JP2009258316A - Map display apparatus, map display method, map display program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a structure wherein, when displaying map information properly in accordance with the actual distance, processing can be efficiently performed by a simple operation. <P>SOLUTION: In a map display apparatus 10, an own vehicle position information receiving section 11 receives the present position information of a vehicle, and a map information acquisition section 12 acquires the map information. A latitude direction length calculation section 13 specifies a drawing object area in the acquired map information and, on the basis of latitude information and longitude information of a prescribed position in the drawing object area, calculates the proportion of the actual length in the latitude direction to the actual length in the longitude direction. Further, in accordance with this proportion, the latitude direction length calculation section 13 calculates the proportion of the length in the latitude direction so that the proportion of the actual length in latitude direction and that in longitude direction becomes 1:1 on the basis of the length in longitude direction. Then, a map information output section 15 adjusts the length in the latitude direction of the drawing area in the map information acquired by the map information acquisition section 12 on the basis of the calculated proportion of the length in latitude direction, and outputs the map information after the adjustment. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a display technology for displaying map information on a display unit, and more particularly, a map display device that can efficiently process by simple calculation when displaying map information appropriately according to an actual distance. And a map display method and a computer program for map display.

  As a map information output display device, a car navigation device (hereinafter referred to as “car navigation”) is known. Most of the map information used in this car navigation system is managed by dividing a predetermined area on the earth into rectangular ranges (hereinafter referred to as “mesh”) divided by a certain latitude width and longitude width. Etc. are expressed by numerical values of latitude and longitude. For example, in JIS (Japanese Industrial Standards), an area (about 80 × 80 km) with a latitude width of 1 degree and a longitude width of 40 minutes corresponding to the range of the map division of the 1 / 200,000 topographic map is defined as a primary mesh, An area (approximately 10 × 10 km) having a latitude width of 5 minutes and a longitude width of 7 minutes 30 seconds corresponding to the range of the map of the 1 / 25,000 topographic map is defined as a secondary mesh.

  However, since the earth is a sphere, when it is drawn in a plane, distortion occurs and the area, angle, distance, etc. cannot be displayed correctly. That is, the longitude range differs between the high latitude region and the low latitude region, and when drawn in a plane, the length in the latitude direction is almost constant, but the length in the longitude direction goes from the low latitude region to the high latitude region. The ratio of the actual length to the longitude width varies depending on the latitude.

The fact that the longitude width varies depending on the latitude can be described with reference to FIG. 9, for example. FIG. 9 is a schematic diagram showing the relationship between the width in the latitude direction and the width in the longitude direction.
In FIG. 9, symbol A1 indicates the latitude width in the low latitude region, symbol A2 indicates the latitude width in the middle latitude region, symbol A3 indicates the latitude width in the high latitude region, and the relationship between these latitude widths is A1≈ A2≈A3, which indicates that the length (distance) is almost constant. On the other hand, in FIG. 9, the symbol B1 indicates the longitude width in the low latitude region, the symbol B2 indicates the longitude width in the middle latitude region, the symbol B3 indicates the longitude width in the high latitude region, and the relationship between these longitude widths is B1>B2> B3, indicating that the length (distance) gradually decreases.

Therefore, when displaying map information managed by a mesh with a constant latitude / longitude width, the actual length differs depending on the latitude even if the mesh has the same longitude width. The length in the latitudinal direction will be displayed in a short state.
Map information managed by a mesh having a constant latitude / longitude width can be described with reference to FIG. 10, for example. FIG. 10 is a schematic diagram illustrating a map information management method.
FIG. 10A shows map information M1 in which a predetermined area in a low latitude area indicated by a latitude width A1 and a longitude width B1 is managed by normalization with a constant mesh having an aspect ratio of 1: 1. Yes. In FIG. 10B, the predetermined area in the middle latitude area indicated by the latitude width A2 and the longitude width B2 is normalized and managed with a constant mesh having an aspect ratio of 1: 1 by extending the longitude width B2. The map information M2 being displayed is shown. Further, in FIG. 10C, a predetermined area in the high latitude area indicated by the latitude width A3 and the longitude width B3 is managed by normalizing with a constant mesh having an aspect ratio of 1: 1 by extending the longitude width B3. Map information M3 is shown.

Therefore, although the road displayed based on such map information is actually an orthogonal road, depending on the latitude, the road is displayed with a crushed feeling of intersecting obliquely. The state of the road displayed with such a collapsed feeling can be described with reference to FIG. 11, for example. FIG. 11 is a schematic diagram showing a road state displayed by a conventional map display device.
In FIG. 11, when a road L10 and a road L20 are orthogonal to each other in a predetermined region in a high latitude area indicated by a latitude width A3 and a longitude width B3, when normalized and managed with a fixed mesh having an aspect ratio of 1: 1, It is shown that the road L10 and the road L20 that are orthogonal to each other are actually stored in a state where they intersect obliquely with a collapsed feeling by extending the longitude width B3.

In view of this, several means for appropriately displaying map information according to actual distances have been proposed.
For example, based on a coordinate system in which the earth axis is virtually tilted so that a high latitude area becomes a relatively low latitude area, map data is created in units of rectangular areas based on a certain longitude width. There is known one that draws a map to be used and displayed (for example, see Patent Document 1).
In addition, a temporary equator is set, map data of a figure having a predetermined longitude width and latitude width is created based on the longitude and latitude specified by the temporary equator, and a map to be displayed is drawn using the map data. Those are known (for example, see Patent Document 2).
JP 2002-351307 A JP 2003-84665 A

However, both of the technologies described in Patent Documents 1 and 2 described above create predetermined map data in advance, and require very complicated processing in creating this map data. Therefore, the map information is not appropriately displayed according to the actual distance quickly while using the map information managed by the mesh having a constant latitude width / longitude width.
Thus, when displaying map information appropriately according to actual distance, the means which can be processed efficiently by simple calculation is not proposed at present.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a mechanism that allows efficient processing by simple calculation when map information is appropriately displayed according to an actual distance. .

  The map display device of the present invention is a map display device that appropriately displays map information according to actual distance, and divides the map information into rectangular ranges separated by a certain latitude width and longitude width. First storage means for storing map information, own vehicle position information receiving means for receiving vehicle current position information, and the first storage based on the current position information of the vehicle received by the own vehicle position information receiving means. A map information acquisition means for acquiring map information from the means, and a drawing target area in the map information acquired by the map information acquisition means based on the current position information of the vehicle received by the own vehicle position information reception means; Based on the latitude information and longitude information of the predetermined position in the specified drawing target area, the ratio of the actual length in the latitude direction and the actual length in the longitude direction is calculated, and further, based on this ratio, the longitude Latitudinal length calculation means for calculating a ratio of the length in the latitudinal direction so that the ratio of the actual length in the latitudinal direction and the actual length in the longitude direction is 1: 1 with reference to the length in the direction; Based on the ratio of the length in the latitude direction calculated by the length calculation means in the latitude direction, the length in the latitude direction of the drawing area in the map information acquired by the map information acquisition means is adjusted, and the map after adjustment Map information output means for outputting information.

  Further, in the map display device of the present invention, the latitude direction length calculating means obtains latitude information with the longitudinal center position of the specified drawing target area as a predetermined position, and the longitude direction is based on the value of the latitude information It is also possible to calculate the ratio of the actual length in the latitude direction and the actual length in the longitude direction.

  In the map display device of the present invention, the latitude direction length calculation unit may repeatedly update the calculation of the ratio of the length in the latitude direction every time the latitude information changes by 1/8 degree.

  In addition, the map display method of the present invention includes first storage means for storing map information divided into rectangular ranges divided by a constant latitude width and longitude width, and the map information is actually displayed by the map display device. A map display method for appropriately displaying according to the distance of the vehicle, the first step of receiving the current position information of the vehicle, and the current position of the vehicle received in the first step in the map display device A second step of acquiring map information from the first storage means based on information, and a map acquired by the map information acquisition means based on the current position information of the vehicle received in the first step in the map display device; The drawing target area in the information is specified, and based on the latitude information and the longitude information at a predetermined position in the specified drawing target area, the actual length in the latitude direction and the actual longitude direction Further, based on this ratio, the ratio between the actual length in the latitude direction and the actual length in the longitude direction is 1: 1 based on the length in the longitude direction. Based on the ratio of the length in the latitude direction calculated in the third step and the length ratio in the latitude direction calculated in the third step, the length in the latitude direction of the drawing area in the map information acquired in the second step is calculated. And 4 steps of outputting the adjusted map information from the map display device.

  In the map display method of the present invention, the third step obtains latitude information with the vertical center position of the drawing target area specified in the third step as a predetermined position, and the latitude information is based on the value of the latitude information. The actual length in the longitude direction may be calculated, and the ratio between the actual length in the latitude direction and the actual length in the longitude direction may be calculated.

  In the map display method of the present invention, the third step may repeatedly update the calculation of the ratio of the length in the latitude direction every time the latitude information changes by 1/8 degree.

  Further, the map display program of the present invention comprises first storage means for storing map information by dividing it into a rectangular range divided by a constant latitude width and longitude width, and the map information according to the actual distance. In order to appropriately display the computer, the means for receiving the current position information of the vehicle, the means for acquiring the map information from the first storage means based on the received current position information of the vehicle, the received the The drawing target area in the map information acquired based on the current position information of the vehicle is specified, and the actual length in the latitude direction and the actual longitude direction are determined based on the latitude information and longitude information at the predetermined position in the specified drawing target area. Based on this ratio, the ratio of the actual length in the latitude direction to the actual length in the longitude direction is 1: Means for calculating the ratio of the length in the latitudinal direction to adjust the length in the latitudinal direction of the drawing area in the acquired map information based on the calculated ratio of the length in the latitudinal direction, and after adjustment It is made to function as a means to output the said map information.

  Further, the map display program of the present invention obtains latitude information by using the computer as a predetermined position at the longitudinal center position of the specified drawing target area, and based on the value of the latitude information, the actual length in the longitude direction is obtained. And a means for calculating a ratio between the actual length in the latitude direction and the actual length in the longitude direction may be further functioned.

  Furthermore, the map display program of the present invention may further cause the computer to function as means for repeatedly updating the calculation of the ratio of the length in the latitude direction every time the latitude information changes by 1/8 degree. .

The map display device of the present invention specifies a drawing target area in map information, and based on latitude information and longitude information at a predetermined position in the drawing target area, a ratio between an actual length in the latitude direction and an actual length in the longitude direction Further, based on this ratio, the length in the latitude direction is set so that the ratio between the actual length in the latitude direction and the actual length in the longitude direction is 1: 1 with reference to the length in the longitude direction. Means for calculating the ratio. Therefore, when the current position information of the vehicle is received and the map information is acquired based on the position information, this means allows the vertical (latitude) direction in the map information according to the latitude with reference to the horizontal (longitude) direction. The length can be adjusted and displayed as a constant length in the vertical and horizontal directions.
Therefore, when displaying map information appropriately according to the actual distance (length), it is possible to provide a mechanism that can be processed efficiently by a simple calculation.

Hereinafter, an example of a map display device, a map display method, and a map display computer program according to the present invention will be described with reference to the drawings.
A map display device (hereinafter referred to as “this device”) 10 according to the present invention is a device that appropriately displays map information according to an actual distance.

FIG. 1 is a schematic diagram illustrating an example of a map display system (hereinafter referred to as “the present system”) using the apparatus 10, and FIG. 2 is realized by using the apparatus 10 for a map information display system. It is the schematic which shows a map information output device.
As shown in FIG. 1, the present system can be configured by the present device 10, the own vehicle position positioning device 20, the display unit 20, and the input unit 30.

The own vehicle position measuring device 20 is a device that measures the current position of the vehicle, receives a GPS signal transmitted from a GPS satellite, measures a position based on the GPS signal, It consists of a speed sensor that measures the amount of movement (distance), a gyro sensor that measures the traveling (movement) direction, and the like.
A GPS sensor is a so-called GPS receiver, receives a GPS signal radiated from a GPS satellite, measures a distance (pseudo distance) between the GPS satellite and the GPS receiver itself, and receives a plurality of satellites. Are simultaneously received to calculate the current position (GPS positioning solution) of the GPS receiver itself.
In addition, the vehicle positioning device 20 is mounted on a vehicle, and performs processing such as decoding of the received GPS signal in addition to a GPS receiver (antenna) that receives the GPS signal, and signal processing that is output to the device 10 A part.

The display unit 30 is a device that displays the map information output from the device 10, and is a so-called display (or monitor). The display unit 30 may be provided exclusively for the apparatus 10 or may be provided in the map information output apparatus 1 and use a display area.
The input unit 40 is an input device that gives various instructions to the device 10, and is an operation button that arbitrarily changes the map area displayed on the display unit 30.

Next, the map information output device 1 realized by using this system will be described.
In FIG. 2, an input unit 40 is stacked on the display unit 30. In the present embodiment, the input unit 40 includes a command input button that detects selection on the display unit 30.
In FIG. 2, the display unit 30 includes an up button 41U for moving up the map area displayed on the display unit 30, a down button 41D for moving down the map area, and the map area. A right movement button 41R that moves to the right and a left movement button 41L that moves the map area to the left are configured.

Next, the configuration of the apparatus 10 will be described.
FIG. 2 is a block diagram illustrating an example of the apparatus 10.
As shown in FIG. 2, the device 10 includes a map information storage unit F1, a vehicle position information reception unit 11, a map information acquisition unit 12, a latitude length calculation unit 13, and a map information output unit 14. , And a control unit 15. Reference numeral 16 in the figure denotes a bus for transmitting control signals, data, and the like in the apparatus 10.

The apparatus 10 may be an information processing apparatus, and is realized by, for example, a mobile personal computer, a PND (Portable Navigation Device), a dedicated device, a mobile phone, or the like. Although not shown, the apparatus 10 includes a CPU (Central Processing Unit), a program storage unit, an OS (Operating System), and the like.
The CPU is means for controlling and controlling each component of the apparatus 10 and executing program processing according to the computer program stored in the program storage unit. The program storage unit is constituted by a ROM (Read Only Memory), a RAM (Random Access Memory), or the like, and is a means for storing various computer programs used by the apparatus 10.

The map information storage unit F1 is means for storing map information by dividing it into a rectangular range (hereinafter referred to as “mesh”) divided by a certain latitude width and longitude width.
The map information may be stored in advance in the storage unit of the map information output device 1. In addition to being stored in the storage unit of the device 10 or the map information output device 1, for example, it is stored in an auxiliary storage device as a removable medium called a so-called SD memory card, a CD-ROM, a DVD-ROM or the like. Can do. Further, it may be downloaded via a communication network such as the Internet.

The own vehicle position information receiving unit 11 performs a process of receiving the current position information of the vehicle. That is, the current position information of the vehicle measured by the own vehicle position measuring device 20 is acquired.
The current vehicle position information received by the vehicle position information receiving unit 11 is transmitted to the map information acquiring unit 12 and the latitude length calculating unit 13.

The map information acquisition unit 12 performs a process of acquiring map information from the map information storage unit F <b> 1 based on the current vehicle position information received by the vehicle position information reception unit 11.
The map information acquired by the map information acquisition unit 12 is transmitted to the latitude direction length calculation unit 13 and the map information output unit 14.

  The latitude direction length calculation unit 13 specifies the drawing target area in the map information acquired by the map information acquisition unit 12 based on the current position information of the vehicle received by the own vehicle position information receiving unit 11, and specifies the specified drawing target area. Based on the latitude information and longitude information of the predetermined position in, calculate the ratio of the actual length in the latitude direction and the actual length in the longitude direction, and based on this ratio, the length in the longitude direction as a reference The ratio of the length in the latitude direction is calculated so that the ratio between the actual length in the latitude direction and the actual length in the longitude direction is 1: 1. That is, the latitudinal length calculation unit 13 adjusts a so-called aspect ratio in the map information in a mesh divided by a certain latitude width and longitude width.

  Here, the ratio between the actual length in the latitude direction and the actual length in the longitude direction has the radius of the earth as a fixed value, and from the latitude information value, the actual length in the latitude direction and the actual length in the longitude direction Is calculated by a trigonometric function and then calculated based on the actual lengths in the latitude and longitude directions.

Further, the latitude direction length calculation unit 13 obtains latitude information with the vertical center position of the specified drawing target region as a predetermined position, calculates the actual length in the longitude direction based on the value of the latitude information, It may have a function of calculating the ratio of the actual length in the direction and the actual length in the longitude direction.
Here, the vertical center position of the drawing target area refers to the latitude center position of the drawing area displayed on the display unit, that is, the vehicle position. Thereby, the distortion of the center part in the map information displayed on the display part can be reduced.

  The map information output unit 14 adjusts the length in the latitude direction of the drawing area in the map information acquired by the map information acquisition unit 12 based on the ratio of the length in the latitude direction calculated by the latitude direction length calculation unit 13, Processing to output the map information after adjustment. That is, the number of dots in which the normalized map information is drawn is varied only in the vertical (latitude) direction, and the map information is adjusted and output so as to be appropriately displayed according to the actual distance.

  The control unit 15 includes a CPU, a ROM, a RAM, and the like. The control unit 15 controls each component of the apparatus 10 and executes the process.

<First Embodiment>
Next, an example of operation | movement of this apparatus 10 which implements the map display method based on this invention is demonstrated, referring FIG. FIG. 4 is a flowchart showing an example of the map display process in the apparatus 10.
First, the vehicle position information receiving unit 11 receives the current position information of the vehicle (S10).
Next, the map information acquisition unit 12 acquires the map information of the corresponding area from the map information storage unit F1 based on the current vehicle position information received by the host vehicle position information reception unit 11 (S20).

Moreover, the latitude direction length calculation part 13 specifies the drawing object area | region in the map information acquired by the map information acquisition part 12 based on the present position information of the vehicle received by the own vehicle position information reception part 11 (S30).
Subsequently, the latitude direction length calculation unit 13 calculates the ratio of the actual length in the latitude direction and the actual length in the longitude direction based on the latitude information and the longitude information at the predetermined position in the specified drawing target area (S40). ). The ratio of the actual length in the latitude direction and the actual length in the longitude direction is calculated by using the trigonometric function to calculate the actual length in the latitude direction and the actual length in the longitude direction from the value of the latitude information. Is calculated based on the actual length of and the actual length in the longitude direction. Here, the earth is regarded as a sphere, and the actual length in the latitude direction and the actual length in the longitude direction are simply calculated based on the value of the latitude information, but the calculation is based on the Bessel ellipsoid. It is also good.

Further, the predetermined position here can be a center position 31 in the latitudinal direction of the drawing area displayed on the display unit 30, as shown in FIG. In FIG. 7, the center position 31 in the latitudinal direction indicates a case where the map information is displayed with the north facing reference.
As a result, the ratio is calculated based on the center portion of the drawing area that the user often sees, and the map information is displayed appropriately according to the actual distance (length) with little distortion in the center portion. .

  Next, the ratio of the actual length in the latitude direction and the actual length in the longitude direction on the basis of the length in the longitude direction based on the ratio of the actual length calculated by the latitude direction length calculation unit 13 The ratio of the length in the latitude direction is calculated so that becomes 1: 1 (S50). That is, the horizontal (longitude) direction is constant and the vertical (latitude) direction is variable.

Further, the map information output unit 14 adjusts the length in the latitude direction of the drawing area in the map information acquired by the map information acquisition unit 12 based on the ratio of the length in the latitude direction calculated by the latitude direction length calculation unit 13. (S60). Thereby, although drawing for each time displays the whole drawing area in the same ratio, it adjusts how many dots the map information normalized according to the latitude is drawn.
Here, the adjustment of the length of the drawing area in the latitude direction in the map information described above can be shown, for example, in FIG.
FIG. 5 is a schematic diagram showing that the length of the map information in the latitude direction is adjusted by this apparatus. In FIG. 5A, map information M1 managed with a constant mesh having an aspect ratio of 1: 1 is appropriately displayed as map information indicated by latitude width A1 and longitude width B1 according to the actual distance. ing. In FIG. 5B, map information M2 managed with a constant mesh having an aspect ratio of 1: 1 is a latitude width A2 obtained by extending the length of the drawing area in the latitude direction according to the actual distance. It is appropriately displayed as the map information indicated by the longitude width B2. Further, in FIG. 5C, the map information M3 managed by a constant mesh having an aspect ratio of 1: 1 is a latitude width A3 obtained by extending the length of the drawing area in the latitude direction according to the actual distance. It is appropriately displayed as the map information indicated by the longitude width B3.

  The magnification of the length (latitude) direction of the drawing area adjusted as described above is specifically 1.112602 in Okinawa with a latitude of 26 °, for example, and 1.100602 in Hokkaido with a latitude of 45 °. 414214. Therefore, in Okinawa, the horizontal (longitude) length of the map information is set to 1, and the vertical (latitude) length is adjusted to be 1.112602 times. In Hokkaido, the horizontal (longitude) of the map information is drawn. And the length (latitude) is adjusted to be extended by 1.414214 times, and the image is drawn.

Then, the map information output unit 14 outputs the adjusted map information to the display unit (S70).
Thereby, a series of operation | movement with this apparatus 10 is complete | finished.
Here, the map information after adjustment can be shown, for example, in FIG. FIG. 6 is a schematic diagram showing a road state displayed by the present apparatus.
In FIG. 6, the map information having the road L10 and the road L20 which are managed in a state where they intersect with each other in a predetermined direction indicated by the latitude width A3 and the longitude width B3 while being orthogonal to each other but being crushed is an aspect ratio of 1. When managed with a constant mesh M3 of 1: 1, the latitude width A3 is expanded on the basis of the longitude width B3 so that the actual length in the vertical and horizontal directions is 1: 1. It is shown that the road L10 and the road L20 are displayed as they are in an actual state orthogonal to each other.

As described above, in the present embodiment, map information managed by a mesh having a constant latitude width / longitude width is obtained by actually calculating vertical (latitude) and horizontal (longitude) directions by simple calculation using a determinant. The length is displayed as constant. Therefore, it is possible to quickly provide map information to be appropriately displayed according to the actual distance without requiring complicated processing.
That is, in the present invention, when adjusting the map information, the horizontal (longitude) length is not changed, and the length (latitude) length magnification is set to 1 / cos (longitude). Therefore, when a very high specification is not required, it is possible to efficiently perform the process of appropriately displaying the map information according to the actual distance by a simple calculation.

<Second Embodiment>
Further, in the present invention, the calculation of the ratio of the length in the latitude direction can be adjusted so that the adjustment of the map information is visually smooth. That is, it differs from the first embodiment described above in that it has a function of repeatedly updating the ratio of the length in the latitude direction every time the latitude information changes by 1/8 degree. In other embodiments described below, the description will focus on parts that are different from the first embodiment described above. Therefore, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. Unless otherwise specified, the same components are assumed to be the same.
Hereinafter, an example of the process will be described with reference to FIG.
FIG. 8 is a flowchart showing another example of the map display process in the apparatus 10.

  First, the own vehicle position information receiving unit 11 receives the current position information of the vehicle, the map information acquiring unit 12 acquires map information of the corresponding area based on the received current position information of the vehicle, and the latitude direction length calculating unit 13 specifies a drawing target area in the map information based on the current position information of the vehicle, and based on latitude information and longitude information at a predetermined position in the drawing target area, the actual length in the latitude direction and the actual length in the longitude direction Calculate the ratio. Further, the ratio of the actual length in the latitude direction and the actual length in the longitude direction is determined based on the length in the longitude direction based on the ratio of the actual length calculated by the latitude direction length calculation unit 13. The ratio of the length in the latitude direction is calculated to be 1: 1, and the map information output unit 14 further calculates the length in the latitude direction of the drawing area in the map information based on the calculated ratio of the length in the latitude direction. Adjust. And the process so far that the map information output part 14 outputs the adjusted map information to a display part (S70) is the same as that of the case of 1st Embodiment mentioned above.

Next, the own vehicle position information receiving unit 11 receives the current position information of the vehicle again (S80).
Further, the map information acquisition unit 12 determines whether there is a change in the map information based on the received current position information of the vehicle (S90).
As a result, when the map information acquisition unit 12 determines that there is a change in the map information (Y), the map information acquisition unit 12 re-acquires the map information of the corresponding region (S100).
Then, the latitude direction length calculation part 13 specifies the drawing object area | region in map information based on the present position information of this vehicle (S110).
On the other hand, when the map information acquisition unit 12 determines that there is no change in the map information (N), the latitude length calculation unit 13 continues to specify the drawing target area in the map information based on the current position information of the vehicle. (S110).

Further, the latitude direction length calculation unit 13 determines whether or not the latitude information has changed by 1/8 degrees (S120).
As a result, when the latitude direction length calculation unit 13 determines that the latitude information has changed by 1/8 degree (Y), based on the latitude information and the longitude information at a predetermined position in the drawing target region, the actual latitude direction is calculated. A ratio between the length and the actual length in the longitude direction is calculated (S130).
On the other hand, when the latitude direction length calculation unit 13 determines that the latitude information has not changed by 1/8 degrees (N), the map information output unit 14 calculates the map based on the calculated ratio of the length in the latitude direction. The length in the latitude direction of the drawing area in the information is readjusted (S150).

In addition, after the latitude length calculation unit 13 calculates the ratio of the actual length in the latitude direction and the actual length in the longitude direction, the latitude direction length calculation unit 13 further calculates the actual length calculated. Based on the ratio, the ratio of the length in the latitude direction is recalculated so that the ratio between the actual length in the latitude direction and the actual length in the longitude direction is 1: 1 with reference to the length in the longitude direction. (S140).
And the map information output part 14 readjusts the length of the latitude direction of the drawing area in map information based on the ratio of the length of the recalculated latitude direction (S150).
Thereafter, the map information output unit 14 outputs the map information after readjustment to the display unit (S160).

As described above, in the present embodiment, the adjustment timing can be controlled so that the map information is not frequently adjusted while the vehicle is moving.
Therefore, even if the device has a low specification, the map information is adjusted so that the vertical (latitude) length can be smoothly displayed according to the latitude without any apparent discomfort.

  INDUSTRIAL APPLICABILITY The present invention is industrially useful in the industry that handles devices that display map information, and is also useful in the electronic product market such as electronic map software using GPS (Global Positioning System) and car navigation devices. .

It is a block diagram which shows an example of the map display system using the map display apparatus which concerns on this invention. It is the schematic which shows the map information output device implement | achieved by using the map display apparatus which concerns on this invention for a map information display system. It is a block block diagram which shows an example of embodiment of the map display apparatus which concerns on this invention. It is a flowchart which shows an example of the map display process in the map display apparatus which concerns on this invention. It is a schematic diagram which shows that the length of the latitude direction of map information is adjusted with the map display apparatus which concerns on this invention. It is a schematic diagram which shows the state of the road displayed by the map display apparatus which concerns on this invention. It is a schematic diagram which shows the predetermined position used as the reference | standard which adjusts the length of the latitude direction in the map display apparatus which concerns on this invention. It is a flowchart which shows another example of the map display process in the map display apparatus which concerns on this invention. It is a schematic diagram which shows the relationship between the width | variety of a latitude direction, and the width | variety of a longitude direction. It is a schematic diagram explaining the management method of map information. It is a schematic diagram which shows the state of the road displayed by the conventional map display apparatus.

Explanation of symbols

  F1 map information file, 10 map display device, 11 own vehicle position information reception unit, 12 map information acquisition unit, 13 latitude direction length calculation unit, 14 map information output unit, 15 control unit, 20 own vehicle position positioning device, 30 Display unit, 40 input unit.

Claims (9)

A map display device that appropriately displays map information according to an actual distance,
First storage means for storing map information divided into rectangular ranges delimited by a constant latitude width and longitude width;
Own vehicle position information receiving means for receiving the current position information of the vehicle;
Map information acquisition means for acquiring map information from the first storage means based on the current position information of the vehicle received by the vehicle position information reception means;
While specifying the drawing target area in the map information acquired by the map information acquisition means based on the current position information of the vehicle received by the own vehicle position information receiving means, latitude information of a predetermined position in the specified drawing target area; Based on the longitude information, calculate the ratio between the actual length in the latitude direction and the actual length in the longitude direction, and based on this ratio, the actual length in the latitude direction based on the length in the longitude direction And a latitude length calculation means for calculating a ratio of the length in the latitude direction so that the ratio of the actual length in the longitude direction is 1: 1,
Based on the ratio of the length in the latitude direction calculated by the length calculation means in the latitude direction, the length in the latitude direction of the drawing area in the map information acquired by the map information acquisition means is adjusted, and the map after adjustment Map information output means for outputting information;
A map display device characterized by comprising: The latitude direction length calculating means obtains latitude information with the vertical center position of the specified drawing target area as a predetermined position, calculates the actual length in the longitude direction based on the value of the latitude information, Calculate the ratio of the actual length in the latitude direction to the actual length in the longitude direction,
The map display device according to claim 1. The latitude direction length calculation means repeatedly updates the calculation of the ratio of the length in the latitude direction every time the latitude information changes by 1/8 degree.
The map display device according to claim 1 or 2, wherein First storage means for storing map information divided into rectangular ranges divided by a certain latitude width and longitude width is provided, and the map display device displays map information appropriately according to the actual distance. A map display method,
A first step of receiving current position information of the vehicle;
In the map display device, a second step of acquiring map information from the first storage means based on the current position information of the vehicle received in the first step;
In the map display device, the drawing target area in the map information acquired by the map information acquisition unit is specified based on the current position information of the vehicle received in the first step, and the predetermined position in the specified drawing target area is specified. Based on the latitude information and the longitude information, the ratio of the actual length in the latitude direction and the actual length in the longitude direction is calculated, and based on this ratio, the length in the latitude direction is calculated based on the length in the longitude direction. A third step of calculating the ratio of the length in the latitude direction so that the ratio of the actual length to the actual length in the longitude direction is 1: 1;
Based on the ratio of the length in the latitude direction calculated in the three steps, the length in the latitude direction of the drawing area in the map information acquired in the second step is adjusted, and the adjusted map information is displayed on the map display device. 4 steps to output from
A map display method characterized by including. The third step obtains latitude information with the vertical center position of the drawing target area specified in the third step as a predetermined position, and calculates the actual length in the longitude direction based on the value of the latitude information. Calculating the ratio of the actual length in the latitude direction and the actual length in the longitude direction;
The map display method according to claim 4, wherein: The third step repeatedly updates the calculation of the ratio of the length in the latitude direction every time the latitude information changes by 1/8 degree.
The map display method according to claim 4 or 5, wherein the map is displayed. In order to execute display of map information appropriately according to an actual distance, comprising first storage means for storing map information by dividing it into a rectangular range delimited by a certain latitude width and longitude width Computer
Means for receiving vehicle current position information;
Means for acquiring map information from the first storage means based on the received current position information of the vehicle;
The drawing target area in the map information acquired based on the received current position information of the vehicle is specified, and the actual length and longitude in the latitude direction are determined based on latitude information and longitude information at a predetermined position in the specified drawing target area. The ratio of the actual length in the direction is calculated, and based on this ratio, the ratio between the actual length in the latitude direction and the actual length in the longitude direction is 1: Means for calculating the ratio of lengths in the latitudinal direction to be 1,
Means for adjusting the length of the drawing area in the acquired map information in the latitude direction based on the calculated ratio of the length in the latitude direction, and outputting the adjusted map information;
A computer program that functions as a computer program. The computer,
The latitude information is obtained with the vertical center position of the specified drawing target area as a predetermined position, the actual length in the longitude direction is calculated based on the value of the latitude information, and the actual length in the latitude direction and the longitude Means for calculating the ratio of the actual length of directions,
The computer program according to claim 7, further functioning as: The computer,
Means for repeatedly updating the calculation of the ratio of the length in the latitude direction every time the latitude information changes by 1/8 degree;
The computer program according to claim 7 or 8, further causing the computer program to function.

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