JPH07103783A - Map display method of navigation system - Google Patents

Abstract

PURPOSE:To enable judgment to be made easily by setting the priority of each map element for each display scale and the upperlimit values of the number of rows of characters and the number of characters in advance and then reading and displaying the map element data of priority corresponding to the display scale, at the same time displaying the map element data until the number of rows of characters and the number of characters being displayed reach the upper-limit values. CONSTITUTION:A plurality of map elements such as an expressway, a toll road, and a railroad are stored by a storage means 9 for each attribute. The upper-limit value of the number of characters is set in advance considering the priority of each map element and the number of characters to be displayed corresponding to a display scale and then is stored at the means 9. A CPU 3 judges whether the number of characters being displayed by a display means 16 reached a preset upper-limit value or not when displaying characters based on the character data out of the map element data read from the means 9 and then stops displaying the characters when the upper-limit value is reached, thus displaying a map which can be judged easily without any overlapping in characters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a map display method of a navigation system for displaying a map on display means in the navigation system.

[0002]

2. Description of the Related Art Conventionally, a navigation system is constructed as shown in FIG. 6, and in FIG.
Antenna 2 is a GPS receiver for receiving radio waves from GPS satellites via GPS antenna 1, and 3 is a GPS receiver 2
From a GPS receiver 2 via an interface (hereinafter referred to as I / F) 4 to derive the present position of the host vehicle. The CPU 5 detects the current position of the host vehicle via the I / F 6 according to the vehicle speed of the host vehicle. A vehicle speed sensor that outputs a signal to the CPU 3, 7
Is an operation means for outputting an operation signal corresponding to the operated key, such as a cursor movement key displayed on the display means described later, to the CPU via the I / F 8, and 9 is written map data for navigation for each section. A floppy disk controller (hereinafter, referred to as FDC) 10 is a storage unit including a floppy disk.

Further, in FIG. 6, 11 is a ROM storing a control program for the entire system, and 12 is a video RAM storing data to be displayed on a display means described later.
(Hereinafter referred to as VRAM), 13 is a work RAM for temporarily storing data, 14 is a display controller, and I / F
The display means 16 composed of an LCD or the like is controlled via 15,
A map for navigation based on the map data read from the storage means 9 is displayed on the display means 16.

At this time, the CPU 3, each I / F 4, 6,
8, 15, FDC 10, ROM 11, VRAM 12, work RAM 13, and display controller 14 as a navigation computer (hereinafter referred to as navigation E
18).

By the way, in this type of navigation system, a map is displayed at a display scale set by operating the operating means 7. For example, as shown in Table 1, a highway, a toll road, and a national road. , Map elements such as the names of municipalities and main intersections, and 1 / 10,000, 120,000, 1/4
The relationship with the presence / absence of display at a display scale of 1 / 80,000 or the like is set in advance, and each map element is displayed based on this relationship. However, the ◯ mark in Table 1 means that it is preferentially displayed.

[0006]

[Table 1]

That is, as shown in Table 1, at the display scale of 1 / 80,000, high-priority items such as highways, toll roads, national roads, and municipalities are displayed. The roads with the next highest priority such as major local roads and intersections are also displayed.

[0008]

However, as described above, the display priority of each map element is set in advance according to the display scale, and the map elements to be displayed at the actually set display scale are limited. However, when comparing the metropolitan area and the suburbs, even if the map is displayed at the same scale, in the metropolitan area, for example, the number of intersections and place names that should be displayed is larger than in the suburbs, so the letters overlap The map will be very illegible as it is displayed.

Therefore, the present invention has been made to solve the above problems, and an object thereof is to enable display of a map which is easy to read.

[0010]

According to a map display method of a navigation system according to the present invention, map data for navigation for each division is stored in advance in a storage means,
In a map display method of a navigation system, the control means reads out the map data of a necessary section from the storage means, and displays a map based on the read map data on the display means at a display scale set by operating the operation means. , As the map data, data of each map element such as a highway, toll road, railway, river, intersection name, place name, road data such as highway, toll road, national road, major local road, railway, water system, etc. Background data, intersection name,
It should be stored in advance in the storage means for each attribute such as place name and other character data, and the display priority for each of the map elements should be preset for each display scale, and should be displayed on the display means according to the display scale. The number of character strings or the upper limit of the number of characters is set in advance, the data of the map element having the priority corresponding to the set display scale is read from the storage means, and the map based on this data is displayed on the display means. At the same time, when displaying the characters based on the character data among the read map element data, the characters based on the character data are displayed until the number of displayed character strings or the number of characters reaches the upper limit value. There is.

[0011]

In the present invention, the number of character strings to be displayed or the upper limit value of the number of characters to be displayed is preset according to the set display scale, and when the display scale is set by the operation of the operating means, the display scale is supported. The data of the map element with the priority to be read is read from the storage means, the map based on this data is displayed, and the character data is displayed in the descending order of priority until the number of character strings actually displayed or the number of characters reaches the upper limit. Since the characters are displayed based on the displayed characters, it is possible to prevent the characters from being displayed in an overlapping manner, which makes the map easy to read.

[0012]

1 to 3 are flowcharts for explaining the operation of an embodiment of the present invention, and FIGS. 4 and 5 are operation explanatory views.

Since the navigation system to which this embodiment is applied has the same configuration as that shown in FIG. 6, the following description also refers to FIG. 6, but the following points are different from the above description.

That is, FIG. 4 shows data of a plurality of map elements such as highways, toll roads, railways, water systems such as rivers, intersection names, place names, etc. as map data to be stored in the storage means 9 in advance. As such, road data for highways, toll roads, national roads, major local roads, etc., background data for green spaces, railways, water systems, etc., character data for intersection names, water system names, place names, etc.
It is stored for each attribute such as symbol data of public facilities, interchanges, stations, etc. In particular, character data is stored in a format as shown in FIG.

At this time, in FIG. 5, data codes are codes indicating map elements such as intersection names and water system names, character positions are coordinates (x, y) on the map division, display parameters are half-width, reverse display, color, It is a specified content such as the number of characters, and by these, for example, data about a character string that is one specific name included in the map element "intersection name" is configured, and the data of one or a plurality of character strings is one character data format. Included in.

Further, each map element shown in FIG.
Similar to the case shown in, the display priority with respect to the display scale is preset, and this priority is stored in, for example, the storage unit 9.

Further, in consideration of the number and size of characters to be displayed, the upper limit of the number of character strings to be displayed according to the display scale is set so that the characters displayed on the display means 16 do not overlap. The upper limit value is determined and stored in advance in the storage means 9, for example.

Then, the CPU 3 presets the number of character strings of the character data actually displayed on the display means 16 when displaying the characters based on the character data among the map element data read from the storage means 9. It has a function of determining whether or not the upper limit value has been reached, and stopping the display of characters if the upper limit value has been reached.

Next, a series of operations will be described.

First, the overall operation will be described with reference to FIG.

As shown in FIG. 2, after initial settings are made (step S1) and the current position of the vehicle is calculated based on the received signal from the GPS receiver 2 (step S2), so-called auto-scroll determination processing is performed. Done (step S
3) It is determined whether or not the map being displayed needs to be rewritten (step S4).

Then, the determination result of step S4 is YES.
If so, the necessary map data file is derived (step S5), the map data of the derived file is read (step S6), and a map based on the read map data is displayed on the display means 16 (step S7). ), After the display position of the predetermined mark indicating the current position on the displayed map is updated (step S8), the process returns to step S2.

On the other hand, if the decision result in the step S4 is NO, the scale change key and the manual scroll key among the operation keys are read (step S9), and it is again decided whether or not the map needs to be rewritten. (Step S1
0), if the determination result is YES, the process proceeds to step S5, and if the determination result is NO, the process proceeds to step S8.

The map display process based on the map data will be briefly described. As shown in FIG. 3, after the screen is cleared (step T1), the road based on the line segment data in the read map data is displayed. And the like are displayed (step T2), the background and the like are displayed based on the painting data (step T3), and the characters indicating the place name and the like are displayed based on the character data (step T2).
4) In this way, the map display process ends.

Next, the above character display processing will be described with reference to FIG.

First, the upper limit of the number of character strings corresponding to the set display scale, that is, the maximum number Nmax of displayed character strings is determined (step U1), and the code assigned to each map element is read out ( In step U2), it is judged from the display priorities set for these map elements whether or not the map elements should be displayed at the set current display scale (step U3).

Then, the determination result of step U3 is YES.
If so, the data of one character string is read (step U4), it is determined whether or not this character string is included in the display screen (step U5), and the determination result is YES.
If so, the data of this character string is the work R for temporary storage.
Each attribute is stored in the AM 13 (step U6), and then the process returns to step U3. On the other hand, if the determination result in step U5 is NO, it is determined whether or not the check has been completed for all data of the corresponding priority ( Step U7), if the determination result is NO, return to Step U3,
If the determination result is YES, the process proceeds to the next step U8.

Next, in step U8, it is judged whether or not the check has been completed for all the character data of the set display scale (step U8). If the judgment result is NO, the process returns to step U2. If the determination result is YES, the counter built into the CPU 3 is set to 0 (step U9), and the work RA is displayed in the order of display priority.
Data for one character string is read from M13 (step U10).

Thereafter, one character string which is a concrete name such as a highway name or a place name is displayed based on the character string data read in step U10 (step U11), and the count value of the counter is incremented. (Step U12) It is determined whether or not all the data temporarily stored in the work RAM 13 is displayed (step U13). If the determination result is YES, it is determined that there is no character string to be displayed, and the operation is continued. When the determination result is NO and the determination result is NO, it is determined whether the count value of the counter has reached the initially set maximum number of character strings Nmax (step U).
14) If the determination result is NO, the process returns to step U10, and if the determination result is YES, it is determined that the display should be stopped because it is difficult to read the map if the character string is displayed any more. The operation ends.

Therefore, the upper limit value of the number of character strings based on the character data to be displayed is determined in advance in accordance with the set display scale, and the number of character strings actually displayed reaches the upper limit value in descending order of priority. Since the characters based on the character data are displayed, it is possible to prevent the characters from being displayed overlapping each other.
It is possible to display a map that is very easy to read.

In the above embodiment, the case where the upper limit of the number of character strings is set has been described, but it goes without saying that the upper limit of the number of characters may be set.

[0032]

As described above, according to the map display method of the navigation system of the present invention, until the number of character strings or the number of characters actually displayed on the display means reaches the upper limit value determined in advance according to the display scale. Since the characters based on the character data are displayed in descending order of priority, it is possible to display a map that is very easy to read without the inconvenience of overlapping characters as in the conventional case, and is suitable for a navigation system.

[Brief description of drawings]

FIG. 1 is a flowchart for explaining the operation of an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of one embodiment.

FIG. 3 is a flowchart for explaining the operation of one embodiment.

FIG. 4 is a diagram illustrating the operation of the embodiment.

FIG. 5 is an operation explanatory diagram of the embodiment.

FIG. 6 is a block diagram of a general navigation system.

[Explanation of symbols]

 9 storage means 16 display means 18 navigation ECU

Claims (1)

[Claims] 1. A map data for navigation for each division is stored in advance in a storage means, and the map data of a necessary division is read from the storage means by the control means,
In a map display method of a navigation system for displaying a map based on the read map data on a display unit at a display scale set by operating an operating unit, the map data includes a highway, a toll road, a railroad, a river, an intersection. Data of each map element such as name, place name, etc. can be used as road data for expressways, toll roads, national roads, major local roads, etc.
It is stored in advance in the storage means for each attribute such as background data of railways, water systems, etc., character data such as intersection names, place names, etc., and the display priority for each map element is preset for each display scale and displayed. The number of character strings to be displayed on the display means or the upper limit of the number of characters is set in advance according to the scale, and the map element data of the priority corresponding to the set display scale is read out from the storage means. When displaying the map based on the data on the display means and displaying the characters based on the character data among the data of the read map elements, the characters are displayed until the displayed number of character strings or the number of characters reaches the upper limit value. A map display method for a navigation system, which displays characters based on data.