JP2017102318A - Map display device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a map display device capable of preventing display of a character string from becoming awkward and difficult to read when a map image including the character string arranged along a specific shape is expanded.SOLUTION: A navigation device 1 is configured to display a map image including a character string arranged along a predetermined shape at a predetermined magnification, the character string consisting of characters spaced apart by a predetermined distance, and includes a shape expanding unit 146 configured to expand the predetermined shape associated with the character string at the predetermined magnification, and a character string rearrangement unit 148 configured to rearrange the character string such that each of the constituent characters keeps the predetermined distance therebetween along the predetermined shape expanded by the shape expanding unit 146.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a map display device that displays a map image including a character string such as a road name.

  Conventionally, a map display device that associates position coordinates of where each character constituting a character string such as a road name included in a map image is to be displayed and displays each character at the position of each coordinate Is known (for example, see Patent Document 1). This map display device realizes a natural and easy-to-read map display by changing the arrangement order of the character strings according to the angle of each character when the map image is rotated.

JP 2002-297025 A

  By the way, in the map display device disclosed in Patent Document 1 described above, since the position coordinates of each character constituting the character string are determined in advance, when the map image is enlarged, the interval between the characters also depends on the enlargement magnification. There is a problem that the character string becomes long and widened, the display becomes unnatural and the character string becomes difficult to read. In particular, when character strings are arranged along the shape of roads, etc., if you try to reduce the distance between the character strings that are extended when enlarged, the character strings will be inadvertently not aligned with the shape of the roads. It is not possible to improve the unnaturalness of the display by changing.

  The present invention was created in view of the above points, and its purpose is to display an unnatural image when a map image including a character string arranged along a specific shape is enlarged. An object of the present invention is to provide a map display device that can prevent a character string from becoming difficult to read.

  In order to solve the above-described problem, the map display device of the present invention displays a map image in which character strings each having a predetermined interval are arranged along a predetermined shape with a predetermined magnification. A map display device for enlarging a predetermined shape corresponding to a character string at an enlargement ratio, and maintaining a predetermined interval between each character constituting the predetermined shape after being enlarged by the shape enlargement unit And a character string rearranging means for arranging the character strings.

  As a result, even when the map image including the road is enlarged when the character string is arranged along the shape of the road or the like, the character string is enlarged along the shape of the enlarged road or the like before the enlargement. Can be rearranged at the same character spacing, and the character string is not extended, so that it is possible to prevent the display from becoming unnatural and the character string from becoming difficult to read.

  In addition, the character string rearranged along the predetermined shape after enlargement is re-entered within the section of the predetermined shape after expansion corresponding to the section sandwiched between the start point and end point of the character string in the predetermined shape before expansion. It is desirable to be arranged. Thereby, when the character string before expansion is arranged so as not to overlap with other character strings, the character string after expansion can be prevented from overlapping with other character strings.

  Further, it is desirable that the start point or end point of the character string rearranged along the predetermined shape after enlargement is arranged at a position corresponding to the start point or end point of the character string in the predetermined shape before enlargement. Thereby, the position of each character of the character string to be rearranged can be uniquely determined, and the processing can be simplified.

  Further, it is desirable that the predetermined shape before enlargement is set using a predetermined function. By approximating the predetermined shape as a function, the position of each character along the enlarged predetermined shape can be obtained by calculation.

  The predetermined function described above is preferably a polynomial of degree n. Thereby, the position calculation of each character along the predetermined shape after enlargement becomes easy, and the processing can be simplified.

It is a figure which shows the structure of the navigation apparatus of one Embodiment. It is a figure which shows the relationship between a reference | standard scale and display scales other than that. It is explanatory drawing of the rearrangement range of the character string after expansion. It is a figure which shows the detail of character string information. It is a flowchart which shows the operation | movement procedure which rearranges each character which comprises a character string at the time of expansion of a map image. It is explanatory drawing which arrange | positions the 2nd character after the character string.

  Hereinafter, a navigation device according to an embodiment to which a map display device of the present invention is applied will be described with reference to the drawings.

  FIG. 1 is a diagram illustrating a configuration of a navigation device according to an embodiment. The navigation device shown in FIG. 1 includes a navigation controller 1, a map data storage device 3, an operation unit 4, a vehicle position detection unit 5, a display device 6, and an audio unit 7. This navigation device is mounted on a vehicle.

  The navigation controller 1 implements various functions such as a map image display operation around the own vehicle position, a facility search operation, and a route search / guidance operation by executing a predetermined operation program using a CPU, ROM, RAM, and the like. . The detailed configuration of the navigation controller 1 will be described later.

  The map data storage device 3 is a storage medium that stores map data necessary for map display, facility search, route search, and the like and a reading device thereof. The map data storage device 3 stores map data in units of rectangular figure leaves divided into appropriate sizes by longitude and latitude. The map data of each leaf can be specified and read by designating the leaf number.

  This map data is represented by a coordinate set of points (nodes) expressed by longitude and latitude, and a road is formed by connecting two or more nodes, and a portion connecting two nodes is called a link. Map data includes road data for map matching and route search, including road lists, node tables, intersection configuration node lists, intersection net lists, etc., roads, parks, rivers, landmark buildings and facilities on the map screen, etc. It consists of background data for displaying various properties, administrative division names such as municipalities, road names, intersection names, characters such as building names, and character / symbol data for displaying map symbols.

  Of the various data constituting the map data, the data related to the present invention is character / symbol data, and the character / symbol data is arranged along a predetermined shape (for example, road shape, railway shape, river shape, etc.). The character string information for specifying the content / position of the character string to be processed is included. Details of the character string information will be described later.

  The map data storage device 3 is realized by a hard disk device or a semiconductor memory, or by a DVD and its reading device. Further, the map data storage device 3 may be replaced with a communication device to acquire map data from an external map distribution server (not shown).

  The operation unit 4 is for receiving user instructions (operations), and includes various operation buttons and operation knobs. In addition, the operation unit 4 includes a touch panel attached to the screen of the display device 6, and the user can directly perform an operation instruction by pointing a part on the screen with a finger or the like. Yes. The vehicle position detection unit 5 includes, for example, a GPS receiver, an orientation sensor, a distance sensor, and the like, detects the vehicle position (longitude, latitude) at a predetermined timing, and outputs a detection result.

  The display device 6 is composed of, for example, an LCD (liquid crystal display device), and is obtained by a map image around the vehicle position, an intersection guide image, or a facility search based on the video signal output from the navigation controller 1. A search result image including the facility and the surrounding parking lot is displayed. For example, the display device 6 is integrated with a housing of a navigation device arranged in the center of the dashboard or on the dashboard. The display device 6 may be separated from the casing of the navigation device and separated from the driver's legible position. The audio unit 7 outputs a guidance voice or the like generated based on the voice signal input from the navigation controller 1 into the vehicle interior.

  Next, a detailed configuration of the navigation controller 1 will be described. 1 includes a map buffer 10, a map readout control unit 12, a map drawing unit 14, a vehicle position calculation unit 20, a destination setting unit 22, a route search processing unit 24, a route guidance processing unit 26, and input processing. The unit 30 and the display processing unit 40 are included.

  The map buffer 10 temporarily stores map data read from the map data storage device 3. The map reading control unit 12 sends a request for reading a predetermined range of map data in accordance with the vehicle position calculated by the vehicle position calculating unit 20 and the position designated by the user by operating the operation unit 4. Output to. Based on the map data stored in the map buffer 10, the map drawing unit 14 performs drawing processing necessary for displaying a map image on the display device 6 to create map image drawing data. Details of the map drawing unit 14 will be described later.

  The vehicle position calculation unit 20 calculates the vehicle position based on the detection data output from the vehicle position detection unit 5, and if the calculated vehicle position is not on the road of the map data, the vehicle position is calculated. Perform map matching processing to correct.

  The destination setting unit 22 sets a destination for route search processing. For example, the destination setting unit 22 searches for a facility that satisfies the search condition specified by the user and sets it as the destination. The route search processing unit 24 searches for a travel route (guidance route) connecting the departure point and the destination (or waypoint) according to a predetermined search condition. The route guidance processing unit 26 creates guidance route drawing data for displaying the guidance route obtained by the search processing by the route search processing unit 24 so as to be superimposed on the map or displaying an enlarged view of the right / left turn intersection. Then, an audio signal such as intersection guidance necessary for guiding the vehicle along the guidance route is generated.

  The input processing unit 30 outputs commands for performing operations corresponding to various operation instructions input from the operation unit 4 to each unit in the navigation controller 1. The display processing unit 40 receives the map image drawing data created by the map drawing unit 14 and displays a predetermined range of map images on the screen of the display device 6 based on the drawing data.

  Next, details of the map drawing unit 14 will be described. As shown in FIG. 1, the map drawing unit 14 includes a background drawing unit 140 and a character / symbol drawing unit 142. In the present embodiment, it is assumed that the map image to be displayed is composed of a background image and characters, symbols, etc. that are displayed over the background image.

  The background drawing unit 140 draws a background image such as a sea, a lake, a forest, a rice field, a field, a building, a road, a railroad, and a river based on the background data included in the map data. The character / symbol drawing unit 142 is based on the character / symbol data included in the map data, such as road names, railroad names, river names, place names, building names, or map symbols arranged on the background image. Draw a string or symbol.

  In the present embodiment, the map image display scale is changed by enlarging a background image having a reference scale for a certain range. FIG. 2 is a diagram showing the relationship between the reference scale and other display scales. As shown in FIG. 2, when the display scale can be changed in a wide range from the wide area display to the detailed display, a plurality of reference scales A to G are set, and background data corresponding to each reference scale or Character / symbol data is available. There are various background data corresponding to each reference scale, such as a case where the background data is in a bitmap format or JPEG format, a case where polygon data and texture data are combined, and a case where these are combined. There is no particular limitation on the type of the above.

  Further, when displaying a background image of a display scale between adjacent reference scales, for example, between the reference scale C and the reference scale D, it is performed by enlarging the background image of the reference scale C on the smaller display scale. . Assuming that the display scale of the background image to be displayed is C ′, the background image may be enlarged at a magnification (C / C ′) of the background image of the reference scale C. Such background image enlargement is performed by the background drawing unit 140.

  In addition, the character strings and symbols are arranged on the enlarged background image without changing the size. In particular, for character strings arranged along roads and the like included in the background image before enlargement, the distance between the characters constituting the character string so as to follow the roads and the like included in the background image after enlargement Each character is rearranged so as not to spread (so as not to be spread out).

  The character / symbol drawing unit 142 includes an enlargement factor calculation unit 144, a shape enlargement unit 146, and a character string rearrangement unit 148 in order to rearrange the characters constituting the character string along such a predetermined shape. .

  When the display scale is changed, the enlargement ratio calculation unit 144 specifies a reference scale that is closest to the display scale after the change and is smaller than the display scale after the change, and calculates the ratio before and after the scale change as the enlargement ratio. To do. Considering the case of changing to the display scale C ′ described above, the closest reference scale smaller than the display scale C ′ is C, and the enlargement magnification (C / C ′) is calculated.

The shape enlarging unit 146 enlarges the predetermined shape corresponding to the character string at the enlargement magnification obtained by the calculation by the enlargement magnification calculating unit 144. The predetermined shape before expansion is set using a predetermined function, preferably a polynomial of degree n. For example, if the degree of a polynomial is n and the coefficients of each term of the polynomial are a _n , a _n-1 , a _n-2 ,..., A ₁ , a ₀ , this polynomial can be expressed as follows: it can.

a _n x _n + a _n-1 x _{n + 1} + a _n-2 x _{n + 2} + ... + a ₁ + a ₀ (1)
The character string rearrangement unit 148 arranges the character strings along the predetermined shape after being enlarged by the shape enlargement unit 146 such that each character constituting the image maintains the same predetermined interval as the character string before the enlargement. The character string rearranged along the predetermined shape after enlargement is rearranged in the section of the predetermined shape after expansion corresponding to the section sandwiched between the start point and end point of the character string in the predetermined shape before expansion. The Specifically, the start point or end point of the character string rearranged along the predetermined shape after enlargement is arranged at a position corresponding to the start point or end point of the character string in the predetermined shape before enlargement.

  FIG. 3 is an explanatory diagram of a rearranged range of character strings after enlargement. FIG. 3A shows an example in which a character string is arranged at an intermediate position in a section having a predetermined shape after enlargement. FIG. 3B shows an example in which the start points of the character strings are combined in a predetermined-shaped section before and after the enlargement. FIG. 3C shows an example in which the end points of the character strings are matched in a section having a predetermined shape before and after the enlargement.

  The above-described shape enlargement unit 146 corresponds to the shape enlargement unit, and the character string rearrangement unit 148 corresponds to the character string rearrangement unit.

  The navigation device of this embodiment has such a configuration, and the operation thereof will be described next.

FIG. 4 is a diagram showing details of the character string information. As shown in FIG. 4, the character string information includes “character string”, “reference scale arrangement start point”, “reference scale arrangement end point”, “degree of polynomial”, and “polynomial coefficient string”. . “Character string” is information for identifying each character constituting the character string, and includes a character code corresponding to each character. The “reference scale placement start point” indicates the position of the first character of the character string by coordinates on the map image of the reference scale. The “reference scale placement end point” indicates the position of the last character of the character string by coordinates on the map image of the reference scale. “Polynomial degree” is the degree n of a polynomial approximating a predetermined shape corresponding to a character string, and a specific number is set as the value of n. "Polynomial coefficients column" is a coefficient of each term of the polynomial of degree n, (1) coefficient a _n of the polynomial shown in the _{expression, a n-1, a n} -2, ···, is a _1, a ₀ included. For example, when n is 3, specific values of four coefficients a ₃ , a ₂ , a ₁ , and a ₀ are included.

  FIG. 5 is a flowchart showing an operation procedure for rearranging the characters constituting the character string when the map image is enlarged. This operation procedure is repeatedly performed at a cycle (for example, every 1/30 seconds) at which the display screen is updated. In addition, this operation procedure focuses on one character string arranged along a predetermined shape, and when there are a plurality of character strings arranged on the background image, the same applies to each character string. Is performed.

  First, the enlargement factor calculator 144 determines whether or not the display scale has been changed with respect to the reference scale (step 100). If it has been changed, a positive determination is made. Next, the enlargement factor calculator 144 calculates the enlargement factor of a predetermined shape corresponding to the character string based on the reference scale and the changed display scale (step 102). For example, in the example illustrated in FIG. 2, the magnification M (= C / C ′) is calculated based on the display scale C ′ and the reference scale C.

Next, the shape enlargement unit 146 enlarges the predetermined shape corresponding to the character string with the enlargement magnification M calculated in step 102 (step 104). For example, assuming that equation (1) is f (x) and a predetermined shape is approximated using this function f (x), the coordinates (x, y) of each character string in the display image of the reference scale are as follows:
y = f (x) (2)
Can be calculated with In order to make the function f (x) as simple as possible, each character of the character string is arranged so that both the reference scale arrangement start point and the reference scale arrangement end point are arranged on the X axis (horizontal axis). After rotating the position and replacing the reference scale arrangement start point with the coordinate origin (0, 0), the function f (x) in the equation (2) is defined. Therefore, after the coordinates (x, y) of each character are finally obtained by calculation, the position of each character is rotated again in the opposite direction, and the coordinates of the reference scale placement start point are replaced with the origin. Coordinate conversion for returning is necessary, but in order to simplify the explanation, explanation of these operations is omitted.

When the predetermined shape approximated by the function expressed by the equation (2) is multiplied by M in the x-axis direction and the y-axis direction, the coordinates (x, y) of the position along the predetermined shape after expansion are
y = M × f (x / M) (3)
Can be calculated with

  Next, the character string rearrangement unit 148 determines an arrangement along a predetermined shape for the first character of the character string (step 106). Note that, in the case shown in FIG. 3B (when the start point of the character string is matched in the section of the predetermined shape before and after the enlargement), the position of the origin (0, 0) that is one end of the predetermined shape after the expansion Is the position of the first character (first character) of the character string.

  Next, the character string rearrangement unit 148 determines a position along the predetermined shape for the second character of the character string (step 108).

  FIG. 6 is an explanatory diagram for arranging the second and subsequent characters of the character string. In FIG. 6, P1 indicates the center position of the first character arrangement, and T1 indicates the display range of the first character in the character string. Each character is provided with a frame W for designating the center position of adjacent characters that can be arranged without overlapping each other. The character string rearrangement unit 148 sets the position P2 where the frame W set corresponding to the first character and the enlarged function M × f (x / M) intersect at the center of the second character position. Set to position. The procedure for determining the positions of adjacent characters in this way is not only when placing a character string along a predetermined shape after enlargement, but also when placing a character string along a predetermined shape before enlargement. As a result, the interval between the characters constituting the character string before and after the enlargement can be made the same.

  Next, the character string rearrangement unit 148 determines whether or not there is a next character (step 110). If the third and subsequent characters are present, an affirmative determination is made. Next, the character string rearrangement unit 148 determines the position of the next character in the same manner as the procedure for determining the arrangement of the second character (step 112). Thereafter, returning to step 110, the operations after the determination of the presence / absence of the next character are repeated.

  When the positions of all the characters constituting the character string are determined, a negative determination is made in the determination in step 110, and the rearrangement operation of the character strings along the enlarged predetermined shape included in the enlarged map image is completed. .

  If the reference scale map image display is performed without changing the display scale, a negative determination is made in the determination of step 100, and the predetermined shape is not enlarged in steps 102 and 104, and step 106 is immediately performed. Migrate to In this case, the character string is configured using the function (f (x)) corresponding to the predetermined shape before enlargement, instead of the function (M × f (x / M)) corresponding to the predetermined shape after enlargement. What is necessary is just to arrange each character.

  As described above, in the navigation device of the present embodiment, even when a map image including a road or the like is enlarged when a character string is arranged along the shape of the road or the like, the shape of the enlarged road or the like The character string can be rearranged at the same character spacing as before enlargement, and the character string will not be extended, thereby preventing the display from becoming unnatural and difficult to read. it can.

  In addition, the character string rearranged along the predetermined shape after the enlargement is rearranged in the section of the predetermined shape after the expansion corresponding to the section sandwiched between the start point and the end point of the character string in the predetermined shape before the expansion. By arranging (FIG. 3A), when the character string before enlargement is arranged so as not to overlap with other character strings, the character string after enlargement may also be prevented from overlapping with other character strings. it can.

  Further, the start point or end point of the character string rearranged along the predetermined shape after enlargement is arranged at a position corresponding to the start point or end point of the character string in the predetermined shape before enlargement (FIG. 3). (B), (C)), the position of each character in the rearranged character string can be uniquely determined, and the processing can be simplified.

  Further, by approximating the predetermined shape before enlargement corresponding to the character string by a function, the position of each character along the predetermined shape after enlargement can be obtained by calculation. Further, by making this function a polynomial of degree n, it becomes easy to calculate the position of each character along a predetermined shape after enlargement, and the processing can be simplified.

  In addition, this invention is not limited to the said embodiment, A various deformation | transformation implementation is possible within the range of the summary of this invention. For example, in the above-described embodiment, when the map image is enlarged, the order of the characters constituting the character string is maintained. However, when the map image is displayed with heading up, the map image is displayed together with the vehicle direction. In the case of rotation, the order of the character strings may be changed as necessary so that the character strings can be read from left to right or from top to bottom. Even in such a case, the present invention can be applied because there is no change in the operation itself of rearranging the characters constituting the character string along the enlarged predetermined shape.

  In the embodiment described above, the present invention is applied to a navigation device mounted on a vehicle. However, when a map image is enlarged in a map application executed by a mobile terminal device, or a map is executed in a map application executed by a personal computer or the like. The present invention can also be applied to the case of enlarging an image.

  As described above, according to the present invention, when a character string is arranged along the shape of a road or the like, even if the map image including the road or the like is enlarged, the shape of the enlarged road or the like is obtained. The character string can be rearranged at the same character spacing as before the enlargement, and the character string is not extended, so that it is possible to prevent the display from becoming unnatural and difficult to read. .

DESCRIPTION OF SYMBOLS 1 Navigation controller 3 Map data storage device 6 Display apparatus 10 Map buffer 12 Map reading control part 14 Map drawing part 20 Vehicle position calculation part 40 Display processing part 140 Background drawing part 142 Character / symbol drawing part 144 Enlargement magnification calculation part 146 Shape expansion Part 148 Character string rearrangement part

Claims (5)

A character string having a predetermined interval between each character constituting a map display device that displays an enlarged map image arranged at a predetermined magnification at a predetermined magnification,
Shape enlarging means for enlarging the predetermined shape corresponding to the character string at the enlargement magnification;
A character string rearrangement unit that arranges the character string so that each character constituting the character string maintains the predetermined interval along the predetermined shape after being enlarged by the shape enlargement unit;
A map display device comprising: In claim 1,
The character string to be rearranged along the predetermined shape after expansion is a section of the predetermined shape after expansion corresponding to a section sandwiched between the start point and end point of the character string in the predetermined shape before expansion A map display device characterized by being rearranged inside. In claim 1 or 2,
The start point or end point of the character string to be rearranged along the predetermined shape after enlargement is arranged at a position corresponding to the start point or end point of the character string in the predetermined shape before enlargement. A featured map display device. In any one of Claims 1-3,
The map display device, wherein the predetermined shape before the enlargement is set using a predetermined function. In claim 4,
The map display device, wherein the predetermined function is a polynomial of degree n.

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