JPH0869525A - Vector data conversion method and conversion device - Google Patents

Abstract

(57) [Abstract] [Object] The present invention relates to a method and apparatus for converting vector data, and a method and a method that enable a computer having a low ability to use the original data to operate lightly. The purpose is to provide a device. [Structure] The conversion source data in which a plurality of straight line vectors are sequentially connected in a polygonal line shape is read, and the bending angle at each vector connection portion is compared with the reference angle for thinning out from the read conversion source data. The vector connected portion for which the comparison result indicating that is obtained is passed and the converted data in which the vector connected portions on both sides adjacent to this portion are connected by a straight line vector are generated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for converting vector data.

[0002] For example, when bringing a map to the site for investigating the condition of a road, the number of required maps generally increases, and the efficiency of the survey work decreases. For this reason,
The map data is stored on the host computer side, the map data is converted and transferred to a mobile computer, and the research staff carries the computer to the site.

[0003]

2. Description of the Related Art Many terminals are connected to a host computer, each terminal creates map data and stores it in a hard disk of the host computer.

This map data includes vector data indicating roads and the like and character data indicating place names and the like. From the data of the map portion necessary for on-site inspection, data indicating vector coordinates is sent from the host computer side. Take it out and move it to a portable computer, and a researcher will take the computer to the site.

[0005]

However, in many cases, the precise map data is accumulated in the host computer, and the amount of coordinate data transferred to the portable computer becomes too large for the portable computer (portable computer). Has a low CPU capacity, and the capacity of main memory and disk is limited), and it becomes difficult to display the map at a sufficient speed in the field.

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to provide a conversion method and apparatus capable of reducing the weight of original data.

[0007]

[Means for Solving the Problems]

First invention: The conversion source data having the content in which a plurality of straight line vectors are sequentially connected in a polygonal line shape is read (step 10).
0), comparing the bending angle in each vector connection portion with the read-out source data with the reference angle for thinning (step 102), the vector connection portion for which a comparison result indicating that the bending angle is slight is obtained is obtained. Conversion destination data is generated by passing the vector connection parts on both sides adjacent to the part by a straight line vector (step 104).

Second invention: A conversion source data storage means 10 for storing conversion source data having a plurality of linear vectors successively connected in a polygonal line shape, and the conversion source data is read to move from one end of the vector connection to the other end. Vector coordinate point acquisition means 12 for sequentially acquiring all the end coordinates of the straight line vector, angle comparison means 14 for comparing an intersection angle of two line segments formed by three consecutive coordinates in the acquisition order with a reference angle for thinning, and an intersection angle. With the reference angle being less than the reference angle, the conversion destination data generating means 16 for generating the conversion destination data having the contents in which the coordinates of the line segment intersection are deleted from the acquisition coordinates, and the thinning reference angle setting for setting the reference angle for thinning according to a given instruction. Means 18 and.

[0009]

As will be understood from FIG. 1, the conversion-destination data is generated by linearizing the conversion-source data having a small bending angle of the vector connection portion. In the second invention, it is possible to arbitrarily set the angle serving as the reference of conversion, if necessary.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 3 shows the configuration of the embodiment, in which a host computer 30 has a number of terminals 32 connected to a network 3.
4 are connected.

A hard disk 36 is provided in the host computer 30, and precise road map data is created in each terminal 32 and then stored in the hard disk 36.

Then, the manager of this map data or the person in charge of the field survey operates one of the online terminals 32,
The data of the necessary map portion is converted, and the lightened data is written to the floppy disk 38. In addition,
The mobile terminal 40 may be connected to the terminal 32 and the data converted from the terminal 32 to the mobile terminal 40 may be downloaded.

Each staff member of the field survey carries the floppy disk and the offline portable terminal 40 in place of many maps or atlases, and operates the portable terminal 40 to display the map data written in the floppy disk 38. The content is displayed on the mobile terminal 40.

In FIG. 4, the processing procedure of this embodiment is described with reference to a flow chart. In addition, FIG.
The operation of this embodiment is described in (B), (C), (D), and (E).

The administrator of the map data stored in the hard disk 36 or the person in charge of the field survey operates one of the online terminals 32 to first set an allowable angle (reference angle for thinning) (step 400) and convert the data. To execute. The amount of data reduction changes according to this allowable angle.

In FIG. 5A, the conversion source data is described. The conversion source data is a series of four straight line vectors connected in a polygonal line, and the coordinate a is the starting point and the coordinates b,
Let c and d be vector connection parts, and coordinate e be the end point.

In FIG. 4, when the allowable angle is set (step 400), three coordinates are acquired from the conversion source data and the coordinates of the first point are stored in the work area (step 402).

In the case of the conversion source data shown in FIG. 5A, the coordinates a, b, c are acquired in order, and the coordinate a is stored as a first point in the work area. Next, the angle at which two straight lines passing through the coordinates of these three points intersect is calculated (step 404).

This crossing angle is explained in FIG. 5 (B), and when the coordinates a, b, c in FIG. 5 (A) are acquired, a straight line vector from the coordinates a to b and coordinates b to c. Find the intersection angle of the straight line vectors.

Then, this intersection angle is compared with the already set allowable angle (step 406), and when the calculated intersection angle is less than or equal to the allowable angle (YES in step 406).
Sets the coordinates of the third point to the second point (step 40
8) and obtain the next coordinate and make it the third point (step 41).
0), the intersection angle is calculated again and compared with the allowable angle (steps 404 and 406).

If the intersection angle is not less than the allowable angle (NO in step 406), the coordinates of the second point are stored in the work area (step 412), and the coordinates of the second point are set as the first point and the third point. The coordinate of is set as the coordinate of the second point (step 414), the next coordinate is acquired and set as the third point (step 410), and the intersection angle is calculated again and compared with the allowable angle (steps 404 and 406).

The above processing is carried out in parallel for all the data whose straight line vectors are successively connected on the polygonal line, and when it is confirmed that all the coordinates have been obtained (N at step 416).
O), the coordinates stored in the work area and the coordinates of the second point are written to the floppy disk 38 (step 41).
8).

In the case of the conversion source data shown in FIG. 5A, the case where the intersection angle at the coordinates b and c is less than or equal to the allowable angle will be described. When the coordinates a, b and c are acquired, the intersection angle at the coordinate b is obtained. Since it can be confirmed that is less than or equal to the allowable angle, the coordinate c of the third point is the second point and the next coordinate d is the third point as shown in FIG. Next, since the intersection angle at the coordinate c is also less than or equal to the allowable angle, FIG.
As in (D), the coordinate d is the second point and the coordinate e is the third point.

Here, since the crossing angle at the coordinate d of the second point is not less than the allowable angle, as shown in FIG.
The coordinate d of the point is stored as the first point, and the coordinate e of the third point is the second point.

At this time, if it is confirmed that there is no next coordinate, a and d stored in the work area and the coordinate e of the second point are stored.
Write out. Therefore, the conversion destination data in which the intermediate coordinates b and c with a slight vector bending angle are deleted from the conversion source data are written to the floppy disk 40.

Therefore, each mobile terminal 40 can display the map lightly and at a sufficient speed, and the local investigator can efficiently and comfortably perform the work.

[0027]

As described above, according to the present invention, since the conversion destination data in which the amount of the conversion source data is reduced can be obtained, the processing can be performed at higher speed on the computer having a low ability to use the conversion destination data. Therefore, it is possible to improve the efficiency of the work in which the computer is used.

[Brief description of drawings]

FIG. 1 is a diagram illustrating the principle of the first invention.

FIG. 2 is a diagram illustrating the principle of the second invention.

FIG. 3 is a diagram illustrating a configuration of an example.

FIG. 4 is a flowchart illustrating a process of an embodiment.

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

[Explanation of symbols]

 30 host computer 32 terminal 34 network 36 hard disk 38 floppy disk 40 mobile terminal

Claims (2)

[Claims] 1. A read source of conversion source data in which a plurality of straight line vectors are sequentially connected in a polygonal line shape, a bend angle in each vector connection portion is compared with a reference angle for thinning out from the read source data, and a bend angle is obtained. The vector data characterized by passing the vector connection part for which the comparison result indicating that the number is small is passed and connecting the vector connection parts on both sides adjacent to the part with the straight line vector to generate the conversion destination data. Conversion method. 2. A conversion source data storage unit for storing conversion source data having a content in which a plurality of straight line vectors are sequentially connected in a polygonal line form, and an end of the straight line vector which is read from the conversion source data and goes from one end of the vector connection to the other end. Vector coordinate point acquisition means for acquiring all the coordinates in order, angle comparison means for comparing the intersection angle of two line segments formed by three consecutive coordinates in the acquisition order with the reference angle for thinning, and the intersection angle is less than or equal to the reference angle. A conversion destination data generating means for generating conversion destination data with the contents of the line segment intersection deleted from the acquisition coordinates, and thinning reference angle setting means for setting a reference angle for thinning according to a given instruction, An apparatus for converting vector data.