JP2009129084A - Geography space data correction device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately correct geography space data even when there is any position deviation due to secular change in two maps. <P>SOLUTION: This geography space data collection device includes a difference absorbing part 7 for detecting a change region where any difference is generated due to the secular change of a first map and a second map, and for correcting the map data of the first map according to the detection result of the change region, and for absorbing a difference due to the secular change between two maps; a second position deviation detection part 9 for collating the first map and the second map whose map data have been corrected by the difference absorbing part 7, and for detecting the position deviation between the two maps, and configured to correct geography step data created by using the first map as a reference in response to the detection result of the position deviation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a geospatial data correction apparatus that corrects geospatial data relating to a facility of a geospatial created based on a first map so as to be adapted to a second map.

For example, in fields such as power, gas, and water and sewage, in order to manage facilities such as distribution lines, gas pipes and water pipes, map data of a reference map and geospatial data indicating the location and type of equipment Is used, and an equipment management system having a function of displaying the map data and geospatial data in an overlapping manner is used.
In some equipment management systems, it may be necessary to transfer geospatial data created based on a certain map to another equipment management system based on a different map.
In such a case, if the geospatial data is transferred as it is, the reference map is different, so that there may be a disadvantage that the geospatial data after the transfer does not match the map data.
Therefore, a geospatial data correction device for correcting geospatial data is required.

A conventional geospatial data correction device compares a first map with a second map, detects a positional shift between the two maps, and corrects the geospatial data according to the detection result of the positional shift. I am doing so.
For example, Patent Literature 1 below discloses a method of correcting geospatial data so that the distance from the facility to the road edge does not change.
Also, in Patent Document 2 below, a plurality of sets such as corner points of the block corresponding to the first map and the second map are created by the operator's operation, and the least square method is based on these corresponding points. Is a method for correcting geospatial data by obtaining affine transformation parameters and applying the affine transformation parameters to the geospatial data.

Here, there are two possible reasons for the difference between the two maps.
(1) Misalignment due to differences in surveying and mapping methods Due to errors that occur during the process of plotting surveying and surveying results on a map, misalignment occurs between the data measured and plotted separately. .
In addition, since some maps are simplified, there is a difference that a road that is bent and expressed in one map is expressed by a straight line.
The positional deviations belonging to this classification include (1-1) local positional deviation and (1-2) overall positional deviation.
(1-1) The overall displacement is a displacement that can be matched with the other map by performing operations such as translation, rotation, and enlargement / reduction on the entire map. (See FIG. 11 (a)).
(1-2) A local positional shift is a position where a part of a map, for example, a specific block cannot be adjusted to the other map unless operations such as translation, rotation, and enlargement / reduction are performed. This is a deviation (see FIG. 11B).

(2) Position shift due to secular change When the surveying time is different, road widening, new construction or relocation of the road may occur between the first survey and the second survey, and the road may change. obtain. For this reason, a difference arises between two maps (refer FIG.11 (c)).

Japanese Patent Publication No. 4-72268 (pages 4 to 6, Fig. 1) JP-A-8-190577 (paragraph number [0020], FIG. 1)

Since the conventional geospatial data correction apparatus is configured as described above, when the geospatial data is corrected so that the distance from the road edge to the facility does not change (Patent Document 1), the survey of (1) above, It is possible to absorb misalignment due to a difference in the drawing method. However, if there is a position shift due to secular change in (2) above, for example, the geospatial data will be corrected based on the road edge moved by the widening work. Since the equipment such as the manhole does not move even if is moved, there is a problem that an error may occur in correction of the geospatial data (see FIG. 11D).
In addition, when the geospatial data is corrected by applying the affine transformation parameters to the geospatial data (Patent Document 2), among the positional deviations due to the difference in the surveying and plotting methods of (1) above, (1-1) However, it is not possible to absorb the above-mentioned local positional deviation (1-2). In addition, since the intersection corners are set as corresponding points, if there is a position shift due to secular change in (2) above, if the intersection corners are shifted due to widening work, the corresponding point set is incorrect. Corresponding points will be included. If an affine transformation parameter is obtained with reference to an incorrect corresponding point, an incorrect affine transformation parameter is obtained. By applying the wrong affine transformation parameter to the geospatial data, the position of the equipment in the second map is shifted. There was a problem that sometimes occurred (see FIG. 11D).

  The present invention has been made to solve the above-described problems. A geospatial data correction apparatus capable of accurately correcting geospatial data even when there is a positional shift due to secular change between two maps. The purpose is to obtain.

  The geospatial data correction device according to the present invention corrects the map data of the first map and absorbs the overall positional deviation between the two maps, and the map data is corrected by the map data correction means. A change area in which a difference is caused due to a secular change between the corrected first map and the second map is detected, and the map data of the first map is corrected according to the detection result of the change area. The difference absorption means that absorbs the difference caused by the secular change between the two maps, the first map and the second map whose map data is corrected by the difference absorption means are collated, and the two maps A second position shift detection unit that detects the position shift, and the geospatial data correction unit generates a geography created on the basis of the first map in accordance with the detection result of the position shift by the second position shift detection unit. Geospatial data on spatial facilities It is obtained so as to correct the.

  According to this invention, the map data of the first map is corrected and the map data correction means for absorbing the overall positional deviation between the two maps, and the map data is corrected by the map data correction means. Two areas are detected by detecting a change area in which a difference occurs due to the secular change between the map and the second map, and correcting the map data of the first map according to the detection result of the change area. A difference absorbing means for absorbing a difference caused by a secular change between the first map and the second map whose map data has been corrected by the difference absorbing means is collated to detect a positional shift between the two maps. A geolocation related to the facility in the geospatial created based on the first map in accordance with the detection result of the misalignment by the second misalignment detection unit. Configured to correct spatial data Because, even if there is positional deviation due to aging between the two maps, there is an effect that it is possible to accurately correct the geospatial data.

Embodiment 1 FIG.
FIG. 1 is a block diagram showing a geospatial data correction apparatus according to Embodiment 1 of the present invention. In FIG. 1, a first map data storage unit 1 is a memory storing map data of a first map. .
The second map data storage unit 2 is a memory that stores map data of the second map.
The first misalignment detection unit 3 collates the first map with the second map and performs a process of detecting misalignment between the two maps. The first misregistration detection unit 3 constitutes first misregistration detection means.
The first misregistration information storage unit 4 is a memory that stores first misregistration information that is a detection result of misregistration by the first misregistration detection unit 3.

The map data correction unit 5 converts the map data of the first map stored in the first map data storage unit 1 according to the first position shift information stored in the first position shift information storage unit 4. Correction is performed to absorb the overall misalignment between the two maps. The map data correction unit 5 constitutes map data correction means.
The first corrected map data storage unit 6 is a memory for storing the map data of the first map corrected by the map data correction unit 5.

The difference absorption unit 7 detects a change region in which a difference is caused due to a secular change between the first map and the second map whose map data is corrected by the map data correction unit 5, and detects the change region The map data of the first map is corrected according to the result, and a process for absorbing the difference caused by the secular change between the two maps is performed. In addition, the difference absorption part 7 comprises the difference absorption means.
The second corrected map data storage unit 8 is a memory for storing the map data of the first map corrected by the difference absorption unit 7.

The second misalignment detection unit 9 collates the first map whose map data has been corrected by the difference absorption unit 7 with the second map, and performs a process of detecting misalignment between the two maps. The second misregistration detection unit 9 constitutes second misregistration detection means.
The second misregistration information storage unit 10 is a memory that stores second misregistration information that is a detection result of misregistration by the second misregistration detection unit 9.

The geospatial data storage unit 11 is a memory that stores geospatial data (for example, data indicating the position and type of equipment) related to the equipment of the geospatial created with reference to the first map.
The geospatial data correction unit 12 performs a process of correcting the geospatial data stored in the geospatial data storage unit 11 according to the second positional shift information stored in the second positional shift information storage unit 10. To do. The geospatial data correction unit 12 constitutes a geospatial data correction unit.
The corrected geospatial data storage unit 13 is a memory that stores the geospatial data corrected by the geospatial data correction unit 12.

  In the example of FIG. 1, the first misregistration detection unit 3, the map data correction unit 5, the difference absorption unit 7, the second misregistration detection unit 9, and the geospatial data, which are components of the geospatial data correction device. Although it is assumed that each of the correction units 12 is configured with dedicated hardware (for example, a semiconductor integrated circuit board on which an MPU is mounted), when the geospatial data correction apparatus is configured with a computer, , A program describing processing contents of the first misregistration detection unit 3, the map data correction unit 5, the difference absorption unit 7, the second misregistration detection unit 9, and the geospatial data correction unit 12 is stored in a computer memory. The program may be stored, and the CPU of the computer may execute the program stored in the memory.

FIG. 2 is an explanatory diagram showing an example of a map and geospatial data handled by the geospatial data correction apparatus of FIG.
In particular, FIG. 2A shows a first map and FIG. 2B shows a second map.
FIG. 2 (c) shows an example in which the geospatial data is overlaid on the first map, and FIG. 2 (d) shows the geospatial data overlaid on the second map without correction. An example is shown.
A black circle mark in FIG. 2C and a white circle mark in FIG. 2D indicate the positions of the equipment a and the equipment b such as manholes.

The map is expressed by a collection of line segments, and further, the line segments are expressed by start point coordinates and end point coordinates, and the first map data storage unit 1 and the first map data are displayed as tabular data as shown in FIG. 2 is stored in the map data storage unit 2.
In addition, the equipment is expressed by the type and position coordinates of the equipment, and is stored in the geospatial data storage 11 as tabular data as shown in FIG.
In the example of FIG. 2, there is an overall shift in the lower left direction with respect to the first map due to an error that has occurred in the process of plotting the second map.
Some of the lateral roads are widened due to widening work. Therefore, when the geospatial data of the facilities a and b is shifted without correction, as shown in FIG. 2 (d), the facility a enters the inside of a different block from the actual one, and the facility b is actually It will be mistakenly positioned at a position closer to the road edge than the position.
The geospatial data correction apparatus of FIG. 1 is configured for the purpose of correcting geospatial data so that such inconvenience does not occur.

Next, the operation will be described.
First, the first misalignment detection unit 3 includes the map data of the first map stored in the first map data storage unit 1 and the second map stored in the second map data storage unit 2. The positional deviation between the two maps is detected by collating with the map data of the map.
The process for detecting the positional deviation between the two maps is the same process as that of the conventional geospatial data correction apparatus. For example, the following processes (a), (b), and (c) are performed.

(A) Block association The block is detected from each of the map data of the first map and the map data of the second map, and the block is associated.
Here, the map data of the first map and the second map are stored in a table indicated by a set of start point coordinates and end point coordinates, as shown in FIG. 3A. Yes.
By finding a set of line segments constituting the closed area from this table, a table of area information as shown in FIG. 4A is created.
Since the line segment is a line segment indicating a road edge, the obtained area information corresponds to an area surrounded by the road, that is, a block.
The circumscribed rectangle is obtained for each of the obtained areas, and the center of the circumscribed rectangle and the sizes in the X direction and the Y direction are entered in the center coordinate and size column of the table of FIG.
The area information table of the first map and the area information table of the second map are compared, and the area where the center coordinates are close and the difference in size is small (the difference is equal to or less than the threshold value) Determine and associate.
FIG. 4B is an example of a table format expressing the association result between the first map and the second map.

(B) Creation of corresponding points A set of corresponding points is created based on the above-mentioned block association result.
That is, based on the area correspondence information (see FIG. 4B) obtained by the block association, a line segment correspondence table as shown in FIG. 4C is created.
Then, based on the information of the associated line segments, find the corresponding vertices between the first map and the second map (the corners of the intersection, the start point or the end point of the line segment constituting the city block), and these Is a set of corresponding points. The corresponding point information is described in a table as shown in FIG.

(C) Calculation of affine transformation parameters The coordinates on the first map are (X, Y), and the coordinates on the second map are (x, y).
Assuming that the result of applying any one of parallel movement, rotation, enlargement / reduction processing, or a combination thereof to the first map matches the second map, between the two maps Is represented by the 3 × 3 affine transformation matrix M as follows.

なお、アフィン変換パラメータａ，ｂ，ｃ，ｄ，ｔｘ，ｔｙは、第１の位置ずれ検出部３による位置ずれの検出結果（第１の位置ずれ情報）として、第１の位置ずれ情報記憶部４に格納される。 In equation (2), the six parameters a, b, c, d, tx, and ty are called affine transformation parameters, and the information on three or more sets of corresponding points obtained above (see FIG. 4D). ) Is substituted into the equation (1), and the equation (3) is solved by the least square method to obtain an affine transformation parameter.

The affine transformation parameters a, b, c, d, tx, and ty are the first misregistration information storage unit as the misregistration detection result (first misregistration information) by the first misregistration detection unit 3. 4 is stored.

  When the first misregistration detection unit 3 stores the first misregistration information in the first misregistration information storage unit 4, the map data correction unit 5 stores affine transformation parameters a and b as the first misregistration information. By correcting the map data of the first map stored in the first map data storage unit 1 according to, c, d, tx, and ty, the overall positional deviation between the two maps is absorbed. Implement the process.

なお、図５は地図補正の概念を示す説明図であり、地図データ補正部５により補正された第１の地図の地図データは第１の補正地図データ記憶部６に格納される。 That is, the map data correction unit 5 calculates the following coordinates (X, Y) on the first map by calculating the following equation (4) for the start point coordinates and end point coordinates of all line segments constituting the map. The first map is corrected by replacing it with (X ′, Y ′).

FIG. 5 is an explanatory diagram showing the concept of map correction. Map data of the first map corrected by the map data correction unit 5 is stored in the first corrected map data storage unit 6.

Here, if there is no secular change, surveying, or local misalignment in the process of mapping between the first map and the second map, the map data correction unit 5 performs correction to The first map and the second map almost coincide.
However, if there is a secular change or a local misalignment in the process of surveying or plotting between the first map and the second map, the correction process by the map data correction unit 5 alone is The first map and the second map do not match.

Since the difference absorption unit 7 absorbs the difference due to the secular change between the two maps, the difference is caused by the secular change between the first map and the second map after the correction by the map data correction unit 5. The generated change area is detected, and the map data of the first map is corrected according to the detection result of the change area.
Hereinafter, the processing content of the difference absorption part 7 is demonstrated concretely.
The difference absorption unit 7 detects the difference caused by the secular change in consideration of the property that “the relatively small difference is caused by the local shift and the relatively large difference is caused by the secular change”.

(A) Comparison of Areas The difference absorption unit 7 determines whether or not there is a change between the first map and the second map after correction by the map data correction unit 5.
As a determination method, there are several methods as shown below. Any one method may be used, and a plurality of methods may be combined.
(A1) Method of paying attention to the size of the difference area When the difference between the corrected first map and the second map is taken, only an area having a difference between them is extracted, and this area is set as the difference area.
The extracted difference area is a block area in the first map, but is a road area in the second map, or a road area in the first map, but is a block area in the second map. is there.
For each block area, the area of the difference area included in the corresponding area of the first map or the second map is evaluated. If the area is larger than a predetermined value, it is determined that the area has changed. .

(A2) Method of paying attention to the size of the block The area of the block region of the first map and the block region of the second map that are in a corresponding relationship is obtained, and the change occurs when the difference between the areas exceeds a predetermined value. Judge that there was.
(A3) Method of paying attention to the distance between adjacent town sections The area sandwiched between adjacent town areas is a road area.
For each of the corrected first map and second map, a table of area information as shown in FIG. 4A is created.
Based on the information on the center coordinates and the size, the circumscribed rectangles of the two areas overlap or are adjacent to each other and are detected as adjacent blocks.
A line segment constituting the adjacent block is examined, and a line segment having the same direction and having a distance between the two line segments equal to or smaller than a predetermined size is determined as a set of line segments facing each other (see FIG. 6C). .
The distance between the facing line segments indicates the road width. The road width is compared between the corresponding areas in the first map and the second map, and it is determined that there has been a change when the difference between the two exceeds a predetermined size.

(B) Reflection of change Next, the difference absorption unit 7 applies the detected change to the first map after correction by the map data correction unit 5.
Fig.7 (a) shows the block area in the 1st map after correction | amendment, FIG.7 (b) has shown the block area in the 2nd map corresponding to the block area.
It is assumed that the difference between the areas of the two regions exceeds a predetermined size and it is determined that there is a change.
When the two regions are overlapped as they are, the result is as shown in FIG. 7C, and there is no vertex that completely matches.
However, it is assumed that the actual change due to the widening work or the like is not all the vertices of the block, but one or two vertices.
Therefore, a vertex having no change is found, and the change is reflected to vertices other than the vertex with the vertex as a reference.

For the pair of corresponding vertices, the distance (shift amount) between the coordinate value (X ′, Y ′) and the coordinate value (x, y) is evaluated, and the vertex having the shortest distance is set as a reference vertex. Here, it is assumed that vertex 1 is selected as the reference vertex.
Next, the shift amount between the two vertices adjacent to vertex 1 (vertex 2 and vertex 4) is similarly evaluated, and the vertex with the smaller shift amount is selected (here, vertex 4 is selected). ).
The direction of the line segment toward the reference vertex 1 and the selected vertex 4 is set as the reference line segment direction.

Next, the region of the second map is translated so that the reference vertex 1 matches, and further rotated around the reference point so that the directions of the reference line segments match.
As a result, as shown in FIG. 7 (d), the line segments of the portions that have not changed substantially coincide with each other, and inconsistency occurs only in the changed portions. In this state, the area information of the second map is reflected in the area information of the corrected first map.
FIG. 8A shows an example of the change detection result, and FIG. 8B shows an example in which the change is reflected on the corrected first map based on the change detection result.
The map data of the first map in which the change is reflected by the difference absorption unit 7 is stored in the second corrected map data storage unit 8.
By the processing up to the difference absorption unit 7, the difference due to secular change is absorbed between the first map and the second map after the change is reflected.

When the difference absorbing unit 7 stores the map data of the first map after the change is reflected in the second corrected map data storage unit 8, the second positional deviation detection unit 9 stores the second corrected map data storage unit 8 in the second corrected map data storage unit 8. The map data of the first map stored and the map data of the second map stored in the second map data storage unit 2 are collated to detect a positional deviation between the two maps.
Since the misregistration detection process by the second misregistration detection unit 9 is the same as the misregistration detection process by the first misregistration detection unit 3, the description thereof is omitted.
The detection result of the positional deviation (second positional deviation information) by the second positional deviation detection unit 9 is stored in the second positional deviation information storage unit 10.

When the second misregistration detection unit 9 stores the second misregistration information in the second misregistration information storage unit 10, the geospatial data correction unit 12 stores the geospatial data according to the second misregistration information. The geospatial data stored in the unit 11 is corrected.
Hereinafter, the processing content of the geospatial data correction | amendment part 12 is demonstrated concretely.
FIG. 9 is an explanatory diagram showing correction processing by the geospatial data correction unit 12.

In particular, FIG. 9A shows facilities a and b included in geospatial data created based on the first map, and FIG. 9C shows the first map (after correction). The facilities a and b included in the geospatial data used as a reference are shown.
This geospatial data is determined by applying the affine transformation matrix M determined by the first misregistration detection unit 3 to the original geospatial facility data.
FIG. 9D shows the facilities a and b included in the geospatial data based on the first map after reflecting the change.
Since it is not necessary to change the position of the geospatial data before and after reflecting the change, the geospatial data is the same in (c) and (d).
FIG. 9B shows a state in which the equipment data obtained as a result of the data correction is displayed superimposed on the second map.
Although the difference due to secular change is absorbed between the first map and the second map after the change is reflected, it is caused by a local positional deviation and an error of corresponding point information in the first positional deviation detection. It is considered that the overall misalignment remains. Therefore, the geospatial data is corrected by reflecting the position shift detected by the second position shift detection unit 9.

Specifically, geospatial data is corrected in the following procedure. FIG. 10 is an explanatory diagram showing a correction procedure for geospatial data.
(1) First, the affine transformation matrix M determined by the first misregistration detection unit 3 is applied to the geospatial data created based on the first map, and the first map (after correction) is used as a reference. To obtain the geospatial data (see FIG. 10B).
(2) Next, the result obtained by applying the affine transformation matrix M ′ determined by the second misregistration detection unit 9 to the geospatial facility data is defined as geospatial data based on the second map. It outputs (refer FIG.10 (c)).
(3) At this stage, it should be possible to cope with the overall positional deviation, but it cannot cope with the local positional deviation only by the affine transformation.
Therefore, for each geospatial facility data, the second map from the facility position in (1) above to the closest road edge in the first map after reflecting the change and the facility position in (2) above. In FIG. 10, the distance to the nearest road edge is compared, and if the difference exceeds a predetermined amount, the position of the geospatial data is corrected so as to preserve the original distance (see FIG. 10D).
The geospatial data corrected by the geospatial data correction unit 12 is stored in the corrected geospatial data storage unit 13.

  As apparent from the above, according to the first embodiment, the map data correction unit 5 that corrects the map data of the first map and absorbs the overall positional deviation between the two maps, and the map data A change area in which a difference is caused due to a secular change between the first map and the second map whose map data is corrected by the correction unit 5 is detected, and the first area is detected according to the detection result of the change area. The difference absorption unit 7 that corrects the map data of the map and absorbs the difference caused by the secular change between the two maps, and the first map and the second map whose map data is corrected by the difference absorption unit 7 And a second misalignment detection unit 9 that detects a misregistration between the two maps, and the geospatial data correction unit 12 determines the misregistration detected by the second misregistration detection unit 9. , Land related to geospatial facilities created on the basis of the first map Since it is configured so as to correct the spatial data, even if there is positional deviation due to aging between the two maps, the effect that it is possible to accurately correct the geospatial data.

Embodiment 2. FIG.
In Embodiment 1 described above, an example of an equipment management system that manages equipment such as distribution lines, gas pipes, and water pipes laid on the road such as electric power, gas, and water and sewage systems has been described. The field is not limited to the facility management system as described above, and can be widely applied for the purpose of correcting geospatial data created on the basis of a certain map so as to match another different map.
For example, the present invention can be applied to the purpose of correcting the position data of a gas station created in accordance with a map of a certain car navigation system so as to automatically match the map of another car navigation system.
In addition, in the destination guidance service using the Internet, there is an example in which the name of the building is superimposed on the aerial photograph, but when the aerial photograph is updated, a misalignment between the two aerial photographs is detected. Thus, the present invention can be applied to the purpose of correcting the display position of the building name.

It is a block diagram which shows the geospatial data correction apparatus by Embodiment 1 of this invention. It is explanatory drawing which shows the example of the map and geospatial data which the geospatial data correction apparatus of FIG. 1 handles. It is explanatory drawing which shows map data and geospatial data. It is explanatory drawing which shows area | region information and correspondence information. It is explanatory drawing which shows the concept of map correction. It is explanatory drawing which shows the example of a detection of the line segment which faces. It is explanatory drawing which shows the block area from which the change was detected, the 1st map after a change reflection, etc. It is explanatory drawing which shows the 1st map after the example of a change detection and change reflection. It is explanatory drawing which shows the correction process by the geospatial data correction | amendment part 12. FIG. It is explanatory drawing which shows the correction | amendment procedure of geospatial data. It is explanatory drawing which shows an example of position shift etc.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 1st map data memory | storage part, 2nd 2nd map data memory | storage part, 3 1st position shift detection part (1st position shift detection means), 4 1st position shift information storage part, 5 Map data correction Part (map data correction means), 6 first correction map data storage part, 7 difference absorption part (difference absorption part), 8 second correction map data storage part, 9 second misalignment detection part (second Displacement detection means), 10 second displacement information storage unit, 11 geospatial data storage unit, 12 geospatial data correction unit (geospatial data correction unit), 13 corrected geospatial data storage unit.

Claims (3)

  The first map and the second map are collated to detect a positional deviation between the two maps, and according to the detection result of the positional deviation by the first positional deviation detection means. A map data correction unit that corrects the map data of the first map to absorb an overall positional shift between two maps, a first map in which the map data is corrected by the map data correction unit, and the map A change area where a difference is generated due to secular change between the second maps is detected, and the map data of the first map is corrected according to the detection result of the change area, and the two maps are corrected. A difference absorbing unit that absorbs a difference due to secular change, a first map whose map data is corrected by the difference absorbing unit, and the second map are collated to detect a displacement between two maps. Second misalignment detection means and the second position In accordance with the detection result of the positional deviation by the detectors are, geospatial data correction apparatus that includes a geospatial data correcting means for correcting the geospatial data concerning facilities of the geospatial created first reference map.   The difference absorbing means is present in the block area surrounded by the road existing in the first map whose map data is corrected by the map data correcting means, and in the second map corresponding to the block area. If the difference in size is equal to or greater than a predetermined threshold, the above block area is detected as a change area where a difference has occurred due to secular change between the two maps. The geospatial data correction apparatus according to claim 1, wherein:   The difference absorption means compares the width of the road existing in the first map whose map data is corrected by the map data correction means and the road existing in the second map corresponding to the road. If the difference in width is equal to or greater than a predetermined threshold, the area where the road exists is detected as a change area in which a difference occurs due to secular change between two maps. The geospatial data correction apparatus according to claim 1.

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