JP2003187256A - Data structure of graphic data to be recorded in electronic map data and electronic map display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce capacity of electronic map data. <P>SOLUTION: When a polygon to constitute an electronic map is plotted, there is hardware in which an upper limit exists in the number of plottable apexes. In order to plot the polygon having apexes exceeding the upper limit number in such hardware, divided segment data to be 'cut lines' for dividing one polygon into a plurality of polygons is defined. Thus, data capacity can be reduced since a plurality o pieces of polygon data are not necessary to be prepared. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a data structure of graphic data recorded in electronic map data and an electronic map display device.

[0002]

2. Description of the Related Art Conventionally, electronic map data used in personal computers and car navigation systems are
It was recorded on a recording medium such as a CD-ROM. A CD-ROM drive or the like is physically connected to these devices, and map data can be read at high speed. For example, in the case of a CD-ROM drive, several megabytes /
In the case of a DVD drive device, the transfer speed is as high as a dozen or more megabytes / second.

Further, in recent years, a technique for transmitting and receiving electronic map data via the Internet is also being used. By storing the electronic map data in a server on the Internet, it is not necessary to individually distribute the recording medium to the client, so that the cost can be reduced.
This is also because there is an advantage that the version upgrade of the electronic map data can be centrally managed.

[0004]

However, the transfer rate of the Internet is, for example, about 1.2 kilobytes / second, which is generally used in a mobile phone, and 8 to 16 kilobytes even in ISDN communication. / Sec. Therefore, even if the electronic map data that has been conventionally recorded in a recording medium is used as it is on the Internet, there is a problem that a large amount of time is spent from reading the map to displaying it due to the difference in the transfer speed. It was

The present invention has been made in view of the above problems, and an object thereof is to reduce the capacity of electronic map data.

[0006]

Means for Solving the Problem and Its Action / Effect To solve the above problems, the present invention has a first configuration,
The following configuration was adopted. That is, the data structure of the graphic data recorded in the electronic map data is at least 1
By polygonal vertex data in which one interior angle has an angle of 180 degrees or more, and a line segment having the apex having the interior angle of 180 degrees or more and other arbitrary vertices in the vertex data as ends,
It is a data structure in which the polygon is recorded in association with division line segment data that divides the polygon into a plurality of polygons with all interior angles less than 180 degrees.

The graphic recorded in this data structure is a polygon in which at least one interior angle is 180 degrees or more. The dividing line segment data is a line segment for dividing this polygon into polygons whose interior angles are all less than 180 degrees. The significance of such division will be described below step by step.

In a display device such as a personal computer, a car navigation system, or a mobile phone, there is a limit on the number of vertices of a drawable polygon due to hardware restrictions. Of the shapes displayed on the map,
For example, a river is defined by a polygon with a very large number of points, but if such a constraint exists, it must be represented by a set of polygons composed of vertices that do not exceed the upper limit number mentioned above. . Therefore, in this case, the number of polygons becomes enormous. Further, since the upper limit number differs depending on the hardware, it becomes necessary to prepare a plurality of types of map data according to the hardware that displays the map.

As one method for avoiding such an adverse effect, when displaying a polygon having a number of vertices exceeding the upper limit, the display device side of the map divides the polygon into displayable polygons by an arbitrary diagonal line. It is possible to adopt a method of displaying it.

FIG. 18 is an explanatory view showing a polygonal divided display. Here, a case where a heptagon defined by the vertices p1 to p7 is displayed will be described. It should be noted that the display device for displaying this graphic is supposed to be able to display only a pentagon or less, due to restrictions on hardware. For example, when the display device is divided into polygons a1 to a3 by diagonal lines L1 and L2 in the figure, this heptagon is properly displayed. On the other hand, when the line is divided by the diagonal lines L3 and L1, the portion that should not be filled (hatched portion in the drawing) is filled, and this heptagon becomes an inappropriate display. This is a vertex p5 with an interior angle of 18
This is due to the fact that it is above 0 degree. With respect to all polygons whose interior angles are less than 180 degrees, even if they are divided by any diagonal line, the original polygon is not overflowed and filled.

In the present invention, from this viewpoint, the shape on the map is defined by a set of polygons (hereinafter referred to as convex polygons) whose interior angles are all less than 180 degrees. For this reason, it is necessary to divide a polygon including an interior angle of 180 degrees or more into a convex polygon. For example, in the example of FIG. 18, the original angles of the vertices p3 and p5 of the original heptagon are 180 degrees or more, but by dividing by the diagonal lines L1 and L2, it is possible to divide into three convex polygons a1 to a3. .

Here, it is possible to define the three convex polygons a1 to a3 as individual polygons. However, in this case, header information is individually required for each of the polygons a1 to a3, and the vertices p3, p
The data representing 5 and p7 will be recorded in duplicate in two or more polygons. Therefore, the three convex polygons a1
If a to a3 are individually defined as polygons, the amount of data will increase.

On the other hand, according to the present invention, the dividing line segment L for generating the convex polygons a1 to a3 is applied to the original heptagon.
1 and L2 are defined. The dividing line segment is a line segment for dividing a polygon, and is specified by vertices serving as a start point and an end point. By doing so, it is possible to substantially define a polygon as an aggregate of convex polygons while suppressing an increase in the amount of data.

As described above, the division of a graphic according to the present invention has an effect of avoiding a hardware limitation on the maximum number of vertices of a drawable polygon while suppressing an increase in the amount of data. it can. If the convex polygon defined in the present invention can be further divided and displayed on the display device side into a polygon having a smaller number of vertices than the upper limit number of vertices, the number of vertices of the convex polygon is not necessarily the upper limit number of vertices. It does not have to be less than.

In order to display the graphic recorded in the electronic map data according to the above data structure, the following configuration is adopted as the second configuration of the present invention. That is, an electronic map display device for displaying an electronic map, which refers to electronic map data in which the data structure of the first configuration is recorded, and inputs the vertex data and the dividing line segment data. And a drawing unit that draws a polygon using the vertex data, the drawing unit divides the polygon into a plurality of polygons by the dividing line segment data, and draws each polygon. It is an electronic map display device for performing.

The map data reference unit refers to the electronic map data in which the data structure of the above-mentioned first structure is recorded, and inputs the vertex data and the dividing line segment data. The drawing unit draws a polygon based on the vertex data and the dividing line segment data. With such an electronic map display device, it becomes possible to draw a polygon based on the above data structure. This map display device may further display the polygon divided by the dividing line segment into polygons having less than the above-described upper limit number of vertices.

Next, the following configuration is adopted as the third configuration of the present invention. That is, in the data structure of the graphic data recorded in the electronic map data, the coordinate data for each point sequence forming a broken line consisting of continuous line segments, and the display control data for designating the display or non-display of the line segments. When,
Is a data structure that is recorded in association with each other.

With such a data structure, a polygonal line including a line segment in the display state and a line segment in the non-display state can be expressed. That is, it becomes possible to represent a plurality of polygonal line figures displayed at distant places with one data. Since header information recording various information is usually added to the graphic data, the data capacity for the header information can be reduced by collecting a plurality of graphics into one data.

In the above data structure, when the continuous line segments are drawn in order in the display control data,
It is preferable to use data that specifies the point where the display mode is switched from display to non-display or from non-display to display because the display / non-display can be controlled by a simple method.

In order to display the graphic recorded in the electronic map data according to the above data structure, the following constitution is adopted as the fourth constitution of the present invention. That is, it is an electronic map display device for displaying an electronic map, and refers to electronic map data in which the data structure of the third configuration of the present invention is recorded, and refers to map data for inputting the coordinate data and the display control data. An electronic map display device comprising: a unit; and a drawing unit that switches display / non-display based on the display control data and draws a polygonal line according to the coordinate data.

With such an electronic map display device, it becomes possible to draw a plurality of line segments displayed at distant places based on the polygonal line figure recorded according to the above data structure.

Next, the following constitution was adopted as the fifth constitution of the present invention. That is, a data structure of symbol data or display character data recorded in electronic map data having map data that can be scaled up and down in multiple stages,
Display content data that specifies the shape or character string of the symbol to be displayed, coordinate data that specifies the position where the symbol or character string is to be displayed, and the upper limit or lower limit of the step of displaying the symbol or character string. It is a data structure in which display stage data designating a value is recorded in association with each other.

For example, in map data that can be scaled up / down in 5 steps, a 5-bit flag is required to control the display / non-display of characters and symbols on the map according to the step. However, if the above data structure is used, the upper limit value or the lower limit value of the display stage may be designated. That is, when "5" is represented by a binary number, it becomes "101", so that if there is at least 3-bit data, display / non-display according to the stage can be controlled. Therefore, in this case, the data capacity of 2 bits can be reduced. The symbol may be, for example, a map symbol representing a school, post office, fire department, or the like. Further, the character may be its name or the like. Since there are an infinite number of such symbols or characters in the map, if the data capacity of 2 bits can be reduced by one character / symbol data as described above, the reduction of the data of a large amount as a whole can be achieved. It is possible to plan.

Next, as a sixth configuration of the present invention, the following configuration is adopted, that is, an electronic map display device for displaying an electronic map, in which the data structure of the fifth configuration of the present invention is recorded. Referring to electronic map data, a map data reference unit for inputting the display content data, the coordinate data, and the display stage data, a stage designating unit for designating a scaling stage of a map to be displayed, and An electronic map display device comprising: a drawing unit that draws the symbol or the character string based on the display content data and the coordinate data when the designation satisfies the condition specified by the display stage data.

With such an electronic map display device, when displaying a map, it is possible to draw a symbol or character by designating an upper limit value or a lower limit value of the display stage of the map.

Further, the following configuration is adopted as the seventh configuration of the present invention. That is, the data structure of the object group recorded in the electronic map data is provided with an object area for holding a plurality of objects in a continuous address space, and the object area is divided into a plurality of object groups at the delimiters of the objects. The data structure is divided and has an index area for holding index data designating the start address of the object group, separately from the object area.

According to this data structure, one index data is assigned to the object group. Therefore, since it is not necessary to add index data to all objects, the data capacity of the index area can be reduced.

Next, the following constitution was adopted as the eighth constitution of the present invention. That is, an object search device for searching an arbitrary object recorded in electronic map data, comprising a reference unit for referring to the electronic map data in which the data structure of the seventh configuration of the present invention is recorded, and an object to be searched. A search target input unit for inputting an index for specifying the index data, an index data search unit for searching the index region for index data indicating the start address of the object group to which the search target belongs, and in the object region, The object search device includes a sequential search unit that sequentially searches the addresses recorded in the index data and searches for a search target.

With such an object retrieval device, a desired object can be retrieved from the objects recorded according to the above data structure. The start address of the object group to which the search target object belongs can be searched by the index data, and the search can be performed by sequentially incrementing the address from the start address to the address at which the target object is recorded. The object may be graphic data for displaying a road, a building, or the like, or may be route data recording a road connection state.

Further, as a ninth structure of the present invention, the following structure is adopted, that is, recorded in electronic map data,
A data structure of graphic data defined by a plurality of continuous point sequences, wherein absolute coordinate data for holding coordinates of a part of the point sequence by absolute coordinates, and coordinates for the rest of the point sequence are predetermined reference points. The relative coordinate data held by the relative coordinates from, the area in which the absolute coordinate data is recorded, and the area in which the relative coordinate data is recorded are recorded at the boundary, and the type of coordinate data of the next recorded area is specified. And a type designating data for which the relative coordinate data can be taken, and the range of the relative coordinate data is narrower than the range of the absolute coordinate data.

Conventionally, as a data structure of graphic data consisting of continuous broken lines, a data structure consisting of only absolute coordinates, only the first one point is represented by absolute coordinates, and the remaining points are represented by relative coordinates from the immediately preceding point. There was a data structure. However, in the former data structure, it was necessary to secure a sufficient data width so that any value can be recorded regardless of the size of the coordinate value. Therefore, there is a problem that the data capacity is increased as a whole. On the other hand, in the latter data structure, since it is sufficient to record the movement amount between the coordinates, the data width can be kept relatively small. However, when the movement amount is large, the movement amount can be limited by the limited data width. In order to express, there was a case where an originally unnecessary coordinate point had to be set as a relay point. In addition, the data capacity is suppressed by recording the absolute coordinate value or the relative coordinate by multiplying a constant coefficient such as ½ or ⅓, and the coordinate value is doubled or tripled when drawing a figure. There was also. However, in such a method, since the original resolution of the display device cannot be utilized, there is a problem that the accuracy of the map deteriorates.

According to the above data structure of the present invention, it is possible to define graphic data in which absolute coordinate data and relative coordinate data are mixed and recorded. That is, a plurality of areas in which absolute coordinate data is recorded and areas in which relative coordinate data are recorded can exist in one figure data. With such graphic data, if the amount of movement between coordinates is small, the coordinates are recorded using relative coordinates,
If the amount of movement is large, the coordinates can be recorded using absolute coordinates. Therefore, the data area can be used efficiently, and the increase in the data capacity can be suppressed while maintaining the accuracy as a whole. Between the area where the absolute coordinate data is recorded and the area where the relative coordinate data is recorded, there is type designation data for designating whether the coordinate data of the area to be recorded next is absolute coordinate data or relative coordinate data. Since the data is recorded, it is possible for the display device side to draw the figure by switching the coordinate systems of both by referring to the type designation data.

The relative coordinate reference point can be set variously. For example, any point represented by absolute coordinate data in the graphic data may be used as the reference point. Alternatively, the immediately preceding point in the point sequence may be used as the reference point. Further, virtual reference points not included in the graphic data may be provided. In this case, it is preferable that the type designation data include a parameter that designates the absolute coordinates of the virtual reference point.

In the above data structure, the type designation data may include a parameter designating a range that the relative coordinate data can take. For example, the range may be designated by the number of bits or the number of bytes. That is, when the absolute coordinate data is represented by 16 bits, the relative coordinate data can be designated as 8-bit if desired to be -127 to 127, and can be designated as 4 bit if desired to be -7 to 7. do it.

By doing so, the data capacity for recording the relative coordinate data can be flexibly designated according to the movement amount between the coordinates. Therefore, the data area can be used more efficiently. The X coordinate range and the Y coordinate range may be specified separately.

Next, as a tenth constitution of the present invention, the following constitution is adopted, that is, an electronic map display device for displaying an electronic map, in which the data structure of the ninth constitution of the present invention is recorded. A map data reference unit that refers to electronic map data and inputs the absolute coordinate data, the relative coordinate data, and the type designation data, and absolute coordinates that specify the position of a point to be drawn based on the absolute coordinate data. A specific part,
A relative coordinate specifying unit that specifies the position of a point to be drawn based on the relative coordinate data and the absolute coordinate of the reference point, and switches the absolute coordinate specifying unit and the relative coordinate specifying unit based on the type specifying data. An electronic map display device comprising: a drawing unit that draws the graphic.

According to such an electronic map display device, the drawing unit switches between the absolute coordinate specifying unit and the relative coordinate specifying unit to draw a figure. By doing so, it becomes possible to draw the figure recorded according to the above data structure.

The present invention can also be configured as a computer program for causing a computer to realize a function of displaying various figures, characters, and symbols on the electronic map display device. It can also be configured as a computer program that causes a computer to realize a function for causing the object search device to search for an object. The computer program and the electronic map data in which the above various data structures are recorded may be recorded in various recording media such as a flexible disk, a CD-ROM, a DVD, an IC card and a hard disk.

[0039]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below based on Examples in the following order. A. Map display system: B. Mobile phone functional block overview: C. Electronic map data summary: D. Polygon data: (D1) Polygon data structure: (D2) Polygon drawing processing: (D3) Convex division processing: E. Broken line data: (E1) Broken line data structure: (E2) Broken line drawing processing: F. Symbol data with characters: (F1) Symbol data structure with characters: (F2) Symbol drawing process with characters: G. Map matching data: (G1) Map matching data structure: (G2) Link string data retrieval process: Multiple coordinate system graphic data: (H1) Multiple coordinate system graphic data structure: (H2) Graphic drawing processing:

A. Map Display System: FIG. 1 is a schematic configuration diagram of a map display system MS in the present embodiment. The map display system MS includes a server SV having an electronic map database DB, the server SV and the Internet IN.
It is composed of a base station BS connected by T and a mobile phone CP that transmits and receives data to and from the base station BS by wireless communication WL. The mobile phone CP has a CPU, a RAM and an E
It has a built-in EPROM. The EEPROM acquires the map data from the electronic map database DB and displays it on the display unit D.
A program for displaying a map on P is stored.

B. Mobile phone functional block overview:
It is a functional block diagram of mobile phone CP. Mobile phone CP
Includes an operation input unit 10, a map data acquisition unit 11, a main control unit 12, a map data storage unit 13, a drawing unit 14, a display control unit 15, and the like. The operation input unit 10 includes an operation button S
Input the user operation from B. Map data acquisition unit 11
Inputs map data and the like from the server SV according to an instruction from the main control unit 12. The map data storage unit 13 stores the input map data. The drawing unit 14 is the main control unit 1.
Map data is input from the map data storage unit 13 via 2 and a map is drawn on the RAM. The map drawn on the RAM is output to the display unit DP via the display control unit 15.

C. Outline of map data: FIG. 3 is a data configuration diagram of the electronic map database DB. Map data MD and map matching data MM are recorded in the electronic map database DB. In the map data MD, polygon data, broken line data, character-added symbol data MK, etc. are recorded, and a map is represented by these data. The four roads A to D in the figure are polygons each having four vertices, and the building ST is a polygon having seven vertices. Further, the embankment symbol PE is represented by a broken line. On the other hand, the map matching data MM is data used when performing a route search or the like, and the connection state of roads is managed by data called a link string. The link string is composed of node data representing intersections, branch points, etc. on the road. The “●” mark shown in the figure is a node. For example, the link string AA forming the road A is composed of the nodes N1 to N4.

D. Polygon data: (D1) Polygon data structure: FIG. 4 shows map data MD
3 is a data structure diagram of polygon data recorded in FIG. This is a format in which the graphic data of the roads A to D and the building ST shown in FIG. 3 are recorded. It will be described in order from the top of the figure. The number of coordinate points is the number of vertices forming a polygon. Next, the polygon shape type is a parameter indicating the feature of the polygon. A polygon having at least one interior angle exceeding 180 degrees is defined as a concave polygon, and other than that, that is,
All polygons whose interior angles are less than 180 degrees are defined as convex polygons. After that, the X and Y coordinates of the vertices of the polygon are recorded by the number of the coordinate points. The above parameters are parameters commonly recorded in the concave polygon and the convex polygon. When the polygon to be recorded is a concave polygon, the number of dividing line segments and the starting and ending points of the dividing line segments are also recorded. The dividing line segment is a line segment that becomes a “break” for dividing a concave polygon into a set of convex polygons. The starting point and the ending point of the dividing line segment are selected from the above vertices, and are designated by a value indicating the number of recorded vertices. Of course, if a vertex has a number, it may be designated by that number.

(D2) Polygon drawing process: Next, a process in which the mobile phone CP reads polygon data according to the above-mentioned data structure and draws it on the display portion DP will be described.
This is a process performed by the CPU of the mobile phone CP in accordance with the program recorded in the EEPROM. FIG. 5 is a flowchart of polygon drawing processing.

First, the CPU of the mobile phone CP designates the point that the user wants to display on the display portion DP by operating the operation button SB.
And the like (step S100). And C
The PU acquires the map data around the designated point from the electronic map database DB of the server SV via the wireless communication WL and the Internet INT and stores it (step S101). Next, the CPU analyzes whether or not polygon data is recorded in the stored map data (step S102). If it is not recorded, the process is terminated, and if it is recorded, one polygon is read (step S103). Then, it is determined from the polygon shape type parameter whether the polygon is a convex polygon or a concave polygon (step S104). If the polygon is a convex polygon, the polygon is drawn based on the recorded coordinates (step S106). If the polygon is a concave polygon, convex division processing, which will be described later, is performed (step S105), and each divided polygon is drawn (step S106). Next, the CPU returns the processing to step S102, and determines whether or not there is other polygon data. If there is other polygon data, step S
The processing of 103 to S106 is repeated, and if not, the processing ends. Through such processing, polygons are displayed on the display portion DP of the mobile phone CP.

(D3) Convex division processing: Step S10
The convex division processing in 5 will be described. FIG. 6 shows FIG.
It is a figure showing in detail the building ST shown by. Building st
Is represented by a polygon having vertices P1 to P7. As shown in the figure, since the two interior angles α and β are 180 degrees or more, the polygon shape type parameter is a concave polygon. In addition, the start point of the data is P
2 and a dividing line segment 1 whose end point is P6, and a dividing line segment 2 whose start point is P4 and whose end point is P6. Mobile phone CP
On the basis of these dividing line segments, the CPU of FIG. 1 converts the concave polygon into a plurality of convex polygons, that is, the figure a composed of the coordinates P1, P2, P6, and P7, as shown in the lower part of the figure.
a, a figure b composed of coordinates P2, P3, P4, and P6
b and a figure c composed of coordinates P4, P5, P6
Divide into c. Then, in step S106, the CPU of the mobile phone draws on the screen for each of the divided figures.

When the number of vertices of a polygon that can be drawn by the mobile phone CP has an upper limit value, the polygon drawing (step S107) may include a process of further dividing the convex polygon. For example, a process of extracting a convex polygon having the number of vertices exceeding the upper limit value and dividing the polygon along an arbitrary diagonal line until the number of vertices becomes equal to or less than the upper limit value may be performed. As an example, consider a case where the upper limit value is 3 in FIG. In this case, in step S107, the quadrangles aa and bb are further divided into two triangles by the diagonal lines La and Lb, and then drawn.

E. Broken line data: (E1) Broken line data structure: Next, the broken line data representing the embankment symbol PE and the like shown in FIG. 3 will be described. FIG. 7 is a diagram showing a data structure of broken line data. It will be described in order from the top of the figure. The number of coordinate points is the number of coordinates forming a polygonal line. Next, the pen-up information flag is recorded. Pen-up is when you draw the line segments that make up a broken line in sequence.
It means switching from the drawing state to the non-drawing state at the designated coordinates, and the pen-up information flag is a parameter indicating whether or not the information for drawing is included. After that, the coordinates forming the polygonal line are recorded by the number of the coordinate points. Finally, when the pen-up information flag is 1, the number of pen-ups, that is, the number of times pen-up is performed, and a parameter indicating which point of the above-mentioned coordinate point to pen-up are recorded.

FIG. 8 is a diagram showing an example of a polygonal line recorded according to the above data structure. The polygonal line shown is the coordinate P1.
It is composed of ~ P9, the place to pen up,
The third point was P3 and the sixth point was P6. In this embodiment, when the pen is moved up at a certain coordinate, the pen is always moved down at the next coordinate. What is pen down?
Switching from the non-drawing state to the drawing state.

(E2) Broken line drawing process: Next, the mobile phone C
A process in which P reads the polygonal line data recorded according to the above data structure and draws it on the display portion DP will be described.
This is also a process performed by the CPU of the mobile phone CP according to the program recorded in the EEPROM.

FIG. 9 is a flowchart of the polygonal line drawing process. First, the CPU of the mobile phone CP inputs the designation of the point to be displayed on the display unit DP by the user using the operation button SB or the like (step S200). And CPU
Is the wireless communication WL for the map data around the specified point.
And it is acquired from the electronic map database DB of the server SV via the Internet INT and stored (step S201). Next, the CPU analyzes whether or not the stored map data includes broken line data (step S
202), if it is not included, the process is terminated, and if it is included, one piece of broken line data is read (step S20).
3). Then, the state of the pen-up information flag of the broken line data is checked (step S204). If the pen-up information flag is 0, that is, if there is no pen-up information,
A polygonal line is drawn based on the stored coordinate data (step S205). The pen-up information flag is 1, that is,
If there is pen-up information, draw line segments in sequence and jump to the next coordinate at the pen-up point,
Continue drawing line segments. These processes are repeated to draw all line segments (step S206). In this way, when the drawing process in step S205 or step S206 is completed, the CPU executes the process in step S20.
Returning to 2, it is determined whether or not other broken line data is included. If there is other broken line data, steps S203 to S2
The processing of 06 is repeated, and if not, the processing ends.
By such processing, a polygonal line is displayed on the display portion DP of the mobile phone CP.

In the present embodiment, the case where the display / non-display of the line segment is switched by pen-up / pen-down has been illustrated on the assumption that the polygonal line is drawn in the order of the vertices recorded in the data. Switching between display / non-display may be controlled by a flag associated with each line segment. For example, instead of the pen-up information in FIG. 7, a flag indicating that the line segments P3-P4 and P6-P7 are not displayed may be provided.
This mode has an advantage that display / non-display of line segments can be controlled regardless of the drawing order.

F. Character-added symbol data: (F1) Character-added symbol data structure: Next, the character-added symbol data will be described. The character-added symbol data is data for displaying symbols and names of schools, fire stations, post offices, etc. on a map as shown in FIG.

FIG. 10 is a diagram showing the data structure of the character-added symbol data. It will be described in order from the top of the figure. The reference point coordinates X and the reference point coordinates Y are the center coordinates of the symbol to be drawn. The vertical / horizontal flag means that the characters are written vertically or
Alternatively, it is a parameter that specifies whether to write horizontally.
The character array is a parameter that specifies where to draw a character with respect to a symbol. The symbol display level and the character display level are parameters that specify on which map the symbols and characters are drawn. The display level of a map means the level of detail of the map. In this embodiment, the map of display level 1 has the highest level of detail,
The map with display level 5 is the one with the lowest level of detail. As shown in the figure, the values of the symbol display level and the character display level are values that specify the upper limit value of the display level of the map on which the characters / symbols are drawn. Next, the symbol number is a parameter that specifies the symbol to be drawn. The electronic map database DB includes a symbol database in addition to map data, and symbols to be drawn from this database are designated by numbers assigned in advance. Next, the character string size is the length of a character to be drawn. The character to be drawn is stored in the character string.

FIG. 11 shows the relationship between the map display level, the symbol display level, and the character display level described above. Here, the symbol to be displayed is a school mark, the character to be displayed is "northeast small", the symbol display level is 4, the character display level is 2, the character array parameter is 1, and the vertical / horizontal flag is 1. “Display mode” in the figure shows the display result when the character-attached symbol data is set in this way. As shown in the figure, symbols and characters are displayed on the maps of display levels 1 and 2 having a high degree of detail, and only symbols are displayed when the display levels are 3 and 4. Then, nothing is displayed on the display level 5 having the lowest level of detail. Therefore, by using such character-added symbol data, for example, when displaying a map of the entire “city” on the administrative division, neither the symbol nor the characters are displayed, and the entire “ward” is displayed. It is possible to control such that only the symbol is displayed and the symbol and the character are displayed when the map of the "town" level with the highest degree of detail is displayed.

(F2) Character-added symbol drawing process: FIG.
It is a flowchart of the process which displays the said symbol with a character. First, the CPU of the mobile phone CP is
The point to be displayed on P and the designation of the display level are input using the operation buttons SB or the like (step S300). Then, the CPU acquires the map data around the designated point from the electronic map data of the server SV via the wireless communication WL and the Internet and stores it (step S30).
1). Then, the CPU uses the stored map data to draw a map at the display level designated in step S300 (step S302). This is performed by the polygon drawing process, the polygonal line drawing process, and the like described above. In order to draw the map at the designated display level, the polygons or polygonal lines may be drawn by enlarging or reducing the polygons or polygonal lines according to the display level.

Next, the CPU determines whether or not the map data includes the character-added symbol data (step S30).
3). If not included, the process ends. If included, one character-added symbol data is read (step S304), and the display level designated in step S300 is compared with the symbol display level and the character display level recorded in the character-attached symbol data, respectively. Then, it is determined whether or not to draw each (step S305). As a result, if the condition is not satisfied and drawing is not performed, the process returns to step S303, and if the condition is satisfied, the symbol and the character are drawn with the coordinates and arrangement designated by the character-attached symbol data (step S306). .

As described above, the arrangement of characters is specified by the relative positional relationship such as right or left of the symbols. Therefore, the CPU obtains the coordinates for drawing the character by a predetermined calculation from the designation of the vertical writing / horizontal writing of the character string, the size of the character string, and the center coordinates of the symbol.

Then, the process is returned to step S303, and it is determined whether or not the character-attached symbol data is recorded. If there is other character-added symbol data, step S304.
The processes of S306 to S306 are repeated, and if not, the process ends. Through such processing, the display unit D of the mobile phone CP is
A map and a symbol with letters can be displayed on P.

G. Map Matching Data: (G1) Map Matching Data Structure: Next, the map matching data MM shown in FIG. 3 will be described. FIG. 13 is a diagram showing a data structure for storing the map matching data MM. As shown, the map matching data MM includes an index area and an actual data area. The actual data area stores the substance of the link string data, and the index area stores information for designating the start address of the link string data grouped into 32 pieces, that is, index data. There is. The link string data is data with an undefined data length. Originally, if all link string data have one-to-one index data,
You can instantly know which link string is at which address. However, for that reason, the storage area of the index area increases. Therefore, in this embodiment, the link string data is grouped into 32 groups, and each group has index data. In addition,
A series of numbers are assigned to the index data and the link string data. The start address of the actual data area is known, and the index data is an offset value from the start address of the actual data area. For example, the start address of link string data 0 is ad0, and the start address of link string data 32 is ad1.
If it is, the offset value is “ad1-ad
A value of "0" is stored.

Next, the process of searching the address of any link string data from such map matching data MM will be described. For example, in a route search or the like, this is a process used when, when a certain link string intersects another link string, the address of the link string data at the crossing destination is obtained.

FIG. 14 is a flowchart of the link string data search process. This processing is also performed by the CPU of the mobile phone CP.
Is a process performed according to the program recorded in the EEPROM. First, the CPU of the mobile phone CP inputs the number of the link string data to be searched (step S40).
0). Next, it is determined whether the input link string data number is 32 or more (step S401). As a result, when the link string data number is 32 or more, the following calculation is performed (step S402).

Index data number n = link string data number \ 32-1; ("\" is an operator for finding a quotient)

Next, the index value stored in the index data number n obtained by the above calculation is acquired (step S403). This is the start address of the group to which the search target belongs. Link string data number is 0 to 3
In the case of 1, the start address of the actual data area is acquired (step S404) and set as the start address of the group to which the search target belongs. Then, the address value in which the target link string data is stored is searched by sequentially incrementing the address value from the obtained start address (step S405), and the process is terminated. By the above processing,
It is possible to search for the target link string data in a short time without using a relatively low capacity index data.

H. Plural coordinate system graphic data: (H1) Plural coordinate system graphic data structure: Next, the structure of the plural coordinate system graphic data will be described. The plural coordinate system graphic data is data in which a graphic defined by a plurality of continuous point sequences is represented by absolute coordinates and relative coordinates.

FIG. 15 is an explanatory diagram showing the relationship between absolute coordinates and relative coordinates. The polygonal line figure shown in the figure consists of a series of points P1 to P5, the absolute coordinates of which are P1 [X1, Y
1], P2 [X2, Y2], P3 [X3, Y3], P4
[X4, Y4] and P5 [X5, Y5]. When this figure is expressed in relative coordinates, the absolute coordinates of P1 [X1, Y
1] as a reference point, and P2 and subsequent P2 are respectively P2 [ΔX2
1, ΔY21], P3 [ΔX32, ΔY32], P4
[ΔX43, ΔY43], P5 [ΔX54, ΔY54]
It can be expressed as. That is, the difference coordinate value from the point immediately before that point becomes the relative coordinate. The relative coordinates can be either positive or negative. Here, the reference point of the relative coordinates is the immediately preceding point, but it may be any point on the coordinates. For example, the point K in the figure may be used as the reference point. In this case, all the points from P1 to P5 can also be represented by the differential coordinate values from the arbitrary point K on the coordinates, as indicated by the dotted line. Although a single reference point K is illustrated in the figure, a plurality of reference points may be used separately. By appropriately selecting a reference point having a relatively short distance to each point, the data amount of relative coordinates can be suppressed. In the following description, any of these relative coordinates may be used.

FIG. 16 is a diagram showing an example of a schematic structure of graphic data in a plurality of coordinate systems. In the figure, various parameters are described in the order of addresses, and the horizontal width relatively represents the data width of the data to be recorded.

The description starts from the top of the figure. "Total number of coordinates"
Is the total number of coordinate points of the point sequence forming the figure. "Coordinate X
"1" and "coordinate Y1" are the coordinates of the first point of the figure. This coordinate is always recorded in absolute coordinates. Next, the area a will be described. In the "coordinate data type", the recording format of the coordinates recorded after the second point is recorded. This is data representing the format of absolute coordinates, relative coordinates, or, in the case of relative coordinates, how many bits the data width is. Then, the number of coordinates recorded according to the coordinate data type is recorded in the “coordinate number” (m in the case of the figure),
The coordinate data is recorded in the coordinate format designated by the coordinate data type. In the case of the figure, the relative coordinate data is recorded with a data width half the absolute coordinate data. In addition,
Although the data width of the relative coordinates is variable in the present embodiment, it may be fixed.

In the next area b, the relative coordinate data is recorded as in the area a described above. However, the data width of the relative coordinates is set larger than the data width of the area a. This is because the distance between the coordinates of the point sequence forming the figure is larger than that of the data recorded in the area a.

Next, in the area c, data is recorded in absolute coordinates. This is because if the distance between the coordinates is large, the data width also becomes large, and even if the data is recorded in the relative coordinates, the required data amount is the same as in the case of the absolute coordinates. Further, in the case of relative coordinates, an operation of sequentially adding coordinates at the time of drawing is necessary, but such an operation is not necessary for absolute coordinates, so that the processing load of the display device can be reduced.

As described above and as shown in the drawings, the data width of the relative coordinate data can be flexibly set. By doing so, the data width can be reduced when the distance between the coordinates is small, and can be increased when the distance is large. Therefore, the data area can be efficiently used, and the data capacity can be reduced as a whole.

(H2) Graphic drawing process: Next, a process of reading the graphic data of a plurality of coordinate systems recorded according to the above-mentioned data structure and drawing it on the display portion DP will be described. This is also a process performed by the CPU of the mobile phone CP according to the program recorded in the EEPROM. This program
It has a function to draw a polygonal line or a polygon by switching between absolute coordinates and relative coordinates.

FIG. 17 is a flow chart of the processing for drawing the plural coordinate system graphic data. First, the CPU of the mobile phone CP inputs a designation of a point to be displayed on the display unit DP by the user using the operation button SB or the like (step S).
400). Then, the CPU transfers the map data around the designated point to the wireless communication WL and the Internet INT.
It is acquired from the electronic map database DB of the server SV via the and stored (step S401). Next, the CPU
The stored map data is analyzed as to whether or not it contains plural coordinate system graphic data (step S402). If it is not included, the process is terminated, and if it is included, the data is read (step S403). Then, the CPU refers to the coordinate data type parameter and draws a figure while switching between absolute coordinates and relative coordinates. When drawing based on the relative coordinates, the position of the point to be drawn is specified from the relative coordinates given by the data and the absolute coordinates of the reference point (step S404). Then, the process returns to step S402, and it is detected whether or not the map data includes other plural coordinate system graphic data. If there is, another data is read, and steps S403 to S404 are repeated to draw a figure.
If not, the process ends. By such processing, it becomes possible to draw a figure based on figure data in which absolute coordinate data and relative coordinate data are mixed.

The embodiments of the present invention have been described above based on the examples. A polygon according to such an embodiment,
By the data structure of the polygonal line, the symbol with characters, the graphic data of plural coordinate systems, and the drawing process thereof, it is possible to realize an appropriate map display while reducing the capacity of the map data. Further, due to the structure of the map matching data, it is possible to smoothly carry out the route search while using a relatively low capacity data.

However, the present invention is not limited to these embodiments, and various structures can be adopted without departing from the spirit of the present invention. In the embodiment, the process using hardware may be performed by software, or the process using software may be performed by hardware.

The various parameters included in each data structure exemplified in the embodiment do not necessarily have to be provided in all, and some of them may be appropriately combined and applied.

In the embodiment, the map distribution to the mobile phone is illustrated, but the map display device can use various hardware such as a personal computer and a PDA. Further, the map data does not necessarily have to be distributed via the network, but may be supplied by a recording medium such as a CD-ROM or a DVD. This is because the effect of reducing the data capacity by the data structure shown in this embodiment is effective also in storing the map data in the recording medium.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a map display system MS.

FIG. 2 is a functional block diagram of a mobile phone CP.

FIG. 3 is a data configuration diagram of an electronic map database DB.

FIG. 4 is a data structure diagram of polygon data.

FIG. 5 is a flowchart of polygon drawing processing.

FIG. 6 is a diagram showing a building ST in detail.

FIG. 7 is a diagram showing a data structure of broken line data.

FIG. 8 is a diagram showing an example of a broken line.

FIG. 9 is a flowchart of a polygonal line drawing process.

FIG. 10 is a diagram showing a data structure of character-added symbol data.

FIG. 11 is a diagram showing a relationship among a map display level, a symbol display level, and a character display level.

FIG. 12 is a flowchart of a process of displaying a character-added symbol.

FIG. 13 is a diagram showing a data structure for storing map matching data MM.

FIG. 14 is a flowchart of a link string data search process.

FIG. 15 is an explanatory diagram showing a relationship between absolute coordinates and relative coordinates.

FIG. 16 is a diagram showing an example of a schematic structure of graphic data in a plurality of coordinate systems.

FIG. 17 is a flowchart of a process of drawing a plurality of coordinate system graphic data.

FIG. 18 is an explanatory diagram showing division display of a polygon.

[Explanation of symbols]

10 ... Operation input section 11 ... Map data acquisition unit 12 ... Main control unit 13 ... Map data storage unit 14 ... Drawing unit 15 ... Display control unit BS ... Base station CP ... mobile phone DB: Electronic map database DP ... Display INT ... Internet MD ... Map data MK ... Symbol data with letters MM ... Map matching data MS: Map display system SB ... Operation button SV ... server

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Ryuta Yokoyama             1-1 Shimoiritsu, Kokurakita-ku, Kitakyushu City, Fukuoka Prefecture             No. 10 Zenrin Co., Ltd. F term (reference) 2C032 HB06 HB25 HC21 HC24                 2F029 AA02 AB13 AC08 AC09 AC12                       AC14 AD01                 5B050 AA08 BA07 BA17 CA08 EA19                       FA02                 5B075 ND06 PQ69 UU14                 5H180 AA01 BB05 BB12 BB13 FF07                       FF22 FF32

Claims (18)

[Claims] 1. A data structure of graphic data recorded in electronic map data, comprising: polygonal vertex data having at least one interior angle of 180 ° or more; and 180 ° or more of the vertex data. By dividing the polygon into a plurality of polygons each having an interior angle of less than 180 degrees by a line segment having a vertex having an interior angle and another arbitrary vertex as both ends, The recorded data structure. 2. An electronic map display device for displaying an electronic map, which refers to electronic map data in which the data structure according to claim 1 is recorded, and which inputs the vertex data and the dividing line segment data. A data reference unit and a drawing unit that draws a polygon using the vertex data are provided. The drawing unit divides the polygon into a plurality of polygons by the dividing line segment data, and the polygon An electronic map display device that draws each image. 3. A data structure of graphic data recorded in electronic map data, wherein coordinate data for each point sequence forming a polygonal line consisting of continuous line segments and display or non-display of the line segment are designated. A data structure that records display control data in association with. 4. The data structure according to claim 3, wherein the display control data switches a display mode from display to non-display, or from non-display to display when sequentially drawing the continuous line segments. A data structure that is data that identifies points. 5. An electronic map display device for displaying an electronic map, which refers to electronic map data having the data structure according to claim 3, and inputs the coordinate data and the display control data. An electronic map display device comprising: a reference unit; and a drawing unit that switches display / non-display based on the display control data and draws a polygonal line according to the coordinate data. 6. A data structure of symbol data or display character data recorded in electronic map data having map data capable of being displayed in multiple scales, wherein the shape or character string of the symbol to be displayed is specified. The display content data to be displayed, the coordinate data for designating the position where the symbol or the character string is to be displayed, and the display stage data for designating the upper limit value or the lower limit value of the stage for displaying the symbol or the character string are associated with each other. Recorded data structure. 7. An electronic map display device for displaying an electronic map, wherein the display content data, the coordinate data, and the electronic map data having the data structure according to claim 6 are referenced.
A map data reference unit for inputting the display stage data, a stage designation unit for designating a scale of a map to be displayed, and when the designation of the stage satisfies the condition specified by the display stage data, An electronic map display device comprising: a drawing unit that draws the symbol or the character string based on the display content data and the coordinate data. 8. A data structure of an object group recorded in electronic map data, comprising an object area for holding a plurality of objects in a continuous address space, the object area being a delimiter of the objects,
A data structure that is divided into a plurality of object groups, and has an index area for holding index data that specifies a start address of the object group, separately from the object area. 9. An object retrieval device for retrieving an object recorded in electronic map data, comprising a reference unit for referring to the electronic map data having the data structure according to claim 8 and an object to be retrieved. A search target input unit that inputs an index for specifying; an index data search unit that searches the index region for index data indicating a start address of an object group to which the search target belongs; and in the object region, the index An object search device comprising: a sequential search unit that sequentially searches from addresses recorded in data and searches for a search target. 10. A data structure of graphic data recorded in electronic map data and defined by a plurality of continuous point sequences, wherein absolute coordinate data holding coordinates of a part of the point sequence by absolute coordinates, Relative coordinate data for holding the coordinates of the remainder of the point sequence by relative coordinates from a predetermined reference point, recorded in the boundary between the area in which the absolute coordinate data is recorded and the area in which the relative coordinate data is recorded, A data structure that specifies the type of coordinate data of the area recorded in 1., the range that the relative coordinate data can take is narrower than the range that the absolute coordinate data can take. 11. The data structure according to claim 10, wherein the type designation data includes a parameter that designates a possible range of the relative coordinate data. 12. An electronic map display device for displaying an electronic map, wherein the absolute coordinate data, the relative coordinate data, and the type are referenced with reference to electronic map data having the data structure according to claim 10. A map data reference unit for inputting designated data, an absolute coordinate specifying unit for specifying the position of a point to be drawn based on the absolute coordinate data, and a point to be drawn based on the relative coordinate data and the absolute coordinates of the reference point. An electronic map display device, comprising: a relative coordinate specifying unit that specifies the position of the position; and a drawing unit that draws the graphic by switching between the absolute coordinate specifying unit and the relative coordinate specifying unit based on the type specifying data. 13. A computer program for causing a computer to realize a function of displaying an electronic map on an electronic map display device, the electronic map data having the data structure according to claim 1 recorded therein, the vertex data being referred to. And a map data reference function for inputting the dividing line segment data, and a drawing function for drawing a polygon using the vertex data,
The drawing function is a computer program that divides the polygon into a plurality of polygons by the dividing line segment data and draws each polygon. 14. A computer program for causing a computer to realize a function of displaying an electronic map on an electronic map display device, wherein the coordinate data is referred to by referring to electronic map data having the data structure according to claim 3. A computer program having a map data reference function of inputting the display control data and a display function of switching display / non-display based on the display control data and drawing a polygonal line according to the coordinate data. 15. A computer program for causing a computer to realize the function of displaying a character or a symbol on an electronic map display device, the electronic map data having the data structure according to claim 6 recorded therein, and the display being performed. Content data, the coordinate data,
A map data reference function for inputting the hierarchical range data, a stage designation function for designating a scale of a map to be displayed, and when the designation of the stage satisfies the condition specified by the display stage data, And a drawing function for drawing the symbol or the character string based on the display content data and the coordinate data. 16. A computer program for causing a computer to realize a function of retrieving an arbitrary object from electronic map data, the reference function referring to electronic map data having the data structure according to claim 8, A search target input function of inputting an index for specifying an object to be searched; an index data search function of searching index data indicating a start address of an object group to which the search target belongs from the index area; A computer program having a sequential search function of sequentially searching within the area from addresses recorded in the index data to search for a search target. 17. A computer program for causing a computer to realize a function of displaying an electronic map on an electronic map display device, wherein the absolute coordinates are referred to by referring to electronic map data having a data structure according to claim 10. Map data reference function for inputting data, the relative coordinate data, and the type designation data, an absolute coordinate specifying function for specifying a position of a point to be drawn based on the absolute coordinate data, the relative coordinate data and the Relative coordinate specifying function for specifying the position of the point to be drawn based on the absolute coordinates of the reference point, and drawing for switching the absolute coordinate specifying section and the relative coordinate specifying section based on the type specifying data to draw the figure A computer program having the following functions. 18. Claims 1, 3, 4, 6, 8, 10, 1
A computer-readable recording medium recording any one of the electronic map data holding the data structure according to claim 1 and the computer program according to claims 13 to 17.