JP2013033153A - Proper error span specification device and method for altitude data, computer program for specifying proper error span, and recording medium with computer program recorded - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the proper error span specification device and method of altitude data.SOLUTION: From a map data storage part, a spot on a road link as a specification object of the proper error span of an altitude value is extracted, and on the basis of the mesh altitude data, the altitude value of the object spot is calculated, and as for the altitude value of the object spot, a first error span is calculated on the basis of accuracy relating to the altitude value, and on the basis of road attribute information relating to an inclination set for the road link and the reference altitude data of the other spot on the road link, a second error span of the object spot is calculated, and the overlapped part of the first error span and the second error span is specified as the proper error span of the object spot.

Description

  The present invention relates to an apparatus for specifying an appropriate error width of altitude data and a method thereof.

2. Description of the Related Art In recent years, in navigation devices that perform route search, a technology for calculating the energy consumption amount using road gradient data has been proposed due to an increasing demand for route search technology considering energy consumption amount.
As such a technique, in Patent Document 1, a vehicle route for calculating an estimated fuel consumption in each link based on road gradient data stored for each link and performing an optimum route search using the calculated estimated fuel consumption. Search devices and the like have been proposed.
Since the road gradient data is generally determined based on the elevation value of a predetermined point (coordinate) on the link, it is preferable to use an accurate elevation value. And the said altitude value is maintained in various databases, such as the altitude data acquired based on the altitude data acquired by the measurement vehicle, and mesh altitude data, for example.

Japanese Patent No. 3551634

As described above, the altitude data used for calculating the road gradient data includes altitude data obtained from the measurement vehicle, altitude data obtained based on the mesh altitude data, and the like.
Here, since the database composed of the altitude data acquired by the measuring vehicle acquires the altitude of the road by actually running the measuring vehicle, the accuracy of each altitude data is high. However, since the database actually runs the measuring vehicle, it takes man-hours, cost, and time, and is currently not extensively maintained.

On the other hand, a database composed of elevation data obtained from the above mesh elevation data is composed of elevation data calculated using mesh elevation data provided by the Geospatial Information Authority of Japan. It is possible to maintain altitude data over a wide range without the need for special.
Here, the mesh elevation data is elevation data provided by the Geographical Survey Institute as described above, and is available in the form of a recording medium such as a CD-ROM as in the case of the navigation software. An arbitrary point included in a given area in the map data is divided into small square areas with a side length of about 50m or 10m, and general points are based on the altitude (mesh elevation data) of four grid points surrounding this point. In particular, it can be determined by a linear interpolation method. That is, the elevation value of the predetermined point is specified based on the mesh elevation data of the four lattice points surrounding the point.

However, the altitude data obtained in this way includes human error, survey error, calculation error, etc. due to various factors, so the error range is large, and the altitude data is used as it is It was difficult to calculate road gradient data with high accuracy.
Therefore, the present inventor has intensively studied to specify an appropriate error width for the altitude data obtained based on the mesh altitude data. As a result, at a certain point on the road link, based on the error width due to the accuracy related to the altitude value and the error width considering the road attribute information related to the gradient set for the road link, By specifying the overlapping portion as an appropriate error width, it was conceived that a more appropriate appropriate error width can be obtained.

The present invention has been made in view of the above-described problems, and the first aspect thereof is defined as follows. That is,
From the map data storage unit, a target point extraction unit that extracts a point on the road link that is the target of specifying the appropriate error range of the altitude value,
Based on mesh elevation data, an elevation value calculator that calculates the elevation value of the target point;
A first error width calculation unit that calculates a first error width based on the accuracy associated with the elevation value for the elevation value of the target point;
A second error width calculation unit that calculates a second error width of the target point based on road attribute information related to the gradient set in the road link and reference elevation data of other points on the road link When,
An appropriate error width specifying unit for specifying an overlapping portion of the first error width and the second error width as an appropriate error width at the target point;
An appropriate error width specifying device comprising:

According to the elevation value specifying device of the first aspect defined as described above, a target point on a road link that is a target for specifying an appropriate error width of the elevation value is extracted, and the target point of the target point is extracted based on mesh elevation data. The altitude value is calculated, and the first error width calculated based on the accuracy related to the calculated altitude value and the second error width calculated based on the road attribute information related to the gradient set for the road link. The overlapping part is specified as the appropriate error width of the target point.
In this way, the first error width resulting from the accuracy related to the altitude value and the second error width resulting from the gradient information of the road link are respectively obtained, and the overlapping portion is set as the appropriate error width of the altitude value at the point. As a result, a more probable error range can be specified.

Here, the “first error width” is calculated based on the accuracy related to the altitude value. The accuracy related to the altitude value is not particularly limited as long as the accuracy affects the altitude value, and examples include the accuracy of the mesh altitude database and the map accuracy.
According to the former, since the mesh elevation data is data obtained by measuring the elevation at the node of the mesh, when the target point is located at the node of the mesh, the elevation at the target position can be accurately acquired. . On the other hand, when the target point is not located at a node of the mesh, an error occurs in the elevation value obtained from the four mesh elevation data surrounding the target point. Further, the error that occurs in this manner varies depending on the type of mesh elevation data to be used. That is, for example, the error range of elevation values obtained using higher accuracy 5 m mesh elevation data is the error range of elevation values obtained using relatively low accuracy mesh elevation data such as 10 m mesh elevation data. Narrower than that.

  According to the latter, it is said that the position accuracy of the map has an error of more than a dozen meters due to human error, survey error and the like. Accordingly, when the position of the target point is shifted in the horizontal direction based on the error, the altitude value also has an error width. And the error which arises in this way changes with kinds of map. That is, for example, when a more accurate city map is used, the horizontal position shift is smaller than when a relatively inaccurate topographic map is used. It is considered narrow.

  The “second error width” is calculated based on the road attribute information regarding the gradient set for the road link and the reference altitude data of other points on the road link. Generally, the road gradient is set by a road structure ordinance or the like. Therefore, the elevation value of the target point located on the road link is the error range obtained based on the elevation value (reference elevation data) of other points located on the same road link and the gradient information set for the road link. It is estimated that it is contained within.

The reference altitude data may include the first error width calculated by the first error width calculation unit (third aspect). By using the reference altitude data including the first error width, it is possible to obtain a second error width that is more realistic with respect to the target point.
The appropriate error width specifying unit may specify the appropriate error width of the target point in order based on the reference elevation data having a small first error width (fourth aspect). By specifying the appropriate error width of the target point in order based on the reference altitude data having a small first error width, it is possible to speed up the processing.

The second aspect of the present invention is defined as follows. That is,
In the appropriate error width specifying apparatus defined in the first aspect, a 1-1 error width calculation unit that calculates a 1-1 error width resulting from the mesh elevation data source accuracy of an elevation value at the target point; ,
A 1-2 error width calculation unit for calculating a 1-2 error width due to the position accuracy of the target point,
The first error width calculator calculates the first error width by adding the 1-1 error width and the 1-2 error width.
According to the elevation value specifying device of the second aspect defined in this way, when calculating the first error width, the 1-1st elevation resulting from the mesh elevation data source accuracy of the elevation value at the target point. Since the error width and the 1-2 error width due to the position accuracy of the target point are taken into account, the first error width that is more realistic can be obtained.

The fifth aspect of the present invention is defined as follows. That is,
A target point extraction step for extracting a point on a road link that is a target for specifying an appropriate error width of the altitude value from the map data storage unit;
An altitude value calculating step for calculating an altitude value of the target point based on mesh altitude data;
A first error width calculating step for calculating a first error width based on the accuracy associated with the elevation value for the elevation value of the target point;
A second error width calculating step of calculating a second error width of the target point based on road attribute information relating to the gradient set in the road link and reference elevation data of other points on the road link; When,
An appropriate error width specifying step for specifying an overlapping portion of the first error width and the second error width as an appropriate error width at the target point;
A method for specifying an appropriate error width.
According to the fifth aspect of the invention thus defined, the same effects as those of the first aspect can be achieved.

The sixth aspect of the present invention is defined as follows. That is,
In the appropriate error width specifying method defined in the fifth aspect, a 1-1 error width calculating step of calculating a 1-1 error width resulting from the mesh altitude data source accuracy of the altitude value at the target point; ,
A 1-2 error width calculating step for calculating a 1-2 error width resulting from the position accuracy of the target point,
In the first error width calculating step, the first error width is calculated by adding the 1-1 error width and the 1-2 error width.
According to the sixth aspect of the invention thus defined, the same effects as those of the second aspect can be achieved.

The seventh aspect of the present invention is defined as follows. That is,
In the appropriate error width specifying method defined in the fifth or sixth aspect, the reference elevation data includes the first error width calculated in the first error width calculation step.
According to the seventh aspect of the invention thus defined, the same effect as the third aspect can be obtained.

The eighth aspect of the present invention is defined as follows. That is,
In the appropriate error width specifying method defined in the seventh aspect, the appropriate error width specifying step specifies an appropriate error width of the target point in order based on the reference altitude data having a small first error width.
According to the invention of the eighth aspect defined in this way, the same effects as in the fourth aspect are achieved.

Furthermore, the ninth aspect of the present invention is defined as follows. That is,
A computer program for specifying an appropriate error width, wherein a computer is
From the map data storage unit, target point extraction means for extracting a point on the road link that is a target for specifying the appropriate error width of the altitude value,
An altitude value calculating means for calculating an altitude value of the target point based on mesh altitude data;
A first error width calculating means for calculating a first error width based on the accuracy associated with the elevation value for the elevation value of the target point;
Second error width calculation means for calculating a second error width of the target point based on road attribute information related to the gradient set in the road link and reference elevation data of other points on the road link When,
An appropriate error width specifying means for specifying an overlapping portion of the first error width and the second error width as an appropriate error width of the target point;
As a computer program.
According to the ninth aspect of the invention thus defined, the same effects as those of the first aspect can be achieved.

The tenth aspect of the present invention is defined as follows. That is,
In the computer program defined in the ninth aspect, the computer is further
1-1 error width calculation means for calculating a 1-1 error width resulting from the mesh elevation data source accuracy of the elevation value at the target point;
Function as a 1-2 error width calculation means for calculating a 1-2 error width due to the position accuracy of the target point,
The first error width calculation means calculates the first error width by adding the 1-1 error width and the 1-2 error width.
According to the tenth aspect of the invention thus defined, the same effects as those of the second aspect can be achieved.

The eleventh aspect of the present invention is defined as follows. That is,
In the computer program defined in the ninth or tenth aspect, the reference elevation data includes a first error width calculated by the first error width calculation means.
According to the eleventh aspect of the invention thus defined, the same effects as in the third aspect can be achieved.

The twelfth aspect of the present invention is defined as follows. That is,
In the computer program defined in the eleventh aspect, the appropriate error width specifying unit specifies the appropriate error width of the target point in order based on the reference elevation data having a small first error width.
According to the twelfth aspect of the invention thus defined, the same effects as in the fourth aspect are achieved.

  A recording medium for recording a computer program defined in any of the ninth to twelfth aspects is defined as a thirteenth aspect.

It is a block diagram which shows the structure of the appropriate error width specific | identification apparatus of embodiment of this invention. In the appropriate error width specifying device of the present invention, (A) a schematic diagram showing a first error width, (B) a schematic diagram showing a second error width, and (C) a schematic diagram showing an appropriate error width. It is a flowchart which shows operation | movement of the appropriate error width identification apparatus of embodiment of this invention. The computer program which comprises the appropriate error width specific | identification apparatus of embodiment of this invention is shown. It is a block diagram which shows the structure of the approximate elevation value specific | specification apparatus using the suitable error width specified by the appropriate error width specific | specification apparatus of this invention. It is a schematic diagram which shows the procedure which specifies an approximate altitude value with an approximate altitude value specifying device.

An appropriate error width specifying device according to an embodiment of the present invention will be described.
FIG. 1 shows a schematic configuration of the appropriate error width specifying device 1. This will be described below with reference to the schematic diagram shown in FIG.
As shown in FIG. 1, this appropriate error width specifying device 1 includes a map data storage unit 3, a mesh elevation data storage unit 4, a road gradient information storage unit 5, a target point extraction unit 6, a first storage unit 7, an elevation value. Arithmetic unit 8, second storage unit 9, first error width calculation unit 10, third storage unit 11, second error width calculation unit 12, fourth storage unit 13, appropriate error width specification unit 14, and fifth storage Part 15 is provided.

Map information is stored in the map data storage unit 3. The map information includes information about road elements for defining map information such as links and nodes, information drawn on the map, and the like, and includes source information of the map.
The mesh elevation data storage unit 4 stores mesh elevation data. As the mesh elevation data, for example, 10 m mesh elevation data can be stored, and is configured in association with the source information of the mesh elevation data.

The road gradient information storage unit 5 stores road gradient information in association with links. The road gradient information is gradient information set for the link, and includes, for example, the maximum longitudinal gradient of the road defined by the road structure ordinance.
The target point extraction unit 6 refers to the map data storage unit 3 and extracts a point on the road link that is a target for specifying an appropriate error width of the altitude value as a target point (point P shown in FIG. 2A). The extraction method is not particularly limited. For example, a point on a link existing in an area arbitrarily selected from the map data can be automatically extracted. Further, as another method, it may be designed to allow the operator to manually extract the target point. The extracted target point is stored in the first storage unit 7.

The elevation value calculation unit 8 refers to the mesh elevation data storage unit 4 and calculates the elevation value (elevation value Pz) of the target point extracted by the target point extraction unit 6. The calculation method can be determined by a linear interpolation method based on four mesh elevation data surrounding the target point. The calculated altitude value is stored in the second storage unit 9 in association with the coordinates of the target point.
The first error width calculation unit 10 refers to the map data storage unit 3 and the mesh elevation data storage unit 4, and the first error width related to the elevation value stored in the second storage unit 9 (the same as the error The width A) is calculated. The calculation method of the first error width is not particularly limited as long as the error width based on the accuracy related to the elevation value can be calculated for the elevation value of the target point. The first error width calculation unit 10 may include a 1-1 error width calculation unit 101, a 1-2 error width calculation unit 102, and a calculation unit 103.

The first-first error width calculation unit 101 refers to the mesh elevation data storage unit 4 and is based on the source accuracy of the mesh elevation data used by the elevation value calculation unit 8 to calculate the elevation value of the target point P. An error width of −1 is calculated. For example, the error range of 1-1 may be set to an error range (for example, ± 15 m) determined in advance for each type of mesh elevation data around the elevation value Pz of the target point P.
The first-second error width calculation unit 102 refers to the map data storage unit 3 and calculates the error range of the horizontal position based on the source accuracy (position accuracy) of the map data used for specifying the position of the target point P. Further, referring to the mesh altitude data storage unit 4, the altitude value within the error range of the horizontal position is calculated to obtain the minimum altitude value and the maximum altitude value, and based on the altitude value Pz of the target point P, The range from the minimum altitude value to the maximum altitude value is defined as a 1-2 error width (for example, -5 to 15 m with reference to Pz).
The calculation unit 103 adds the above-described 1-1 error width (for example, ± 15 m) and the 1-2 error width (for example, −5 to 15 m with reference to Pz) to calculate the target point P. A first error width (for example, -20 to 30 m) is calculated around the altitude value Pz. The calculation unit 103 may simply add the 1-1 error width and the 1-2 error width as described above, or add a value obtained by multiplying each error width by an arbitrary coefficient. It's also good. The calculated first error width is stored in the third storage unit 11 in association with the coordinates of the target point.

  The second error width calculation unit 12 refers to the road gradient information storage unit 5 and refers to the second error width related to the elevation value stored in the second storage unit 9 (error width shown in FIG. 2B). B) is calculated. The second error width calculation method is not particularly limited as long as the error width reflecting the road attribute information related to the gradient set on the road can be calculated for the elevation value of the target point. For example, as shown in FIG. 2B, a point Q on the same road link as the target point P is extracted, and the reference altitude data (the altitude value Qz) of the point Q and the road link are set. Based on the road attribute information on the gradient (same as the gradient d °), the second error width allowed in the design of the road can be calculated. Here, the reference altitude data Qz may be an altitude value at the point Q or may be altitude data including the first error width in the altitude value at the point Q. The calculated second error width is stored in the fourth storage unit 13 in association with the coordinates of the target point.

The appropriate error width specifying unit 14 refers to the third storage unit 11 and the fourth storage unit 13 and specifies the appropriate error width in the elevation value of the target point. The method for specifying the appropriate error width is not particularly limited. For example, an overlapping portion of the first error width A and the second error width B is determined as an appropriate error width (error width C shown in FIG. 2C). Can be specified. Here, when the reference altitude data includes the first error width, the appropriate error width specifying unit 14 sequentially determines the appropriate error width of the target point based on the reference altitude data having the smallest first error width. Can be specified. The specified appropriate error width is stored in the fifth storage unit 15 in association with the coordinates of the target point.
In this apparatus 1, the first error width calculation unit 10 and the second error width calculation unit 12 are performed in parallel. However, the first error width calculation unit 10, the second error width calculation unit 12, May be performed in series.

The operation of the appropriate error width specifying device 1 shown in FIG. 1 will be described with reference to FIG.
First, in step 1, the map data storage unit 3 is referred to, and the target point P that is a target for specifying the appropriate error width is extracted and stored.
In step 3, the altitude value of the target point P extracted in step 1 is calculated and stored with reference to the mesh altitude data storage unit 4.
In step 5, referring to the mesh elevation data storage unit 4, an error range (for example, ± 15 m) associated with the type of mesh elevation data used in calculating the elevation value of the target point in step 3 is set as 1-1. Is calculated as the error width.

In step 7, the map data storage unit 3 is referred to, and an error range of the horizontal position associated with the type of map data used in specifying the position of the target point P in step 1 is obtained.
In step 9, the mesh elevation data storage unit 4 is referred to, and the altitude value within the horizontal position error range with respect to the target point P obtained in step 7 is calculated to obtain the minimum altitude value and the maximum altitude value. A range from the minimum elevation value to the maximum elevation value is defined as an error width of 1-2 (for example, -5 to 15 m with reference to Pz).
In Step 11, the 1-1 error width calculated in Step 5 and the 1-2 error width calculated in Step 9 are added to obtain a first error width A (for example, -20 to 30 m). ) And save.

In step 13, a point Q located on the same road link as the target point P is designated.
In step 15, the altitude value (reference altitude data) of the point Q designated in step 13 is calculated with reference to the mesh altitude data storage unit 4.
In step 17, based on the gradient information stored in the road gradient information storage unit 5 and the reference elevation data of the point Q calculated in step 15, the second error width B at the target point P is calculated and stored. .
In step 19, the first error width A calculated in step 11 is compared with the second error width B calculated in step 17, and the overlapping portion is identified as the appropriate error width C at the target point P. ,save.

FIG. 4 is a block diagram showing a hardware configuration of the appropriate error width specifying device 1.
The hardware configuration of the apparatus 1 is such that various elements are coupled to the central controller 221 via the system bus 222 in the same manner as a general computer system.
The central controller 221 includes a general-purpose CPU, a memory controller, a bus controller, an interrupt controller, and a DMA (direct memory access) device. The system bus 222 also includes a data line, an address line, and a control line. A memory circuit including a RAM (Random Access Memory) 223 and a nonvolatile memory (ROM 224, CMOS-RAM 225, etc.) is connected to the system bus 222. Data stored in the RAM 223 is read or rewritten by the central controller 221 or other hardware elements. The data in the non-volatile memory is read-only, and the data is not lost when the device is turned off. The system program for controlling the hardware is stored in the hard disk device 227 and also stored in the RAM 223, and is read and used by the central control device 221 as appropriate via the disk drive control device 226. The hard disk device 227 has an area for storing a computer program for operating a computer system having a general configuration as the appropriate error width specifying device 1.
A predetermined area of the hard disk device 227 is allocated for a storage unit that stores the specified result of the appropriate error width specifying unit 14.
Other areas of the hard disk device 227 are allocated for the map data storage unit 3, the mesh elevation data storage unit 4, and the road gradient information storage unit 5.

Connected to the system bus 222 are a flexible drive control device 231 that reads and writes data from and to the flexible disk 232, and a CD / DVD control device 233 that reads data from the compact disk 234. In this example, a printer 238 is connected to the printer interface 237.
A keyboard / mouse control device 241 is connected to the system bus 222 to enable data input from the keyboard 242 and the mouse 243. A monitor 245 is connected to the system bus 222 via the monitor control device 244. The monitor 245 can be a CRT type, a liquid crystal type, a plasma display type, or the like.
An empty slot 251 is prepared in order to allow the addition of various elements (such as a modem).

  Programs (OS program, application program (including those of the present invention)) necessary for operating the appropriate error width specifying device 1 composed of this computer system are installed in the system via various recording media. . For example, it is possible to install in the form of a non-write recording medium (CD-ROM, ROM card, etc.), a writable recording medium (FD, DVD, etc.), or a communication medium using the network N. Of course, these programs can be written in advance in the nonvolatile memories 224 and 225 and the hard disk device 227.

The appropriate error width specified by the appropriate error width specifying device 1 can be used as it is for specifying the approximate altitude value at the target point.
FIG. 5 is a block diagram of the approximate elevation value specifying device 41 according to the embodiment of the present invention. The approximate altitude value specifying device 41 specifies the approximate altitude value at the target point by using the appropriate error width specified by the appropriate error width specifying device 1. This will be described below with reference to the schematic diagram shown in FIG.

That is, the approximate elevation value specifying device 41 includes a control unit 410, a memory unit 411, an input unit 412, an output unit 413, an interface unit 414, an appropriate error width storage unit 415, a map data storage unit 416, and a mesh elevation data storage unit 417. , Target link selection unit 418, 3D link formation unit 419, reference line formation unit 420, first broken point planned coordinate determination unit 421, first approximate broken line specifying unit 422, second broken point planned coordinate determination unit 423, A second approximate broken line specifying unit 424, an approximate altitude value specifying unit 425, and an approximate altitude storing unit 426 are provided.
The control unit 410 is a computer device including a CPU, a buffer memory, and other devices, and controls other elements constituting the approximate altitude value specifying device 41.
A computer program is stored in the memory unit 411, and this computer program is read into the control unit 410, which is a computer device, and causes it to function. This computer program can be stored in a general-purpose medium such as a DVD.

The input unit 412 is used to select a target link or the like. As the input unit 412, a touch panel type input device that cooperates with the display content of the display can be used.
The output unit 413 includes a display, and displays other information such as an input screen, map data stored in the map data storage unit 416, 3D link formed by the 3D link formation unit 418, and the like. The output unit 413 can also include a voice guidance device.
The interface unit 414 connects the approximate altitude value specifying device 41 to a wireless network or the like.

The appropriate error width storage unit 415 associates the appropriate error width (i = k to n) of the altitude value (z _i ) specified by the appropriate error width specifying device 1 with the target point (x _i , y _i , z _i ). Saved.
Map information is stored in the map data storage unit 416. The map information includes information on road elements for defining map information such as links and nodes, information drawn on the map, and the like.
The mesh elevation data storage unit 417 stores mesh elevation data. For example, 10 m mesh elevation data can be stored as the mesh elevation data.

The target link selection unit 418 refers to the map data storage unit 416 and selects a link that is a target for specifying the approximate altitude value as the target link. The selection method is not particularly limited. For example, a link existing in an area arbitrarily extracted from the map data can be automatically selected. As another method, it may be designed to allow an operator to manually select a link. The number of target links to be selected is not limited to 1, and two or more adjacent links can be selected. The selected target link is stored in a target link storage unit (not shown).
The 3D link forming unit 419 refers to the mesh elevation data storage unit 417 and calculates the elevation value of each point coordinate on the target link to obtain a three-dimensional link (link L shown in FIG. 6A, hereinafter 3D). A link).

Based on the start point (M (x ₀ , y ₀ , z ₀ )) and the end point (N (x _z , y _z , z _z )) of the 3D link, the reference line forming unit 420 A reference line (same as I) connecting the end point is formed.
The first planned breakpoint coordinate determination unit 421 determines the first planned breakpoint coordinates (x _i1 , y _i1 ) at a point (O ₁ ) on the 3D link located farthest from the reference line. .
The first approximate broken line specifying unit 422 refers to the first broken point planned coordinate determination unit 421 and the appropriate error width storage unit 415, the 3D link L, the start point M (x ₀ , y ₀ , z ₀ ), end point _{N (x z, y z,} z z) and the first break point will coordinate _{(x i1, y} i1) a first break point will point error range is considered in _{(x i1, y i1, z} i1 _{= k~n)} by comparing the first fold line comprising, identifying a closest first fold line to the 3D link L first approximation polygonal line _{J 1} shown in (FIG. 6 (B)). That is, between each point (x _i , y _i , z _i ) on the 3D link and a point (x _i , y _i , z _j1 ) on the _first approximate broken line J ₁ corresponding to each point on the 3D link sum of squares of the difference between the vertical distance to identify the first approximation polygonal line J ₁ so as to minimize.

The second planned broken point coordinate determination unit 423 is configured to set the second planned broken point coordinates (x _i2 , y) at a point (O ₂ ) on the 3D link located farthest from the _first approximate broken line J _{1. i2} ) is determined.
The second approximate broken line specifying unit 424 refers to the second broken point planned coordinate determination unit 422 and the appropriate error width storage unit 415, the 3D link L, the start point M (x ₀ , y ₀ , z ₀ ), End point N (x _z , y _z , z _z ), the first planned break point (x _i1 , y _i1 , z _{i1 = k to n} ) and the second planned break point coordinates (x _i2 , y _i2 ) The second broken line closest to the 3D link L is compared with the second broken line including the second planned broken point (x _i2 , y _i2 , z _{i2 = k} to _n ) in which the error width is considered in FIG. Is identified as a _second approximate broken line (J ₂ shown in FIG. 6C). That is, between each point (x _i , y _i , z _i ) on the 3D link and a point (x _i , y _i , z _j2 ) on the _second approximate broken line J ₂ corresponding to each point on the 3D link sum of squares of the difference between the vertical distance to identify the second approximation broken line J ₂ so as to minimize. The mth folding point planned coordinates so that the elevation values at all the points on the approximate broken line fall within the appropriate error width (i = k to n) of the elevation values (z _i ) at the corresponding points on the 3D link. And the identification of the mth approximate broken line are repeated.

Approximate altitude value specifying unit 425, the elevation values of the break point will coordinates of the _{1~m (x i1~m, y i1~m)} O 1~m point on the approximate polygonal line _{J m} of the m corresponding to ' The first to _m approximate elevation values (z _{1m to} z _mm ) are specified. The identified approximate elevation value is stored in the approximate elevation value storage unit 426 in association with the coordinates of each point.

  As mentioned above, although embodiment of this invention has been described, you may implement combining 2 or more embodiment among these. Alternatively, one of these embodiments may be partially implemented. Furthermore, among these, two or more embodiments may be partially combined.

  The present invention is not limited to the description of the embodiments and examples of the invention described above. Various modifications may be included in the present invention as long as those skilled in the art can easily conceive without departing from the description of the scope of claims.

DESCRIPTION OF SYMBOLS 1 Appropriate error width identification apparatus 3 Map data storage part 4 Mesh elevation data storage part 5 Road gradient information storage part 6 Target point extraction part 8 Elevation value calculation part 10 1st error width calculation part 12 2nd error width calculation part 14 Proper error width identification part

Claims (13)

From the map data storage unit, a target point extraction unit that extracts a point on the road link that is the target of specifying the appropriate error range of the altitude value,
Based on mesh elevation data, an elevation value calculator that calculates the elevation value of the target point;
A first error width calculation unit that calculates a first error width based on the accuracy associated with the elevation value for the elevation value of the target point;
A second error width calculation unit that calculates a second error width of the target point based on road attribute information related to the gradient set in the road link and reference elevation data of other points on the road link When,
An appropriate error width specifying unit for specifying an overlapping portion of the first error width and the second error width as an appropriate error width at the target point;
An appropriate error width specifying device comprising: A 1-1 error width calculation unit that calculates a 1-1 error width resulting from the mesh elevation data source accuracy of the elevation value at the target point;
A 1-2 error width calculation unit for calculating a 1-2 error width due to the position accuracy of the target point,
The first error width calculator calculates the first error width by adding the 1-1 error width and the 1-2 error width;
The apparatus for specifying an appropriate error width according to claim 1.   3. The appropriate error width specifying device according to claim 1, wherein the reference elevation data includes a first error width calculated by the first error width calculation unit.   The appropriate error width specifying device according to claim 3, wherein the appropriate error width specifying unit specifies the appropriate error width of the target point in order based on the reference elevation data having a small first error width. A target point extraction step for extracting a point on a road link that is a target for specifying an appropriate error width of the altitude value from the map data storage unit;
An altitude value calculating step for calculating an altitude value of the target point based on mesh altitude data;
A first error width calculating step for calculating a first error width based on the accuracy associated with the elevation value for the elevation value of the target point;
A second error width calculating step of calculating a second error width of the target point based on road attribute information relating to the gradient set in the road link and reference elevation data of other points on the road link; When,
An appropriate error width specifying step for specifying an overlapping portion of the first error width and the second error width as an appropriate error width at the target point;
A method for specifying an appropriate error width. A 1-1 error width calculating step of calculating a 1-1 error width resulting from the accuracy of the mesh elevation data of the altitude value at the target point;
A 1-2 error width calculating step for calculating a 1-2 error width resulting from the position accuracy of the target point,
The first error width calculation step calculates the first error width by adding the 1-1 error width and the 1-2 error width;
The method for specifying an appropriate error width according to claim 5.   The method according to claim 5 or 6, wherein the reference elevation data includes the first error width calculated in the first error width calculation step.   8. The appropriate error width specifying method according to claim 7, wherein the appropriate error width specifying step specifies an appropriate error width at the target point in order based on the reference elevation data having a small first error width. A computer program for specifying an appropriate error width, wherein a computer is
From the map data storage unit, target point extraction means for extracting a point on the road link that is a target for specifying the appropriate error width of the altitude value,
An altitude value calculating means for calculating an altitude value of the target point based on mesh altitude data;
A first error width calculating means for calculating a first error width based on the accuracy associated with the elevation value for the elevation value of the target point;
Second error width calculation means for calculating a second error width of the target point based on road attribute information related to the gradient set in the road link and reference elevation data of other points on the road link When,
An appropriate error width specifying means for specifying an overlapping portion of the first error width and the second error width as an appropriate error width of the target point;
As a computer program. Said computer further
1-1 error width calculation means for calculating a 1-1 error width resulting from the mesh elevation data source accuracy of the elevation value at the target point;
Function as a 1-2 error width calculation means for calculating a 1-2 error width due to the position accuracy of the target point,
The first error width calculation means calculates the first error width by adding the 1-1 error width and the 1-2 error width.
The computer program according to claim 9.   The computer program according to claim 9 or 10, wherein the reference elevation data includes a first error width calculated by the first error width calculation means.   The computer program according to claim 11, wherein the appropriate error width specifying unit specifies an appropriate error width of the target point in order based on the reference elevation data having a small first error width.   The recording medium which records the computer program in any one of Claims 9-12.

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