And dividing continuous and unoccupied rectangular frames with the number not less than the number of the characters to be marked into a rectangular frame group. From this, two rectangular frame groups, that is, the rectangular frame group seg1 and the rectangular frame group seg2 in fig. 11 can be obtained.

Because two rectangular frame groups exist, the distance values between the road sections occupied by the two rectangular frame groups on the target road section and the central road section are respectively calculated, and the road section corresponding to the minimum distance value, namely the road section corresponding to seg1, is selected as the road section of the markable road where the characters are to be marked.

According to the method for searching the marking position in the target road section, the available road section is searched in a rectangular frame mode and serves as the marking position of the character to be marked, and the searching result is more accurate.

The process of generating the rectangular frame in step S700 may be implemented as follows:

firstly, parameters are defined:

half of the width of a single character to be marked fHalfFontSize;

the target road section comprises a shape point set [ P1P2 … PN ];

recording the accumulated distance between the central point of the rectangular frame to be detected and the previous nearest shape point by using a variable fTmpOffSet as a mark for judging whether the line segment formed by two adjacent shape points is detected completely, wherein the initial length of the fTmpOffSet is fHalfFontSize;

counting the number of the rectangular frames, wherein the variable nRectCount is initially 0; the total number nSumCount of rectangle boxes that can be placed is recorded as target road section length/single character occupying length.

The implementation process is as follows:

the method comprises the following steps: sequentially taking a shape point from the shape point set [ P1P2 … PN-1], calculating the length of a line segment formed by the shape point and the next shape point to be fListRoadLen, and calculating a unit vector of the direction of the line segment for subsequent calculation;

step two: judging whether fTmpOffSet is less than or equal to fListRoadLen, if so, executing a third step, otherwise, executing a fourth step;

step three: based on the line segment starting point obtained in the first step, taking the position with the line segment end point direction length of fTmpOffSet as the center of a rectangular frame, generating a rectangular frame, wherein the width and the height of the generated rectangular frame are the width and the height of characters, and executing a fifth step;

step four: taking fTmpOffset-fListRoadLen, jumping out of the loop, and executing the step one;

step five: saving the position of the generated rectangular frame;

step six: and enabling nRectCount +1, judging whether nRectCount exceeds the maximum number nSumCount which can be placed, if yes, indicating that the target road sections are detected once, ending the whole detection, and ending the program. Otherwise, executing step seven;

step seven: judging whether fTmpOffset + fHalfFontSize 2 is larger than fListRoadLen, obviously, if so, indicating that the central point of the next rectangular frame is not on the current line segment, continuously detecting the next line segment, then, considering the residual part of the current line segment, resetting fTmpOffset, and if fTmpOffset + fHalfFontSize 2+ fTmpOffset-fListRoadLen, further executing the first step to continuously detect, and if fTmpOffset + fHalfFontSize 2 is not larger than fListRoadLen, indicating that the central point of the next rectangular frame is still on the current line segment, and continuously executing the eighth step;

step eight: resetting the fTmpOffset, wherein fTmpOffset is fTmpOffset + fHalfFontSize 2, namely adding a character length, and executing the step two.

Further, the process of determining the rectangular frame group in step S720 may be implemented as follows:

firstly, parameters are defined:

a flag array bFlagArray used for storing the state whether each generated rectangular frame is occupied, wherein the size of the flag array bFlagArray is equal to the number nVexNum of the generated rectangular frames; the number nCalCharSize of the characters to be marked; the number nCount of consecutive unoccupied rectangular boxes has been detected, initially 0.

The implementation process is as follows:

the method comprises the following steps: sequentially taking out the occupation states of the rectangular frames from the bFlagArray, judging whether the taken-out occupation states represent that the corresponding rectangular frames are unoccupied, if so, executing the step two, otherwise, executing the step three;

step two: and (4) enabling nCount +1, wherein the currently taken rectangular frame is an available rectangular frame, judging whether the currently taken rectangular frame is the starting point of the available continuous rectangular frame, if so, recording the position of the starting point, otherwise, not needing. Continuing to execute the first step;

step three: judging whether the number of the continuous unoccupied rectangular frames recorded in the front is enough, namely judging whether nCount > -nCalCharSize is met, if not, marking that a proper position is not found, restarting detection, executing the first step, and if so, executing the fourth step;

step four: recording the position of the nearest unoccupied rectangular frame before the current frame as an end position, and forming a continuous rectangular frame group which is determined to be unoccupied and the number of which is not less than the number of characters to be marked from the rectangular frame corresponding to the start position to the rectangular frame corresponding to the end position.

And finally, obtaining a plurality of rectangular frame groups after circularly traversing the occupation state of each rectangular frame in the bFlagArray.

Finally, in order to prove the effectiveness of the method for determining the position of the road character label provided in the embodiment of the present application, the following description is provided with reference to fig. 12a and 12 b:

at present, a planning route from Beijing to Tianjin needs to be marked with road characters. The effect marked according to the prior art is shown in fig. 12a, and the effect marked according to the method of the present application is shown in fig. 12 b.

Further, the method and the device divide the shape points of the road in a segmented mode, and determine the candidate segment containing the adjacent shape points with the largest distance, so that the probability of obtaining the position which is enough to contain the character to be marked by calculation from the candidate segment is larger, the probability of obtaining the marking position by calculation is improved, and the calculated marking position is close to a flat road section.

Furthermore, the method and the device use a rectangular frame mode to search the position which is not occupied by other characters, and prevent the character capping problem caused by the fact that other characters are marked on the searched marking position.

Comparing fig. 12a and 12b, it can be seen that the text labeling position cannot be calculated according to the prior art, so that the road text labeling cannot be displayed, and according to the scheme of the present application, the labeling position can be found, and the labeling position is located on a flat road section and is not covered with other text.

It should be understood that the embodiments described herein with the shape point set of the road as the processing object are all applicable to the shape point set of the road after thinning, and for details, refer to the relevant contents, and the detailed description is omitted here.

The following describes the road character marking position determining device provided in the embodiment of the present application, and the road character marking position determining device described below and the road character marking position determining method described above may be referred to in a corresponding manner.

Referring to fig. 13, fig. 13 is a schematic structural view of a road character marking position determining device disclosed in the embodiment of the present application.

As shown in fig. 13, the apparatus includes:

the area judgment unit 11 is configured to judge whether the electronic map to be displayed is the same as a geographic area covered by a displayed electronic map, where a navigation route is displayed on the displayed electronic map;

the area obtaining unit 12 is configured to obtain a geographical area range covered by the electronic map to be displayed when the determination result of the area determining unit is different;

an intersection judgment unit 13, configured to judge whether a geographic area range covered by the electronic map to be displayed and a geographic area range covered by the navigation route intersect;

and a marking position determining unit 14, configured to determine, when the intersection determination unit determines that the intersection is obtained as a result of the intersection determination, a marking position of the to-be-marked text of the road in the electronic map to be displayed according to the shape point set of the road forming the navigation route.

The road character marking position determining device provided by the embodiment of the application can be used for rapidly judging whether roads forming a navigation route exist in the geographic area covered by the electronic map to be displayed in a region intersection judging mode, and determining the marking position of the character to be marked according to the shape point set of the roads under the condition of determining intersection, so that the problem of computing the road character marking position aiming at the road which is not displayed, thereby causing the waste of computing resources is avoided, and the computing resources are greatly saved.

Optionally, the apparatus of the present application may further include:

Optionally, the process of performing, by the rarefying unit, rarefying of the shape points in the shape point set of the road according to the map zoom level and the line width information of the road to obtain the shape point set of the road after rarefying may specifically include:

Optionally, each shape point in the shape point set is provided with a rarefaction mark, and the process of rarefaction unit rarefaction the shape point set of the road according to the map zoom level and the line width information of the road to obtain the shape point set of the road after rarefaction may further include:

if the thinning mark is effective, thinning the selected shape point;

Optionally, the process of calculating the rarefaction trip point threshold by the rarefaction unit according to the map zoom level and the line width information of the road may specifically include:

the sparse skip point threshold value calculation formula specifies the numerical relationship between the sparse skip point threshold value and the line width of the road under the corresponding map zoom level.

Optionally, the process of determining, by the labeled position determining unit, a labeled position of the to-be-labeled character of the road in the to-be-displayed electronic map according to the shape point set of the road constituting the navigation route may specifically include:

Optionally, the labeling position determining unit obtains a continuous section of target shape points according to positions of shape points in a shape point set of a road forming the navigation route, where the target shape points form a process for labeling a target road segment of a text to be labeled on the road, and the process may specifically include:

calculating the length of the character to be marked;

Optionally, the process of sequentially searching, from the starting point to shape points of the candidate segment located between the starting point and its adjacent end point, shape points that meet the set meandering condition until a stop shape point corresponding to the starting point is searched by the labeled position determining unit may specifically include:

when the shape point P is selected₁Then obtain < P₁P₀P’₀If the angle value is greater than a preset first angle threshold value, then P is₁Is the starting point P₀Corresponding toStopping the shape point;

Optionally, the labeling position determining unit obtains, in the target road segment, a road segment where the to-be-labeled text of the road can be labeled, as a process of labeling a position of the to-be-labeled text of the road, and specifically may include:

Finally, it should also be noted that, herein, relational terms such as first and second, and the like may be used solely to distinguish one entity or action from another entity or action without necessarily requiring or implying any actual such relationship or order between such entities or actions. Also, the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising an … …" does not exclude the presence of other identical elements in a process, method, article, or apparatus that comprises the element.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the application. Thus, the present application is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the position of a road character label is characterized by comprising the following steps:

judging whether the geographical area range covered by the electronic map to be displayed is intersected with the geographical area range covered by the navigation route, if so, executing the following steps:

the reserved shape points form a shape point set of the road after rarefaction;

and determining the marking position of the characters to be marked of the road in the electronic map to be displayed according to the shape point set of the thinned road forming the navigation route.

2. The method of claim 1, wherein each shape point in the set of shape points is provided with a thinning-out flag, the method further comprising:

if the thinning mark is effective, thinning the selected shape point;

3. The method of claim 1, wherein obtaining the thinning-out skip point threshold of the road according to the map zoom level and the line width information of the road comprises:

4. The method according to any one of claims 1 to 3, wherein the determining of the marking position of the text to be marked of the road in the electronic map to be displayed according to the shape point set of the road forming the navigation route comprises:

5. The method according to claim 4, wherein the obtaining a continuous section of target shape points according to the positions of shape points in the shape point set of the road forming the navigation route, the target shape points forming a target road segment of the text to be labeled for labeling the road comprises:

calculating the length of the character to be marked;

6. The method according to claim 5, wherein sequentially searching shape points meeting a set zigzag condition from the starting point to the shape points of the candidate segment between the starting point and the adjacent end point thereof until searching the stop shape point corresponding to the starting point comprises:

when readIs a shape point P_iThe initial value of i is 2, and the angle P is acquired_iP_i-1P_i-2And < P_iP₀P’₀Each shape point i ═ i +1, P 'is selected'₀To be distinguished from P₀Another starting point of (a);

7. The method according to claim 5, wherein obtaining, in the target road segment, a road segment to be labeled with a text that can label the road comprises:

8. A road character marking position determining apparatus, comprising:

a marking position determining unit, configured to determine, when the intersection determination unit determines that the electronic map to be displayed is intersected, a marking position of a to-be-marked text of the road in the to-be-displayed electronic map according to a shape point set of the road included in a geographic area range covered by the to-be-displayed electronic map, the shape point set constituting the navigation route;

the rarefaction unit is used for determining a shape point set of the road, and specifically comprises:

9. The apparatus of claim 8, wherein each shape point in the shape point set is provided with a thinning mark, and the process of thinning the shape point set of the road by the thinning unit according to the map zoom level and the line width information of the road to obtain the thinned shape point set of the road further comprises:

if the thinning mark is effective, thinning the selected shape point;

10. The apparatus according to claim 8, wherein the process of obtaining the rarefaction trip point threshold of the road by the rarefaction unit according to the map zoom level and the line width information of the road specifically includes:

11. The apparatus according to any one of claims 8 to 10, wherein the process of determining the marked position of the text to be marked of the road in the electronic map to be displayed according to the shape point set of the road constituting the navigation route by the marked position determining unit specifically comprises:

12. The apparatus according to claim 11, wherein the labeling position determining unit obtains a continuous segment of target shape points according to positions of shape points in a set of shape points of a road constituting the navigation route, the target shape points constituting a process for labeling a target segment of a text to be labeled of the road, specifically comprising:

calculating the length of the character to be marked;

13. The apparatus according to claim 12, wherein the process of sequentially searching for shape points meeting the set meandering condition from the starting point to the shape points of the candidate segment between the starting point and the adjacent end point thereof until searching for the stop shape point corresponding to the starting point comprises:

14. The apparatus according to claim 12, wherein the process of acquiring, by the labeling position determining unit, the segment to be labeled with the text that can be labeled on the road in the target segment specifically includes: