JP2001142819A - Method and device for plotting map - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of knowing the position (area), where map data to be transmitted belong, on a map while utilizing the standard file form of GIF or JPEG for a routing system as it is and to display the map on a screen in the right positional relation on the basis of that positional information. SOLUTION: In the map distribution for distributing required map data by communications, the map data are distributed after adding a name, from which the position on the map can be calculated, as a file name thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a system for distributing map data using a communication system such as the Internet.

[0002]

2. Description of the Related Art When implementing a pedestrian navigation system or a car navigation system on a mobile terminal,
Due to the small size and light weight, there are many cases where the storage area is considerably limited. Therefore, in order to download and use only the necessary map area, the map data is divided into a mesh structure. In addition, when considering a route search in a small memory capacity of a mobile or the like, it is desirable that the data is as small as possible, and the map data is usually in a compressed data format.

[0003] Various file formats are used as compressed data formats. The most widely used still image files on the Internet include the GIF format and the JPEG format. These file formats can be handled by standard browsers. It is widely used as a global standard because image data can be handled by standard commercial browsers without requiring the user to develop special software.
FIG. 1 shows a GIF file structure. Although this diagram is shown as a minimum unit of a block, a plurality of blocks can be included. Although two types, Structure 1 and Structure 2, are mounted, the way of holding the color table is slightly different, and both are the same. Hereinafter, the structure of the figure will be briefly described.

[0004] A logical screen is a logical screen representing the entire area displayed in a GIF file.
In most cases, the size of the logical screen is the image size in the F file. Of course, the logical screen can contain a plurality of logical screen images smaller than the logical screen. This logical screen is defined by a logical screen descriptor and a global color table. The logical descriptor defines the width and height of the image, the color index of the background color (palette number in the case of Windows), the aspect ratio of pixels, and the like, and the color table defines information about colors. The colors available in the GIF range from two colors to a maximum of 256 colors.

[0005] The image descriptor is a block which is always required before the image data. The image position, size, area relating to the local color table, information relating to the local color table, and the storage format of the image data (interlace,
Non-interlaced). The image data is digital data captured by an image scanner or the like, and is compressed by a certain algorithm called “Variable-Length-Code LZW Compress”. The LZW method can compress image data at high speed and at a relatively high compression rate.
It can store image data efficiently and is suitable for high-speed communication.

[0006] The JPEG format is also a method of recording image data widely used on Internet homepages. JPEG can be handled not only by various Web browsers and many kinds of image creation software, but also by the difference of OS such as Windows, Mac, UNIX, CP such as Intel, Motorola, Sun, HP, etc.
It has the advantage that it can be used without worrying about the difference between U manufacturers. Another feature is that the compression ratio is much better than other file formats. However, if the compression ratio is too high, there is a disadvantage that the image quality deteriorates. JPEG is suitable for performing data communication on the Internet because it is established for transmitting still image data over a digital communication network.

[0007]

In the above search system, when map data is transmitted as a file, in addition to bitmap data representing a map, the map data is stored in any area on the entire map. It is necessary to have character data of latitude and longitude indicating whether the data belongs to
In a general image data file format, text data and image data are in different formats.When using a general-purpose file format, text data representing a position and image data representing a map are transmitted separately. The method of combining and displaying the map and location in the receiving application, or the method of creating a header file in a user-specific format without using a general-purpose file format and transmitting and receiving with a unique application Must be used.

GIFs and JPGs can be easily handled by JAVA as applications on the Internet. To receive a still image on the Internet and display the received image on a browser using a Java applet, use the Java AP
Specify a GIF or JPEG image file with Applet.getImage, which is I, and draw with Graphics.drawImage. Therefore, special image operations (such as decompression of compressed data and conversion to image data) using programs developed by the user.
Since it is not necessary to carry out, the development work and cost of the application program are reduced.

[0009] JAVA can be used as a standard in Microsoft Internet Explorer and Netscape Netscape. In addition, JAVA will be able to be used on mobile terminals in order to create a mechanism for dynamically downloading contents such as maps, and prototypes for mobile phones and mobile terminals have been announced.

[0010] Images other than GIF and JPG cannot be displayed in JAVA. If you use ActiveX, you can display in your own file format, but you have to develop your own image display program, which not only increases the development load, but also makes it impossible to use with browsers other than Microsoft Internet Explorer. The patent of this case can be similarly applied to any development environment that can easily display a standardized image file using a function even if it is not necessarily JAVA.

The problem to be solved by the present invention is that in a route search system, a standard file format such as GIF or JPEG is used as it is, and to which position (area) on the map the transmitted map data belongs. It is to propose a method to understand and to display a map on a screen in a correct positional relationship based on the positional information.

[0012]

According to a first aspect of the present invention, there is provided a map distribution system for distributing required map data by communication, in a map distribution, wherein a file name of the map data is used. It is distributed with a name that can be calculated on the map.

According to the second and fifth aspects of the present invention, when a required map data is distributed by communication and a map is displayed on a screen, a position on the map can be calculated as a file name of the map data. Distribute with a name.

According to the third and sixth aspects of the present invention, in a route search using map data for position designation, when the required map data is distributed by computer communication, the file name of the map data is displayed on the map. It is distributed with a name that can be calculated. As the file name indicating the position on the map, the latitude and longitude at the upper left and lower right of the mesh area are appropriate, but various other methods can be used.

In distributing map data to a portable map image display device, when necessary map data is called, a position on the map is calculated from a position on the display screen of the map data of the area selected by the instruction key. Then, a map data file having a file name corresponding to the position on the map is called.

In the route search system, a route from a departure point to a destination is expressed as a transportation network using points as nodes and links between points as links, and a travel time or a travel distance is calculated as a cost by a label determination method using a computer. Is used to search under the shortest cost condition.

The route search system requires map data for specifying a destination and the like in addition to the traffic network data used in the route search. Currently, portable search route devices such as car navigation systems use map information on CD-ROs.
M on a large-capacity recording medium such as
, And based on the location information, the CD-
The map information registered in the ROM is read into the memory and displayed. However, the CD-ROM stores the latest information at a certain point in time, and the map information becomes older as time passes. Therefore, in order to always obtain the latest map information, it is necessary to obtain the latest map information by some method. The most influential means is distribution of map data via the Internet or the like.

In the case of a portable device, a large-capacity storage medium may not be provided in some cases, and it is useful to take in map information as necessary using communication means such as the Internet. In that case, the map is divided into appropriate regions. In order to receive a map divided at appropriate boundaries and reproduce the map in a correct positional relationship, it is only necessary to know to which region (latitude and longitude and range) on the entire map the received map belongs. Therefore, in the present invention, in order to solve the above problems, GIF and JPEG
In order to be able to use image files in standard formats such as, the file name of the map file to be sent is given a name indicating the position on the map (latitude and longitude and range), and the position can be calculated by the file name I do.

Specifically, as the file names, <a numerical value capable of calculating the latitude of the lower left of the map>, <a numerical value capable of calculating the longitude of the lower left of the map>, <a numerical value capable of calculating the latitude of the upper right of the map>, < The numerical value at which the latitude at the upper right of the map can be calculated> is a coded file name. File format is GIF or JPE
Since it is an international standard file format such as G, the map data can be sent as it is, and the browser on the receiving side can handle the map data as it is.

When the map is actually displayed, the coded latitude and longitude included in the file name are converted into numerical values, and the map position is set to the latitude and longitude to display an image at a correct position. Since the map data is in a data format that can be handled by the browser, even if a plurality of map data are sent, the original accurate map can be restored and displayed by specifying only the correct positional relationship.

[0021]

Embodiments of the present invention will be described. In the following, an example of calculating an area from a mesh code specified by JIS will be described. A method of knowing the position of a file name of a segmented map data to be transmitted and an application program on the receiving side which uses the file name and the position in the receiving program will be described. As shown in FIG. 2, the map is divided by an appropriate mesh, and each section is given a name. If the map data is sent with that name as the file name, the receiving side can know the latitude and longitude from the file name in the correspondence table. FIG. 3 is a table in which file names are associated with latitude and longitude, and is an example in which a common table is used on the transmission side and the reception side. In the example of FIG. 3, position data is associated with all file names.

In the case of a map divided into equal intervals, if only the latitude and longitude and the mesh interval of the position data of the first map (A11 in the figure) are stored in the receiving application, a numbered file is stored. Any position can be calculated by name. If the latter method is used, the table size can be reduced.

However, the drawback of the method for determining the position on the map using the above-mentioned table is that a table for associating a file with a position must be stored in the application on the transmitting side and the application on the receiving side. Each time there is a change, the table must be changed.

To solve this drawback, it is sufficient if the latitude and longitude at the lower left and upper right corners of the map can be calculated directly from the file names.
In the present invention, file names are assigned to map regions so that the lower left and upper right positions of the map can be calculated. Specifically, the following example will be described.

In JIS, a secondary mesh code and a tertiary mesh code are defined as a map mesh dividing method. Since the secondary mesh code is given according to the following rule, the coordinates of the lower left and the upper right of the map can be easily calculated from the code number. That is, the secondary mesh code is i
When jkl (i and j are two digits and k and l are one digit), the coordinates of the end can be obtained by the following formula. Lower left north latitude Nd = i / 1.5 + (1 / 1.5 / 8) × k Lower left east latitude Ed = (j + 100) + (1/8) × 1 Upper right north latitude Nu = i / 1.5 + (1 / 1.5 / 8) ) × (k + 1) Lower right east latitude Eu = (j + 100) + (1/8) × (l + 1)

For example, the secondary mesh code ijkl is
When 533945, Nd = 53 / 1.5 + (1 / 1.5 / 8) * 4 = 35.67 Ed = (39 + 100) + (1/8) * 5 = 139.25 Nu = 53 / 1.5 + (1 / 1.5 / 8) * (4 + 1) = 35.75 Eu = (39 + 100) + (1/8) * (5 + 1) = 139.75

In consideration of the above points, a method of giving a secondary mesh code conforming to the JIS standard as a file name will be described below.

The secondary mesh code is a combination of numbers indicating a primary area division and a secondary area division determined in the following order. Specifically, the following procedure is followed. (1) The number indicating the first zone section is a two-digit number i indicating the frequency obtained by multiplying the southern latitude of the section by 1.5, and a two-digit number j obtained by subtracting 100 from the number indicating the west latitude. Is a four-digit number ij that is combined in this order. Example: For latitude 36 degrees north and 142 degrees east longitude, i = 36 * 1.5 = 54 and j =
Since 142-100 = 42, the result is 5442. (2) The numbers indicating the second area division are as follows: For each division obtained by dividing the primary area division into eight parallel and meridian directions, the latitude direction is from south to north, and the meridian direction is west. From the east to the east, numbers from 0 to 7 are assigned, respectively, and a two-digit number kl is obtained by combining the numbers in the latitudinal direction and the numbers in the meridian direction in this order. Example: If the value is 3 in the latitude direction and 5 in the meridian direction, the result is 35. (3) The name given to the map data file to be sent is Fijkl.m
mm. Here, F is an appropriate character string, i, j, k, l
Is a number obtained by the above calculation, and mmm is an extension (.jpg, .gif, etc.) defined in the image file format.

Next, a method of calculating the latitude and longitude of a point designated on a map will be described. The transmitted map is a rectangular area, and the coordinates of the lower left and upper right ends of the rectangle are known,
If the number of dots in the vertical and horizontal directions of the map is known, the latitude and longitude of the position specified on the map on the drawing can be obtained by calculation. A specific example will be described below by way of example. Note that the vertical Y dots and horizontal X dots of the map displayed on the screen shown in the following example are described in the header (see FIG. 1) of a GIF format or JPEG format file.

When searching for a route on a map, the latitude and longitude of a position specified by a pointing device such as a mouse must be calculated. For example, as shown in FIG. 4, when a map is transmitted in a unit of a secondary mesh of vertical Y horizontal X dots, if the position specified on the map is (x, y), it corresponds to (x, y) coordinates. The latitude and longitude are as follows. Latitude = Lower left latitude Nd + 1 / 1.5 / 8 * (y / Y) Longitude = Lower left longitude Ed + 1/8 * (x / X) Because the latitude width of one secondary mesh is 1/1. Is 1/8.

As described above, if a mesh code or a character string capable of finding an area on a map is used instead of a mesh code as a descriptor of a map data file, a terminal side can easily be prepared without preparing a special header file. The position of the map can be specified, and the latitude and longitude of an arbitrary point generally used in the route search system can be calculated from the position specified on the screen.

[0032]

[Embodiment] An example is shown in which the present position received by GPS is displayed on a map, a destination is specified on the map, and route search guidance is performed. It is assumed that the map is divided into secondary mesh units, and one mesh is composed of horizontal X dots and vertical Y dots. It is assumed that the current position is latitude lat and longitude log by GPS. The unit is seconds. One degree is 3600 seconds, and the secondary mesh has a latitude of 300 seconds and a longitude of 450 seconds. (X, y) is obtained by the following formula. % Is an operator for calculating the remainder. x = (log% 450) * X / 450 y = (lat% 300) * Y / 300 If the current position mark is displayed on (x, y), the current position can be confirmed on the map field.

For example, when the position is received by GPS every two seconds, when it moves, it may be out of the displayed mesh. In such a case, every time the GPS is received, the mesh number including the latitude and longitude is calculated. If the mesh number is the same as the previous time, the same map is displayed as it is. If the mesh number is different, the map is transmitted. Just do it.

In this way, it is possible to plot the current position on a map viewer that is switched on a mesh basis. Further, when searching for a route from the current point to a certain point, the destination must be specified by latitude and longitude. If it is desired to specify on the map, if the destination is in the same mesh, the latitude and longitude can be calculated from the coordinates pointed on the screen using the equation [0031]. However, if not in the same mesh, the mesh must be moved. For example, if there is a move button that can move in eight directions, up, down, left, right, and diagonally, if the currently displayed mesh is 533935 and the destination is on the upper right, the upper right is 533946 due to the regularity of the mesh number. You can send the file F533946.GIF from the server. If the destination is specified in the transmitted mesh and the latitude and longitude are calculated from the screen coordinates by the method described above, the latitude and longitude of the departure point (current location) and the destination are aligned, so that a route search can be performed. .

Further, as shown in FIG. 5, it is possible to always display the current position in the center. With JAVA, an image file in mesh units can be displayed at the specified position on the screen. Therefore, an adjacent mesh including the current location is downloaded to the terminal, and the viewport is cut off and displayed as shown by the dotted line in FIG. be able to.

In the illustrated example, the sections 35, 36, 45, 46
Becomes File names of these four maps are F533935.gif, F533936.gif, F533945.gif, F
If you send it with 533946.gif, the receiving terminal will arrange them in memory, specify the range to be displayed, and display it on the terminal screen.

In order to receive a still image on the Internet and display the received image on a browser, it is only necessary to write <IMGSRC = "file name of image"> in the HTLM document. Therefore, it is not necessary for the user to perform a special image operation (decompression of compressed data, conversion to image data, etc.) with a program originally developed by the user, thereby reducing the development work and cost of application programs.

[0038]

According to the present invention, area (latitude / longitude and range) information necessary for displaying a map is inserted into a file name, and is decoded on the receiving side based on the file name to determine which area of the received map data is on the map. Is calculated so that it can be used for route search.

Therefore, it is not necessary to add the latitude and longitude information by attaching a special header file, the conventional international standard file format can be used as it is, and the communication and use of the map information is possible as a versatile form. GIF
The 89a specification adds a block for storing comment data, text data, and application-specific data in addition to image data. However, it is not necessary to use such a specification, and the required information can be obtained only by the file name. In addition, the present invention is versatile because it can be handled by a standard browser without being affected by the specification of the file format.

In the present invention, since the area on the map can be calculated from the file name, there is no need to develop a user-specific application for transmitting and receiving and displaying the image data file. The still image file format can be used as it is, and data compression, decompression, and image display by a browser can be handled by standard software that has been distributed so far. Therefore, there is no need to create a special header file or develop a special application for handling the file, which is economically advantageous.

In the embodiment of the present invention, a method for extracting an area on a map from a table corresponding to a file name,
The method of calculating the area directly from the file name was shown. In the former case, a table or parameters corresponding to the table must be prepared in advance, but in the latter case, the position on the map can be determined directly from the file name. For this reason, the latter is more versatile. In the latter case, in particular, if the map mesh division method of the JIS standard is used, the area can be calculated directly from the file name, and can be standardized as a general-purpose positioning method.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a GIF format file structure according to the related art.

FIG. 2 is a diagram illustrating map divisions and identifiers for describing a method for obtaining a table by assigning file names to the divided maps in an array according to the embodiment of the present invention and obtaining an area on the map.

FIG. 3 is a diagram showing a table for associating a file name with a latitude and longitude according to the embodiment of the present invention.

FIG. 4 is a diagram for explaining an example of calculating an actual latitude and longitude on a map from (x, y) coordinates pointed on a map on a screen in the embodiment of the present invention.

FIG. 5 is a diagram for explaining a method of receiving a plurality of map data along a search route and displaying the map data on a terminal screen in the embodiment of the present invention.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) G09B 29/00 G06F 15/40 370C 5H180 15/62 335 9A001 F term (Reference) 2C032 HB03 HB22 HB25 HB31 HC11 HC32 HD16 2F029 AB07 AB13 AC02 AC08 AC14 5B050 BA17 CA07 FA02 FA19 GA08 5B075 ND06 PQ02 PQ05 UU13 UU16 5B089 JA33 JB03 JB22 JB24 KA10 KE02 5H180 FF05 FF22 FF32 9A001 EE04 HZ23 JJ11 JJ13 JJ11 JJ13 JJ11 JJ13 JJ12

Claims (6)

[Claims] 1. A map distribution system for distributing required map data by communication, wherein the map data is distributed with a file name of the map data capable of calculating a position on the map. 2. A map display system for distributing required map data by communication, wherein the map data is distributed with a file name of the map data capable of calculating a position on a map. 3. In a route search system using map data for position designation, when distributing necessary map data by computer communication, a file name of the map data is given a name capable of calculating a position on the map. A route search method system characterized by delivering. 4. A map distribution method for distributing required map data by communication, wherein the map data is distributed with a file name of the map data capable of calculating a position on the map. 5. A map display method for distributing required map data by communication, wherein the map data is distributed with a file name of the map data capable of calculating a position on the map. 6. In a route search using map data for position designation, when delivering necessary map data by computer communication, a file name of the map data is given with a name capable of calculating a position on the map. A route search method characterized by: